TECHNICAL FIELD [0001] 10 The present invention relates to an electric power control system. In particular, the present invention relates to an electric power control system which regulates the balance between supply and demand of electric power in a system. BACKGROUND ART [0002] A popularly employed method for controlling an electric power system is centralized control of an electric power system (for example, see Patent Document 1 ). Centralized control of 15 an electric power system requires building of a mechanism for concentrating information and a large-scale control system for grasping and analyzing the whole system configuration condition and also optimizing the whole system. Such a system is easily applied in countries and regions where electric power supply infrastructure has developed to some extent, because it can be built additionally. However, in regions including emerging countries where electric power 20 infrastructure has not developed, new building of the above system requires a large investment in development of the infrastructure. [0003] 2 On the other hand, in terms of optimization of the whole system, there is a proposed approach of distributed control, which is less efficient but enables electric power control without a large investment by regulating voltages between neighboring power plants or comparatively near power plants (for example, see Patent Document 2). In control of an electric power system, 5 generally, matrix calculation is carried out on the basis of information of each generator, and a solution is found. In the case of concentrated control mentioned above, large-scale matrix calculation should be done because all the information is included. On the other hand, in the case of distributed control, sparse matrix calculation is done because control between neighboring or near power plants is executed, and therefore, the amount of calculation is considerably less. 10 IS [0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. JP-A 2002-165367 Patent Document 2: Japanese Unexamined Patent Application Publication No. JP-A 20 I 0-057311 [0005] In recent years, in consideration of the protection of global environment and energy security, natural energy such as solar light, biomass and wind power has been introduced worldwide. However, such natural energy has a problem with the stability of supply and, as such power sources become more popular in the future, it will become a critical issue how to keep the 20 stability of the whole electric power network. In other words, when it comes to electric power generation by natural energy, new entrants to electric power supply increase because the introduction cost is low though the power generation capacity of each generator is small, and 3 moreover, it is worried about that enough reserves cannot be secured in a small-scale electric power system configured mostly by such generators. SUMMARY 5 [0006] 10 15 Accordingly, an object of the present invention is to solve the abovementioned problem that enough reserves cannot be secured in a small-scale electric power system and it is difficult to keep stability. [0007] An electric power control system as an aspect of the present invention is connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming the electric power, and includes: a supplied energy acquiring means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load means; and an electric power supply and demand controlling means for changing a status of supply of electric power to a distribution line with the load means connected depending on a total supplied energy and a total consumed energy, the total supplied energy being a total of the 20 acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. [0008] 5 4 Further, a computer program as another aspect of the present invention is a computer program including instructions for causing an information processing device, which is connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming the electric power, to realize: a supplied energy acquiring means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load means; and an electric power supply and demand controlling means for changing a status of supply t~ ~ eiectr'.c power to a distribution line with the load means connected depending on a total supplied energy and a total consumed energy, the total supplied energy being a total of the acquired supp~ed energy, and the total consumed energy being a total of the acquired consumed energy. 15 [0009] Further, an electric power control method as another aspect of the present invention includes: acquiring a supplied energy which is an amount of electric power supplied from an electric power supplying means for supplying electric power, and also acquiring a consumed energy which is an amount of electric power consumed by a load means for accepting supply of 20 electric power and consuming the electric power; and changing a status of supply of electric power to a distribution line with. the load means connected depending on a total supplied energy and a total consumed energy, the total supplied 5 energy being a total of the acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. [0010] Further, an electric power control system as another aspect of the present invention is 5 connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming the electric power, and includes: a supplied energy acquiring means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a ~sumed energy acquiring means for acquiring a consumed energy, the consumed 10 energy being an.c A first exemplary embodiment of the present invention will be described referring to Figs. 1A to 5. Figs. 1A, 1B and 2 are diagrams for describing the configuration of an electric 5 power control system, and Figs. 3 to 5 are diagrams for describing the operation thereof. [0016] As shown in Figs. 1A and 1B, an electric power control system according to the present invention is a system which controls electric power in an electric power system 5, and is built in a distribution substation 1 connected with the electric power system 5. One Next, a second exemplary embodiment of the present invention will be described referring to Figs. 6 to 9. Figs. 6 and 7 are diagrams for describing the configuration of an electric j l 20 power control system, and Figs. 8 and 9 are diagrams for describing the operation thereof. [0040] In this exemplary embodiment, as described later, the electric power control part 13 changes a total supplied energy by transmitting or receiving electric power to or from another 5 device depending on a total supplied energy which is the total of acquired electric power supplies and a total consumed energy which is the total of acquired consumed energy. In particular, in a case where an electric power supply and demand difference (IG-LJ) which is the difference between a total supplied energy G and a total consumed energy L calculated as described above does not fall within a predetermined electric power variation allowance C, the electric pewer I 0 control part 13 transmits or receives electric power to or from another device and carries out necessary electric power regulation. For example, as described in the following specific example, the electric power control part 13 may carry out regulation of energy between set groups, or may carry out regulation of energy in cooperation with an extemal electric power system. I5 [0041] To be specific, as shown in Fig. 6, the electric power control system in this exemplary embodiment is a system which controls electric power in an electric power system I5, and is built in the distribution substation I connected with the electric power system I5. To the distribution substation 1, the electric power system I5, one or a plurality of generators 2 which generate and supply electric power, and one or a plurality of loads 4 which consume electric 20 power are connected. [0042] The distribution substation I includes a control device I 0' configuring an electric power 21 control system controlling electric power, and the control device 1 0' in this exemplary embodiment includes a plurality of control parts 21, 22 and 23 corresponding to the control device 10 in the first exemplary embodiment described above. In the example shown in Fig. 6, the control device 10' includes three control parts 21, 22 and 23, but may include more control 5 parts 21, 22, 23. [0043] The control parts 21, 22 and 23 each have a similar configuration to the configuration that the control part 1 0 in the first exemplary embodiment has. In other words, as shown in Fig. 7, the control part 21 includes the supplied energy acquisition part 11, the consumed energy 10 acquisition part 12, the electric power control part 13, and the storage part 14. As the components of the other control parts 22 and 23, only electric control parts 22a and 23a are shown in Fig. 7, respectively, but the control parts 22 and 23 also include other components in the same manner as the control part 21. [0044] 15 Further, as shown in Fig. 6, the control parts 21, 22 and 23 belong to preset groups G 1, G2 and G3, respectively. With this, the generator 2 and the distribution line 3 to which the load 4 is connected belong to each of the groups G1, G2 and G3. Consequently, each of the control parts 21, 22 and 23 is configured to manage, as a controlled object, the generator 2 and the distribution line 3 (the load 4) which belong to the same group as the control part itself. In other 20 words, the electric control part 13 in each of the control parts 21, 22 and 23 controls the condition of supply and demand between electric power generated by the generator 2 belonging to the same group and also supplied from the electric power system 15 and electric power 22 consumed by the load 4, on the basis of the total supplied energy G and the total consumed energy L as described above. [0045] Further, each of the control parts 21, 22 and 23 in this exemplary embodiment is 5 connected to the other control part (the other device) belonging to the different group as shown in Figs. 6 and 7. Then, each of the electric power control parts 13, 22a and 23a of the control parts 21, 22 and 23 also has a function of controlling an electric power supply and demand condition in cooperation with each other. An example will be described referring to a flowchart ofFig. 8. 10 [0046] First, in the same manner as described above, the electric power control part 13 sets a predetermined electric power variation allowance C in consideration of a given electric power variation which can be managed by a distribution substation (step S21). Then, the electric power control part 13 reads out from the storage part 44 the amount of electric power generated by the 15 generators 2 and the amount of electric power supplied by the electric power system 15, which are acquired by the supplied energy acquisition part 11, and calculates a total supplied energy G which is the total of these amounts (step S22). Further, the electric power control part 13 acquires consumed energy of the loads 4 measured by the electric power measuring instruments 6 and stored into the storage part 14, and obtains a total consumed energy L which is the total of 20 these consumed energy (step S23). [0047] Next, the electric power control part 13 compares the total supplied energy G and the 23 total consumed energy L, which are calculated in the abovementioned marmer. To be specific, the electric power control part 13 calculates an electric power supply and demand difference (IG-Li) which represents the difference between the total supplied energy G and the total consumed energy L, and determines whether the electric power supply and demand difference (IG-Li) is 5 equal to or less than the electric power variation allowance C or the electric power supply and demand difference (IG-Li) is more than the electric power variation allowance C (step 824). In a case where the electric power supply and demand difference (IG-Li) is equal to or less than the electric power variation allowance C (step 824: Yes), the electric power control part 13 does not change the current condition of electric power supply and demand. 10 [0048] On the other hand, in a case where the electric power supply and demand difference (IG-Li) is more than the electric power variation allowance C (step 824: No), the electric power control part 13 executes control to regulate the balance between electric power supply and demand among the groups (step 825). For example, in a case where the total supplied energy G 15 in its group is more than the total consumed energy L, the group has excess electric power. Therefore, the electric power control patt 13 executes control to act as a generator which supplies electric power to the other group. Moreover, in a case where the total consumed energy L in its group is more than the total supplied energy G, the group has insufficient electric power. Therefore, the electric power control part 13 executes control to act as a load supplied with 20 electric power from the other group. [0049] The electric power control part 13 thus controls so that the difference between a total rj/" 24 supplied energy and a total consumed energy in each group falls within a predetermined electric power variation allowance C as in the frrst exemplary embodiment. Consequently, it becomes possible to regulate the balance between electric power supply and demand among groups without placing a heavy burden on a generator of a specific group. 5 [0050] Further, in a case where the total consumed energy L in its group is more than the total supplied energy G, the group has insufficient electric power. Therefore, the electric power control part 13 may execute control to stop supply of electric power to the distribution lines 3 with the hads 4 belonging to its group connected and make these distribution lines 3 belong to the other 10 'WffiiP having excess electric power. In other words, in a case where the total supplied energy G in its group is more than the total consumed energy L, the electric power control part 13 may execut~ control to additionally connect the distribution lines 3 with the loads 4 belonging to the other group connected, to the group of the electric power control part 13. The electric power control pmt 13 may thus control so that the difference between a total supplied energy and a total 15 consumed energy in each group falls within a predetermined electric power variation allowance C as in the first exemplary embodiment. [0051] The system shown in Fig. 6 may have a function of, when electric power supply from the electric power system 15 to the distribution substation I stops, causing the generators 2 to 20 independently supply electric power to the distribution lines 3 or causing controlled objects such as the generators 2 and the loads 4 managed in the separate groups to supply electric power to the distribution lines 3 in cooperation with each other. Consequently, even if the electric power 25 system 15 stops supply of electric power for a reason such as overload, the electric power control part 13 can keep supplying constant electric power to the loads 4 in the distribution substation I. [0052] The distribution substation 1 described above and the system which controls the balance 5 between electric power supply and demand have self-similarity. Therefore, by applying controlled objects such as the generators 2 and the loads 4 stated above or controlled objects managed in separate groups g to an electric power system 25 including a plurality of distribution substations 1A and 1 B as shown in Fig. 9, it is possible to build a system which executes electric pewer eGntr~ so that the sum of electric power supplies in the respective distribution substations 10 1AarnUB~theminimum. [0053] In Fig. 9, the di~tribution substations 1A and 1B are connected to the large-scale electric power system 25. In this configuration, when one of the distribution substations 1A and 1B falls into a power shortage situation, it can be supplied with electric power via the large-scale electric 15 power system 25. Moreover, when requested, any of the distribution substation IA and IB having surplus electric power can supply electric power to the large-scale electric power system. Consequently, electric power supplies in the respective distribution substations 1A and IB can be minimized, and then, control to make the sum of the electric power supplies minimum can be executed. 20 [0054] Thus, according to the present invention, a small-scale electric power system including a plurality of generators and loads is configured, the total of electric power generated by all the 26 generators included in the system and electric power supplied from an electric power system and the total of consumptions by all the loads are measured, and the energy generated by each of the generators and the loads are regulated depending on the degree of excess and deficiency. Therefore, firstly, fme regulation of each of the generators is not necessary, and therefore, 5 regulation of the balance between electric power supply and demand in the system is enabled at low cost and by a simple control method. Secondly, the balance between supply and demand is regulated by using the electric power system of the present invention and the controllable groups in the electric power system as control units, and the regulation method basically has self-similarity and does not ~~ the number of the generators or the total amount of the 10 loads. Accordingly, it is easy :tn hiemmhically build an electric power system, and its high scalability enables flexible configuration of an electric power system. 15 [0055] A third exemplary embodiment of the present invention will be described referring to Figs. 10 to 21. Figs. 1 0 and 11 are diagrams showing the state of energy in an electric power control system. Fig. 12 is a diagram showing the configuration of a control device configuring the electric power control system. Figs. 13 to 21 are diagrams showing an example of the configuration of the electric power control system and the operation thereof. 20 [0056] First, referring to Figs. 10 and 11, the state of control of electric power supply and demand will be described. The electric power control system in this exemplary embodiment is a 27 system which controls electric power in the electric power system 5 as described in the fust exemplary embodiment. To the distribution substation 1, the electric power system 5 and the generators 2 each serving as an electric power supplying means and the loads 4 each serving as a load means are connected as shown in Fig. lB. Consequently, to the distribution substation 1, the 5 sum of a given energy G main of electric power from the electric power system 5 and generated energy G 1 to G m of electric power generated by the generators 2 is supplied as shown in Fig. 1 O(B). Moreover, from the distribution substation 1, the sum of energy L 1 to L m of electric power to be consumed by the respective loads 4 is supplied to the respective loads 4 as shown in Fig. lO(B). In Fig. lO(B), a total suppliedenergyGwhich is the total of electric power supplies 10 is identical to a total consumed energy L whicl! isiire rota! of c~nsumed \)nergy, which shows a state in which electric power supply and demand are balanced. [0057] I In the configuration described above, for example, assuming supply of electric power G_main from the electric power system 5 stops as shown in Fig. lO(C) and supply of electric 15 power to the load 4 with consumed energy L 4 is stopped so that an electric power supply and demand difference which is the difference between the total supplied energy G and the total consumed energy L falls within a given range as mentioned above, the balance between supply and demand of the total supplied energy G and the total consumed energy L is not achieved and generated electric power is wasted by an amount denoted by symbol F as shown in Fig. 1 O(C). 20 Such a problem may occur, for example, when the loads 4 are uncoupled in unit of the distribution line 3 and the total of consumed energy by the loads 4 connected to this distribution line 3 is large. 28 [0058] Thus, it is desirable to execute control to stop supply of electric power to only the loads with consumed energy L 4b and L 4c and supply electric power to only the load with consumed energy L_ 4a corresponding to the generated energy denoted by symbol F as shown in Fig. ll(C). 5 Therefore, in this exemplary embodiment, in order to realize a state as shown in Fig. 11 (C), the system is configured to be capable of setting in detail the unit of the loads to which supply of electric power is stopped. Below, the electric power control system in this exemplary embodiment will be described in detail. 10 [0059] First, the distribution substation I in this exemplary ~OOdiment includes a bus coupler 17 which can connect a plurality of distribution lines 3 as shown in Fig. 12. Then, the electric power system 5, the generator 2 and the load 4 are connected to the distributio~ line 3 connected to the bus coupler 17. Consequently, as in the other exemplary embodiments described above, the distribution substation I accepts supply of electric power from the electric power system 5 15 and the generator 2, and supplies electric power to the load 4. [0060] In a first example in this exemplary embodiment, as shown in Fig. 13, a plurality of loads 4 are connected to each of the distribution lines 3 to which the loads 4 are connected. Among the loads 4 connected on the same distribution line 3, a switch 50, 51, 52, 53 which 20 switches the distribution line 3 between connected and disconnected is placed. In other words, when the switch 50, 51, 52, 53 is in the connected state is when electric power can be transmitted to the whole distribution line 3. On the other hand, when the switch 50, 51, 52, 53 is in the 29 disconnected state is when electric power can be transmitted up to the switch on the distribution line but electric power cannot be transmitted downstream from the switch. [0061] Further, each of the switches 50, 51, 52 and 53 includes a wireless communication 5 device 50a and operates so as to switch the distribution line 3 between connected and disconnected in response to a command via wireless communication from the control device 10. Meanwhile, each of the switches 50, 51, 52 and 53 need not include the wireless communication device 50a and may receive a command from the control device 10 via wired communication. As shown in Fig. 13, the generator 2 also includes a wireless communication device a!ld regulates 10 the generated energy in response to a command from the control device 10. [0062] Further, the control device 10 in this exemplary embodiment includes the supplied: energy acquisition part 11, the consumed energy acquisition pmi 12, the electric power control part 13 and a communication part 16 as shown in Fig. 12. Moreover, the communication part 16 15 transmits control commands to the switch 50 m1d the generator 2 via an antenna 16a. [0063] To be specific, the electric power control part 13 first calculates an electric power supply and demand difference which is the difference between the total of electric power supplies from the electric power system 5 and the generator 2 and the total of consumed energy 20 by the loads 4 as described above. Then, the electric power control part 13 controls the state of supply and demand of electric power so that the electric power supply and demand difference falls within the range of the electric power vm·iation allowance C. When executing control to 30 stop supply of electric power to the loads 4, the electric power control part 13 outputs a command to disconnect the switch 50, 51, 52, 53 to the communication part 16. The communication part 16 transmits the disconnection command to the switch 50, 51, 52, 53 via wireless communication and, upon receiving the command, the switch 50, 51, 52, 53 disconnects 5 the distribution line 3 on which it is placed. Moreover, the electric power control part 13 may transmit a command to connect the switch 50, 51, 52, 53 depending on the electric power supply and demand difference. [0064] Furthermore, for stopping supply of electric power to all the loads 4 connected te 2 10 single distribution line 3, the electric power control part 13 outputs a command to stop supp!J of electric power to the specific distribution line 3 to the bus coupler 17. [0065] Now referring to Figs. 13 and 14, an example of the operation of stopping electric power supply to the load 4 will be described. First, in the state shown in Fig. 13, all the switches 15 50, 51, 52 and 53 are in the connected state, and therefore, all the loads 4 are supplied with electric power. After that, as stated above, due to decrease of supply supplied energy, stop of electric power supply to part of the loads 4 is determined depending on an electric power supply and demand difference, and a disconnection command is outputted to the switches denoted by reference numerals 50 and 52. Then, as shown with dotted lines in Fig. 14, electric power supply 20 to the loads 4 located downstream from the respective switches 50 and 52 is stopped. To be specific, as shown in Fig. 14, electric power is supplied to loads denoted by symbol Llllocated upstream from the switch 50 among the loads 4 connected on the same distribution line 3, 31 whereas electric power supply to loads denoted by symbol L12 located downstream from the switch 50 is stopped. [0066] Thus, according to this exemplary embodiment, by controlling the status of connection 5 of the switch 50 or the like placed on the distribution line 3, the status of electric power supply to the distribution line 3 to which the loads 4 are connected can be changed, and electric power supply to part of the loads on the distribution line 3 can be stopped. Therefore, a consumed energy can be regulated in detail by connecting/disconnecting the loads 4. As a result, it is possible to execute proper control to make an electric power supply and demand difference fall 10 within a given range, and it is possible to reduce the waste of supply of electric power. [0067] Next, a second example in this exemplary embodiment will be described referring to Figs. 15 to 17. In this example, as shown in Fig. 15, a single distribution line 30 to which a plurality of loads 4 are connected is formed like a loop. On this loop-shape distribution line 30, 15 three switches 51, 52 and 53 are placed. Meanwhile, the number of the switches 51, 52, 53 is not limited to three. [0068] In the state shown in Fig. 15, the three switches 51, 52 and 53 are in the connected state on the loop-shape distribution line 30, and therefore, all the loads 4 on the distribution line 30 are 20 supplied with electric power. Assuming a consumed energy then decreases and it is determined to stop electric power supply to part of the loads 4 depending on an electric power supply and demand difference as stated above, when a disconnection command is outputted to the switches 32 denoted by reference numerals 51 and 53, electric power supply to the loads 4 located between the switches 51 and 53 is stopped as shown with a dotted line in Fig. 16. On the other hand, when a disconnection command is outputted to the switches denoted by reference numerals 51 and 52, electric power supply to the loads 4 located between the switches 51 and 52 is stopped as 5 shown with a dotted line in Fig. 17. [0069] Thus, according to the second example in this exemplary embodiment, it is possible with a simple configuration to set the status of supply of electric power to the loads to various statuses. In other words, it is possible to regulate a consumed energy in detail by 10 connecting/disconnecting the loads 4. As a result, it is possible to properly control so that an electric power supply and demand difference falls within a given range, and it is possible to reduce the waste of supply of electric power. [0070] Next, a third example in this exemplary embodiment will be described refening to Figs. 15 18 and 19. In this example, as shown in Fig. 18, double distribution lines 31 and 32 are connected to the bus coupler 17. The loads 4 are configured to be able to be connected to either or both of the double distribution lines 31 and 32. For example, consumers corresponding to the loads 4 are connected to either or both of the distribution lines 31 and 32 depending on the conditions of supply of electric power (electricity rate, stability, and so on). 20 [0071] The electric power control part 13 in this exemplary embodiment outputs a command to stop electric power supply to either of the double distribution lines 31 and 32 to the bus coupler 5 33 17 so that an electric power supply and demand difference falls within the range of the electric power variation allowance C. Upon accepting such a command, the bus coupler 17 operates to stop electric power supply to the designated distribution line. [0072] To be specific, firstly, in the state shown in Fig. 18, electric power is supplied to both the double distribution lines 31 and 32, and all the loads (for examples, reference numerals 41 to 45) are supplied with the electric power. Assuming a supplied energy then decreases and it is determined to stop electric power supply to part of the loads 4 depending on an electric power supply and demand difference as stated above, by stopping electric power supply to the 10 distribution line denoted by reference numeral 32, electric power supply to the loads denoted by 15 reference numerals 43, 44 and 45 is stopped as shown with a dotted line in Fig. 19. Because electric power supply to the distribution line denoted by reference numeral 31 is continued, electric power supply to the loads denoted by reference numerals 41 and 42 is continued. [0073] Thus, according to the third example in this exemplary embodiment, it is possible with a simple configuration to set the status of electric power supply to the loads to various statuses. In other words, it is possible to regulate a consumed energy in detail by connecting/disconnecting the loads 4. As a result, it is possible to execute proper control to make an electric power supply and demand difference fall within a given range, and it is possible to reduce the waste of supply 20 of electric power. [0074] Next, a fomth example in this exemplary embodiment will be described referring to 34 Figs. 20 and 21. In this example, as shown in Fig. 20, a plurality of loads 4 are connected to a single distribution line 3, and a switch 60 as described above is placed between the distribution line 3 and each of the loads 4. For example, this switch 60 is equipped with a wireless communication device as described above, and can receive a connection/disconnection command 5 from the control device 10. [0075] Assuming a supplied energy decreases and it is determined to stop electric power supply to part of the loads 4 depending on an electric power supply and demand difference as stated above, by outputting a disconnection command to a given switch, electric power supply to the li} loads shown with a dotted line in Fig. 21 is stopped, for example. [0076] Thus, according to the fourth example in this exemplary embodiment, it is possible with a simple configuration to set the status of electric power supply to the loads to various statuses. In other words, it IS possible to regulate a consumed energy in detail by 15 connecting/disconnecting the loads 4. As a result, it is possible to execute proper control to make an electric power supply and demand difference fall within a given range, and it is possible to reduce the waste of electric power supply. [0077] Further, in the exemplary embodiment described above, the order of priority of loads 20 may be decided in advance, and a load to which electric power supply is continued or stopped may be decided on the basis of the order of priority. To be specific, the order of priority of loads may be decided in accordance with the conditions of contracts with users, or may be decided in 35 accordance with the importance of the loads. For example, the electric power control part 13 executes control to stop supply of electric power to a load of low importance so that an electric power supply and demand difference falls within the range of the electric power variation allowance C. 5 [0078] 10 Furthermore, an example of a favorable method for controlling to supply electric power to a load and stop electric power supply is as follows. An operator with responsibility for supply has a control policy and, on the basis of the control policy, it is possible to execute control to supply ®ctrie power to a load and stop electric power supply. [0079] j The whole or part of the exemplary embodiments disclosed above can be described as the following supplementary notes. The overview of the configurations of an electric power 15 control system, a computer program and an electric power control method according to the present invention will be described below. However, the present invention is not limited to the following configurations. [0080] (Supplementary Note 1-1) 20 An electric power control system connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming the electric power, the electric power control system comprising: 5 36 a supplied energy acqmrmg means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a consmned energy acquiring means for acquiring a consumed energy, the consmned energy being an amount of electric power consmned by the load means; and an electric power supply and demand controlling means for changing a status of supply of electric power to a distribution line with the load means connected depending on a total supplied energy and a total consmned energy, the total supplied energy being a total of the acquired supplied energy, and the total consumed energy being a total of the acquired consmned energy. 10 [0081] (Supplementary Note 1-2) The electric power control sf;;tem according to Supplementary Note 1-1, wherein the electric power supply and demand controlling means calculates an electric power supply and demand difference representing a difference between the total supplied energy and the total 15 consumed energy, changes a status of supply of electric power to the distribution line with the load means connected, and executes control so that the electric power supply and demand difference falls within a predetermined range set in advance. 20 [0082] (Supplementary Note 1-3) The electric power control system according to Supplementary Note 1-2, wherein when a value as a result of subtracting the total supplied energy from the total consumed energy is larger than a preset value, the electric power supply and demand controlling means changes a 37 status of supply of electric power to the distribution line so as to stop supply of electric power to some of load means supplied with electric power, and makes the electric power supply and demand difference fall within a predetermined range set in advance. [0083] 5 (Supplementary Note 1-4) The electric power control system according to Supplementary Note 1-3, wherein the electric power supply and demand controlling means executes control to stop supply of electric power to at least part of the distribution line with the load means connected, and makes the electric power supply and dernand-~fference faiT within a predetermined range set in advance. 10 [0084] (Supplementary Note 1-5) The electric power control system according 4 Supplementary Note 1-4, wherein the electric power supply and demand controlling means controls a switch, and makes the electric power supply and demand difference fall within a predetermined range set in advance, the switch 15 being placed in middle of the distribution line with the load means connected, and the switch switching the distribution line between connected and disconnected. [0085] (Supplementary Note 1-6) The electric power control system according to Supplementary Note 1-5, wherein the 20 electric power supply and demand controlling means controls a plurality of switches placed on a same distribution line formed into a loop shape, and makes the electric power supply and demand difference fall within a predetermined range set in advance. 38 [0086] (Supplementary Note 1-7) The electric power control system according to any one of Supplementary Notes 1-4 to 1-6, wherein the electric power supply and demand controlling means executes control to stop 5 supply of electric power to one of double distribution lines, and makes the electric power supply and demand difference fall within a predetermined range set in advance, the double distribution lines being distribution lines to which a same load means can be connected. 10 [0087] (Supplementary Note 1-8) The electric power control system according ta ·a!lo/ ,one of Supplementary Notes 1-2 to 1-7, wherein when a value as a result of subtracting the total consumed energy from the total supplied energy is larger than a preset value, the electric power supply ~d demand controlling means executes control to supply electric power to a new distribution line with a new load means connected, and makes the electric power supply and demand difference fall within a 15 predetermined range set in advance. [0088] (Supplementary Note 1-9) The electric power control system according to any one of Supplementary Notes 1-2 to 1-8, comprising a plurality of electric power supply and demand controlling means, the electric 20 power supply and demand controlling means each belonging to any of groups determined in advance, and the electric power supply and demand controlling means each targeting the electric power supplying means and/or the load means set to belong to its group for control of electric 39 power supply and demand, wherein the electric power supply and demand controlling means each supply electric power to a distribution line to which the load means belonging to another of the groups is connected, and/or stops supply of electric power to a distribution line to which the load means 5 belonging to its group is connected, and makes the electric power supply and demand difference in its group fall within a predetermined range set in advance. [0089] (Supplementary Note 1-10) A computer program comprising instructions for causing an- informatioR processing 1 0 device, which is connected to an electric power supplying means for suppl.~>:ing electric power 15 and a load means for accepting supply of electric power and consuming the electric power, to realize: j a supplied energy acquiring means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load means; and an electric power supply and demand controlling means for changing a status of supply of electric power to a distribution line with the load means connected depending on a total supplied energy and a total consumed energy, the total supplied energy being a total of the 20 acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. [0090] 40 (Supplementary Note 1-11) The computer program according to Supplementary Note 1-10, wherein the electric power supply and demand controlling means calculates an electric power supply and demand difference representing a difference between the total supplied energy and the total consumed 5 energy, changes a status of supply of electric power to the distribution line with the load means connected, and executes control so that the electric power supply and demand difference falls within a predetermined range set in advance. 10 [0091] (Supplementary Note 1-12) The computer program according to Supplementary Note 1-11, wherein when a value as a result of subtracting the total supplied energy from the total consumed energy is larger than a preset value, the electric power supply and demand controlling means changes a status of supply of electric power to the distribution line so as to stop supply of electric power to some of load means supplied with electric power, and makes the electric power supply and demand difference 15 fall within a predetermined range set in advance. [0092] (Supplementary Note 1-13) An electric power control method comprising: acquiring a supplied energy which is an amount of electric power supplied from an 20 electric power supplying means for supplying electric power, and also acquiring a consumed energy which is an amount of electric power consumed by a load means for accepting supply of electric power and consuming the electric power; and 41 changing a status of supply of electric power to a distribution line with the load means connected depending on a total supplied energy and a total consumed energy, the total supplied energy being a total of the acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. 5 [0093] (Supplementary Note 1-14) The electric power control method according to Supplementary Note 1-13, comprising: calculating an electric power supply and demand difference representing a difference between the total supplied energy and the total consumed energy, changing a status of supply of 10 electric power to the distribution line with the load means connected, and executing control so that the electric power supply and demand difference falls within a predetermined range set in 15 advance. [0094] (Supplementary Note 1-15) The electric power control method according to Supplementary Note 1-14, comprising: when a value as a result of subtracting the total supplied energy from the total consumed energy is larger than a preset value, changing a status of supply of electric power to the distribution line so as to stop supply of electric power to some of load means supplied with electric power, and making the electric power supply and demand difference fall within a 20 predetermined range set in advance. [0095] (Supplementary Note 2-1) 42 An electric power control system connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming the electric power, the electric power control system comprising: a supplied energy acquiring means for acquiring a supplied energy, the supplied energy 5 being an amount of electric power supplied from the electric power supplying means; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load means; and an electric power supply and demand controlling means for, depending on a total supplied energy and a total consumed energy, transmitting and/or receiving electric power to 10 and/or from another device to change the total supplied energy, the total supplied energy being a total of the acquired supplied energy, and the total consumed energy being a total of the acquired 15 consumed energy. [0096] (Supplementary Note 2-2) The electric power control system according to Supplementary Note 2-1, wherein the electric power supply and demand controlling means calculates an electric power supply and demand difference representing a difference between the total supplied energy and the total consumed energy, and transmits and/or receives electric power to and/or from another device to change the total supplied energy, thereby executing control so that the electric power supply and 20 demand difference falls within a predetermined range set in advance. [0097] (Supplementary Note 2-3) 43 The electric power control system according to Supplementary Note 2-2, comprising a plurality of electric power supply and demand controlling means, the electric power supply and demand controlling means each belonging to any of groups determined in advance, and the electric power supply and demand controlling means each targeting the electric power supplying 5 means and/or the load means set to belong to its group for control of electric power supply and demand, wherein the electric power supply and demand controlling means each transmits and/or receives electric power to and/or from another device placed outside its group to change the total supplied energy in its group, thereby making the electric power supply and demand difference in 10 its group fall within a predetermined range set in advance. [0098] (Supplementary Note 2-4) The electric power control system according to Supplementary Note 2-3, wherein the electric power supply and demand controlling means each transmit and/or receive electric power 15 to and/or from another of the electric power supply and demand controlling means belonging to another of the groups, thereby making the electric power supply and demand difference in its group fall within a predetermined range set in advance. 20 [0099] (Supplementary Note 2-5) The electric power control system according to Supplementary Note 2-4, wherein: the electric power supplying means includes an electric power system which supplies a predetermined energy and a generator which generates and supplies electric power; and 44 the electric power supply and demand controlling means belonging to each of a plurality of distribution substations to which different electric power supplying means and/or different load means belong, respectively, transmits and/or receives electric power to and/or from another of the electric power supply and demand controlling means belonging to another of the 5 distribution substations, thereby executing control so that a sum of electric power supplies in the plurality of distribution substations becomes minimum. [0100] (Supplementary Note 2-6) The electric power control system according to any one of Supplementary Notes 2-1 to lO 2-5, wherein: the electric power supplying means includes an electric power system which supplies a j predetermined electric power amount of electric power and a generator which generates and supplies electric power; and the electric power supply and demand controlling means has a function of, when electric 15 power supplied from the electric power system to the distribution substation to which the electric power supplying means and/or the load means belongs stops, causing the generator to supply electric power to the load means. [0101] (Supplementary Note 2-7) 20 The electric power control system according to any one of Supplementary Notes 2-2 to 2-5, wherein: the electric power supplying means includes a generator which generates and supplies 45 electric power; and when a value as a result of subtracting the total consumed energy from the total supplied energy is larger than a preset value, the electric power supply and demand controlling means controls a status of electric power generation so that energy generated by the generator decreases, 5 thereby making the electric power supply and demand difference fall within a predetermined range set in advance. [0102] (Supplementary Note 2-8) A computer program comprising instructions for causing an information processing 1\l 4e¥ice, wlllch is connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming the electric power, to 15 realize: a supplied energy acquiring means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load means; and an electric power supply and demand controlling means for, depending on a total supplied energy and a total consumed energy, transmitting and/or receiving electric power to and/or from another device to change the total supplied energy, the total supplied energy being a 20 total of the acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. [0103] 46 (Supplementary Note 2-9) The computer program according to Supplementary Note 2-8, wherein the electric power supply and demand controlling means calculates an electric power supply and demand difference representing a difference between the total supplied energy and the total consumed 5 energy, and transmits and/or receives electric power to and/or from another device to change the total supplied energy, thereby executing control so that the electric power supply and demand difference falls within a predetermined range set in advance. 10 [0104] (Supplementary Note 2-10) Tile compW.er pr~ according to Supplementary Note 2-9, wherein: a plurality of electric power supply and demand controlling means are included, the electric power supply and dem~d controlling means each belongs to any of groups determined in advance, and the electric power supply and demand controlling means each targets the electric power supplying means and/or the load means set to belong to its group for control of electric 15 power supply and demand; and the electric power supply and demand controlling means each transmits and/or receives electric power to and/or from another device placed outside its group to change the total supplied energy in its group, thereby making the electric power supply and demand difference in its group fall within a predetermined range set in advance. 20 [0105] (Supplementary Note 2-11) An electric power control method comprising: 47 acquiring a supplied energy which is an amount of electric power supplied from an electric power supplying means for supplying electric power, and also acquiring a consumed energy which is an amount of electric power consumed by a load means for accepting supply of electric power and consuming the electric power; and 5 depending on a total supplied energy and a total consumed energy, transmitting and/or receiving electric power to and/or from another device to change the total supplied energy, the total supplied energy being a total of the acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. [0106] 10 (Supplementary Note 2-12) The electric power control method according to Supplementary Note 2-11, comprising: calculating an electric power supply and :demand difference representing a difference between the total supplied energy and the total consumed energy, and transmitting and/or receiving electric power to and/or from another device to change the total supplied energy, 15 thereby executing control so that the electric power supply and demand difference falls within a predetermined range set in advance. [0107] (Supplementary Note 2-13) The electric power control method according to Supplementary Note 2-12, wherein: 20 a plurality of electric power supply and demand controlling means are included, the electric power supply and demand controlling means each belongs to any of groups determined in advance, and the electric power supply and demand controlling means each targets the electric 48 power supplying means and/or the load means set to belong to its group for control of electric power supply and demand, the electric power supply and demand controlling means being a means for transmitting and/or receiving electric power to and/or from an external device and changing the total supplied energy to execute control so that the electric power supply and 5 demand difference falls within a predetermined range set in advance; and the electric power supply and demand controlling means each transmits and/or receives electric power to and/or from another device placed outside its group to change the total supplied energy in its group, thereby making the electric power supply and demand difference in its group fall within a predetermined range set in advance. 10 [0108] (Supplementary Note 3-1) An electric power control system connected to at least on~ generator and at least one load supplied with electric power via a distribution line, the electric power control system comprising: 15 a generated energy acquiring means for acquiring a generated energy, the generated energy being an amount of electric power generated by the generator; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load; and an electric power supply and demand controlling means for calculating an electric 20 power supply and demand difference and controlling a supply and demand status of electric power generated by the generator and electric power consumed by the load so that the electric power supply and demand difference falls within a predetermined range set in advance, the 5 49 electric power supply and demand difference representing a difference between a total generated energy and a total consumed energy, the total generated energy being a total of the acquired generated energy, and the total consumed energy being a total of the acquired consumed energy. [0109] According to the present invention, the system controls so that the difference between a total generated energy and a total consumed energy falls within an electric power variation allowance. The total electric power generation amount is the amount of electric power generated by all the generators directly connected to a distribution substation, and the total consumption is the sum of the loads placed on all the distribution lines direetly oconnected t6-the distribution I 0 substation Therefore, stable electric power supply in a distribution:substatimu:an be achieved. [0110] (Supplementary Note 3-2) The electric power control system according to Supplementary Note 3-1, wherein when a value as a result of subtracting the total consumed energy from the total generated energy is 15 larger than a preset value, the electric power supply and demand controlling means controls a status of electric power generation so that energy generated by the generator decreases, and makes the electric power supply and demand difference fall within a predetermined range set in 20 advance. [0111] According to the present invention, when a total consumed energy of a plurality of distribution lines is less than a total generated energy of the generator by a predetermined amount, the system controls to decrease energy generated by the generator. Consequently, the 50 difference between the total consumed energy of the plurality of distribution lines and the total generated energy of the generator falls within a predetermined range, so that stable electric power supply in a distribution substation can be achieved. [0112] · 5 (Supplementary Note 3-3) The electric power control system according to Supplementary Note 3-1, wherein when a value as a result of subtracting the total consumed energy from the total generated energy is larger than a preset value, the electric power supply and demand controlling means controls a status of electric power supply so as to supply electric power to a new distribut«m rrne with .a 10 new load connected, and makes the electric power supply and demand difference 1l:Ht witr.in a predetermined range set in advance. [0113] According to the present invention, when a total consumed energy of the distribution line is less than a total generated energy of the generator, another distribution line outputted from 15 a distribution substation is added as a controlled object. Consequently, the difference between the total consumed energy of a plurality of distribution lines and the total generated energy of the generator can be made to fall within a predetermined range, and electric power can be supplied to more loads in a stable manner. [0114] 20 (Supplementary Note 3-4) The electric power control system according to Supplementary Note 3-1, wherein when a value as a result of subtracting the total generated energy from the total consumed energy is 51 larger than a preset value, the electric power supply and demand controlling means controls a status of electric power supply so as to stop supply electric power to some of distribution lines to which the load supplied with electric power is connected, and makes the electric power supply and demand difference fall within a predetermined range set in advance. 5 [0115] According to the present invention, when a total consumed energy of distribution lines is more than a total generated energy of the generator by a predetermined amount, supply of electric power to the distribution line which is a controlled object is stopped. Consequently, the difference between the total consumed energy of the plurality of distribution lines and the total 10 generated energy of the generator can be made to fall within a predetermined range, and stable electric power supply can be achieved. [0116] (Supplementary Note 3-5) The electric power control system according to any one of Supplementary Notes 3-1 to 15 3-4, wherein when the electric power supply and demand difference cannot be made to fall within a predetermined range set in advance by control of an electric power supply and demand status on the generator and/or the load which are controlled objects, the electric power supply and demand controlling· means transmits and/or receives electric power to and/or from a predetermined external device which is different from the generator and/or the load as the 20 controlled objects, and makes the electric power supply and demand difference fall within a predetermined range set in advance. [0117] 52 According to the present invention, even when the difference between a total consumed energy of a plurality of distribution lines and a total generated energy of the generator cannot be made to fall within a predetermined range only by control of a controlled object, the system can perform necessary regulation of an electric power amount in cooperation with the outside. 5 [0118] (Supplementary Note 3-6) The electric power control system according to any one of Supplementary Notes 3-1 to 3-5, comprising a plurality of electric power supply and demand controlling means, the electric power supply and demand controlling means each belonging to any of groups determined in 10 advance, and the electric power supply and demand controlling means each targeting the generator and/or the load set to belong to its group for control. [0119] According to the present invention, it is possible to manage controlled objects including a plurality of distribution lines outputted from a distribution substation and the generator by 15 separating into a plurality of groups. Therefore, it is possible to easily manage small-scale electric power systems structured by the respective groups, and it is also possible to connect these systems to build a large-scale network. 20 [0120] (Supplementary Note 3-7) The electric power control system according to Supplementary Note 3-6, wherein the electric power supply and demand controlling means transmits and/or receives electric power to and/or from another of the electric power supply and demand controlling mean~ belonging to 53 another of the groups, and makes the electric power supply and demand difference in its group fall within a predetermined range set in advance. [0121] According to the present invention, it is possible to exchange electric power between the 5 groups so that the difference between a total consumed energy of a plurality of distribution lines and a total generated energy of the generator falls within a predetermined range in the respective controlled objects managed in the separate groups. [0122] (Supplementary Note 3-8) 10 The electric power control system according to Supplementary Note 3-6 or 3-7, wherein the electric power supply and demand controlling means supplies electric power to the distribution line with the load connected belonging to another of the groups, and/or stops supply of electric power to the distribution line with the load connected belonging to its group, thereby making the electric power supply and demand difference in its group fall within a predetermined 15 range set in advance. [0123] According to the present invention, it is possible to shift a distribution line to be managed between the groups so that the difference between a total consumed energy of a plurality of distribution lines and a total generated energy of the generator falls within a 20 predetermined range in the respective controlled objects managed in the separate groups. [0124] (Supplementary Note 3-9) 54 The electric power control system according to any of Supplementary Notes 3-1 to 3-8, wherein the generator has a function of supplying electric power to the load when electric power supplied to a distribution substation to which the generator and/or the load belongs stops. [0125] 5 According to the present invention, when electric power supplied to a distribution substation stops, supply of electric power to a distribution line included in a controlled object can be performed by the single controlled object or by the respective controlled objects managed in the separate groups in cooperation with each other. [0126] 10 (Supplementary Note 3-10) The electric power control system according to any one of Supplementary Notes 3-1 to 3-9, wherein each of the electric power supply and demand controlling means respectively belonging to a plurality of distribution substations to which different generators and/or different loads belong, respectively, transmits and/or receives electric power to and/or from another of the 15 electric power supply and demand controlling means belonging to another of the distribution substations, and controls so that a sum of supplied energy in the respective distribution substations becomes minimum. [0127] According to the present invention, a controlled object or controlled objects managed in 20 the separate groups cooperate with a plurality of distribution stations, whereby it is possible to control so that the sum of the supplied energy to the distribution substations becomes the minimum. 55 [0128] (Supplementary Note 3-11) A computer program comprising instructions for causing an information processing device, which is connected to at least one generator and at least one load supplied with electric 5 power via a distribution line, to realize: a generated energy acquiring means for acquiring a generated energy, the generated energy being an amount of electric power generated by the generator; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amonnt of electric power consumed by the load; and an electric power supply and demand controlling means for calculating an electric power supply and demand difference and controlling a supply and demand status of electric power ge~erated by the generator and electric power consumed by the load so that the electric power supply and demand difference falls within a predetermined range set in advance, the electric power supply and demand difference representing a difference between a total generated 15 energy and a total consumed energy, the total generated energy being a total of the acquired 20 electric power generation amount, and the total consumed energy being a total of the acquired consumed energy. [0129] (Supplementary Note 3-12) The computer program according to Supplementary Note 3-11, wherein when a value as a result of subtracting the total consumed energy from the total generated energy is larger than a preset value, the electric power supply and demand controlling means controls a status of electric 56 power generation so that energy generated by the generator decreases, and makes the electric power supply and demand difference fall within a predetermined range set in advance. [0130] (Supplementary Note 3-13) 5 An electric power system control method comprising: acquiring a generated energy which is an amount of electric power generated by at least one generator, and also acquiring a consumed energy which is an amount of electric power consumedby at least one load supplied with electric power via a distribution line; and calmilating-an electric power supply and demand difference and controlling a supply and I 0 demand status -of electric power generated by the generator and electric power consumed by the load so that the electric power supply and demand difference falls within a predetermined range set in advance, the electri4 power supply and demand difference representing a difference between a total generated energy and a total consumed energy, the total generated energy being a total of the acquired generated energy, and the total consumed energy being a total of the 15 acquired consumed energy. [0131] (Supplementary Note 3-14) The electric power system control method according to Supplementary Note 3-13, compnsmg: 20 controlling a status of electric power generation so that energy generated by the generator decreases and making the electric power supply and demand difference fall within a predetermined range set in advance, when a value as a result of subtracting the total consumed 57 energy from the total generated energy is larger than a preset value. [0132] The computer program described above is recorded in a storage device or recorded on a computer-readable recording medium. For example, the recording medium is a portable medium 5 such as a flexible disk, an optical disk, a magneto-optical disk and a semiconductor memory . ., [0133] Although the present invention is described above referring to the exemplary embodiments, the present invention is not limited to the exemplary embodiments. The configurations and detaits 'Of the present invention may be changed and modified in various 1 0 manners that can be understood by one skilled in the art within the scope of the present invention. INDUSTRIAL APPLICABILITY [0134] 15 Because the present invention enables configuration of a decentralized autonomous electric power supply system, introduction of a small-scale and unstable generator such as renewable energy is facilitated. Moreover, for example, in developing countries where a power supply capability is considerably lower than a demand due to delay of building of electric power infrastructure, applying the technique of the present invention makes it possible to connect 20 small-scale electric power systems to build a large-scale network and makes it possible to increase return on investment of building of an electric power supply network. [0135] 58 The present invention is based upon and claims the benefit of priority from Japanese patent applications No. 2013-022001, filed on February 7, 2013, and No. 2013-081130, filed on April 9, 2013, the disclosures of which are incorporated herein in their entireties by reference. 5 DESCRIPTION OF REFERENCE NUMERALS [0136] 1, 1A, 1B distribution substation 2 generator 3, 30, 31,32 distribution line 10 4 load 5, 15, 25 electric power system 6 electric power measuring instrument 10 control device 11 supplied energy acquisition prut 15 12 consumed energy acquisition prut 13, 22a, 23a electric power control part 14 storage prut 16 communication prut 17 bus coupler 20 21, 22, 23 50 to 53,60 control prut switch CLAIMS 1. An electric power control system connected to an electric power supplying means for supplying electric power and a load means for accepting supply of electric power and consuming 5 the electric power, the electric power control system comprising: a supplied energy acquiring means for acquiring a supplied energy, the supplied energy being an amount of electric power supplied from the electric power supplying means; a consumed energy acquiring means for acquiring a consumed energy, the consumed energy being an amount of electric power consumed by the load means; and an electric power supply and demand controlling means fur changing a status of supply of electric power to a distribution line with the load means connected depending on a total supplied energy and a total consumed energy, the total supplied energy being: a total of the acquired supplied energy, and the total consumed energy being a total of the acquired consumed energy. 2. The electric power control system according to Claim 1, wherein the electric power supply and demand controlling means calculates an electric power supply and demand difference representing a difference between the total supplied energy and the total consumed energy, changes a status of supply of electric power to the distribution line with the load means 20 connected, and executes control so that the electric power supply and demand difference falls within a predetermined range set in advance. 3. The electric power control system according to Claim 2, wherein when a value as a result of subtracting the total supplied energy from the total consumed energy is larger than a preset value, the electric power supply and demand controlling means changes a status of supply of electric power to the distribution line so as to stop supply of electric power to some of load 5 means supplied with electric power, and makes the electric power supply and demand difference fall within a predetermined range set in advance. 4. The electric power control system according to Claim 3, wherein the electric power supply and demand controlling means executes control to stop supply of electric power w at least I 0 part of the distribution line with the load means connected, and makes the electric pov.