Description:
TECHNICAL FIELD
The present invention relates to checking the health condition of a battery in a power station and, more particularly, to checking the health condition of an Extra High Voltage/Ultra High Voltage/High Voltage station battery banks (both Ni Cad and lead acid type batteries) by carrying out a discharge process for them and utilizing the wasted discharge energy for station auxiliary purposes.
BACKGROUND OF THE INVENTION
A common way of specifying battery capacity is to provide the battery capacity as a function of the time in which it takes to fully discharge the battery (note that in practice the battery often cannot be fully discharged). The notation to specify battery capacity in this way is written as Cx, where x is the time in hours that it takes to discharge the battery. C10 = Z (also written as C10 = xxx) means that the battery capacity is Z when the battery is discharged in 10 hours. When the discharging rate is halved (and the time it takes to discharge the battery is doubled to 20 hours), the battery capacity rises to Y. The discharge rate when discharging the battery in 10 hours is found by dividing the capacity by the time. Therefore, C/10 is the charge rate. This may also be written as 0.1C. Consequently, a specification of C20/10 (also written as 0.1C20) is the charge rate obtained when the battery capacity (measured when the battery is discharged in 20 hours) is discharged in 10 hours. The nominal voltage of a galvanic cell is fixed by the electrochemical characteristics of the active chemicals used in the cell, the so called cell chemistry. The actual voltage appearing at the terminals at any particular time, as with any cell, depends on the load current and the internal impedance of the cell and this varies with, temperature, the state of charge and with the age of the cell.
In present scenario lead acid and Nickel cadmium batteries of various capacities such as 100 Ah, 120 Ah, 150 Ah, 250 Ah, 400 Ah had been installed across various power stations, depending upon the load of the control system and protection system. Generally, battery banks and battery chargers are connected in parallel to feed up the load of the station such as various measuring meters, all protection relays, full operation of the switchgear, fire protection systems, remote indication and alarm purposes. So, the role of battery bank in power stations is vast as any other power utility.
Right now, system routine tests like measurement of terminal cell voltage for all the battery cells, specific gravity of every battery cell and measurement of strap resistance for the whole battery bank are carried out once in a month. Apart from that capacity discharge test in terms of C-10 is carried out on all the battery banks, once in two years in order to ascertain the health of the battery banks. The energy discharged while carrying out the discharge process is completely wasted.
In view of the aforementioned problem, discharge sets of various models are available. Some discharge sets are available with regenerative property but the discharged energy in that equipment is used for recharging the discharged battery bank. Moreover, the available regenerative sets are heavy and bulky and so cannot be easily transported from one site to another.
Contrary to the existing discharge sets, embodiments of the present invention convert the discharged energy into 230 V AC for auxiliary station supply and purposes. The developed discharge sets are made compartment wise with each compartment being light in weight and can be easily decoupled. These compartments can again be easily assembled in site and so over all the set is very much user friendly.
Therefore, in view of the exiting prior art, there is a dire need for a capacity discharge test for a battery in a power station using a portable discharge test set to convert the huge amount of wasted energy during discharge of battery bank into useful energy and for carrying out the discharge tests for the battery banks at all stations safely and properly.
SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
An object of the present disclosure is to provide a capacity discharge test for a battery in a power station using discharge test set to convert the huge amount of wasted energy during discharge of battery bank into useful energy and for carrying out the discharge tests for the battery banks at all stations safely and properly.
An object of the present disclosure is to provide checking the health condition of the EHV/UHV/HV station battery banks (both Ni Cad and lead acid type batteries) by carrying out discharge process for them and utilizing the wasted discharge energy for station auxiliary purposes.
According to an aspect, an arrangement for capacity discharge test for a battery in a power station by using a discharge test set, having regenerative property, the arrangement comprising: a battery bank operably coupled to a battery charger and a hybrid regenerative capacity discharge test set, said discharge test set comprising a specially designed inverter operably coupled to a voltage stabilizer, and the voltage stabilizer is operably coupled to a transformer; and a AC grid or a solar grid, operably coupled to the transformer of the discharge test set, to utilize AC power converted by the transformer, for auxiliary power station supply and purposes is disclosed.
According to an embodiment, the inverter of the discharge test set is configured to convert a 110V DC output of a battery bank into raw 110V AC.
According to an embodiment, the voltage stabilizer of the discharge test set is configured to provide a fixed output of 110V AC output with variable input DC voltages of the discharging battery bank, varying from 121V DC to 99V DC.
According to an embodiment, the raw converted AC is fed to the transformer having a rated voltage ratio of 110/230 V and KVA capacity of 3 KVA, wherein the transformer is configured to convert the 110V AC to 230V AC.
According to an embodiment, the 230V AC output of the transformer of the discharge test set is configured to be fed to an AC grid or a solar grid of that station.
According to another aspect, a method for performing capacity discharge test for a battery in a power station, performed by an arrangement comprising a discharge test set, having regenerative property is disclosed.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:
Figures 1 illustrates a schematic diagram of a system for checking the health condition of the EHV/UHV/HV station battery banks by carrying out discharge process for them, according to prior art.
Figure 2 illustrates a schematic diagram of a system for checking the health condition of the EHV/UHV/HV station battery banks by carrying out discharge process for them, according to an embodiment of the present invention.
Figure 3 illustrates a schematic diagram of a hybrid regenerative capacity discharge test set, according to an embodiment of the present invention.
Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary implementations of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.
Features that are described and/or illustrated with respect to one implementation may be used in the same way or in a similar way in one or more other implementations and/or in combination with or instead of the features of the other implementations.
According to an embodiment, an arrangement for capacity discharge test for a battery in a power station by using a discharge test set, having regenerative property, the arrangement comprising: a battery bank operably coupled to a battery charger and a hybrid regenerative capacity discharge test set, said discharge test set comprising a specially designed inverter operably coupled to a voltage stabilizer, and the voltage stabilizer is operably coupled to a transformer; and a AC grid or a solar grid, operably coupled to the transformer of the discharge test set, to utilize AC power converted by the transformer, for auxiliary power station supply and purposes. The inverter of the discharge test set is configured to convert a 110V DC output of a battery bank into raw 110V AC. The voltage stabilizer of the discharge test set is configured to provide a fixed output of 110V AC output with variable input DC voltages of the discharging battery bank, varying from 121V DC to 99V DC. The raw converted AC is fed to the transformer having a rated voltage ratio of 110/230 V and KVA capacity of 3 KVA, wherein the transformer is configured to convert the 110V AC to 230V AC. The 230V AC output of the transformer of the discharge test set is configured to be fed to an AC grid or a solar grid of that station.
In the prior art, according to an arrangement as illustrated in Fig. 1, almost 150 nos. of battery banks had been installed in various stations with control voltage of banks varying from 110 V DC to 220 V DC mainly. In order to ascertain or assess the health of these battery banks C-10 discharge is being carried out on these battery banks every two years. In the past, the capacity discharge was carried out via a specially designed discharge set having few resistances, connected in parallel with each other and segregated from each other by DC MCBs. Depending upon load currents, required to be discharged by battery banks those MCBs were switched on one after another. During this C-10 discharge, considering average capacity of 150 Ah and 110 V battery bank, 15 Amps were discharged every hour for 6 hours. Average energy dissipated through the resistors for each battery bank= 15 * 110 * 6=9900 Watt hour =9.9 kilowatt hour. Total energy dissipated for all 150 battery banks= 9.9*150= 1485 kilowatt hour. So, every two years, 1485 units of energy are being wasted for carrying out this test, which is not at all accepted in today’s scenario as per as conservation of energy is concerned.
According to an embodiment, the schematic diagram of Fig. 2 illustrates a discharge set for carrying out discharge tests for battery banks in different stations. The discharge set comprises an inverter, which will at first convert the 110 V DC output of the battery bank into 110 V raw AC. Then this raw AC will be fed into a transformer of rated voltage ratio: - 110/230 V and KVA capacity: - 3 KVA, which will convert the 110 V AC to 230 V AC. And in between the inverter and the transformer, a voltage stabilizer is connected to provide a fixed output of 110 V AC output with variable input DC voltages of discharging battery bank, varying from 121 V DC to 99 V DC. Now the 230 V AC output of the transformer will be connected to a AC grid or a solar grid of that station, after proper synchronism checking over there. With the help of the discharge set, discharge for the battery bank can be carried out safely without wasting any energy, and by utilizing the discharged energy into useful energy for the grid.
According to an embodiment, Fig. 3 illustrates a hybrid regenerative capacity discharge test set comprises of three components – an inverter, a voltage stabilizer and a transformer. The inverter, at first converts the 110V DC output of the battery bank into 110V raw AC. This inverter is unique and not readily available in market due to its unique voltage specification. So, it is specially designed, in consultation with OEM, and as per voltage requirement. The voltage stabilizer is configured to provide a fixed output of 110 V AC output with variable input DC voltages of discharging battery bank, varying from 121 V DC to 99 V DC. Then this raw AC will be fed into a transformer of rated voltage ratio: -110/230 V and KVA capacity: - 3 KVA, which will convert the 110 V AC to 230 V AC. Overall the whole hybrid regenerative capacity discharge set is a unique innovation due to non-availability of such types of regenerative set in market.
Some of the non-limiting advantages of the system and method for checking the health condition of the EHV/UHV/HV station battery banks by carrying out discharge process for them are:
1. Very low cost solution for converting the unused discharge energy, generated during the test into useful energy.
2. Capacity discharge test for a battery in a power station by using discharge test set, having regenerative property.
3. Easily portable function and such a low cost implementation.
Although checking the health condition of the EHV/UHV/HV station battery banks (both Ni Cad and lead acid type batteries) by carrying out discharge process for them and utilizing the wasted discharge energy for station auxiliary purposes has been described in language specific to structural features and/or methods, it is to be understood that the implementations disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of the system and method checking the health condition of the EHV/UHV/HV station battery banks (both Ni Cad and lead acid type batteries) by carrying out discharge process for them and utilizing the wasted discharge energy for station auxiliary purposes.
LIST OF SYNONYMS
Some of the abbreviations used in this disclosure form have been described as follows :-
Ah: Capacity of battery in ampere hour
DC: Direct current
MCB: Miniature circuit breaker
AC: Alternating current
I/P: Input
V: Volts (Unit of voltage)
A: Amperes (Unit of current)
O/P: Output
B+: Battery positive
B-: Battery negative
TC+: Tapped cell positive
L+: Load positive
L-: Load negative
, Claims:
1. An arrangement for capacity discharge test for a battery in a power station by using a discharge test set, having regenerative property, the arrangement comprising:
a battery bank operably coupled to a battery charger and a hybrid regenerative capacity discharge test set, said discharge test set comprising a specially designed inverter operably coupled to a voltage stabilizer, and the voltage stabilizer is operably coupled to a transformer; and
a AC grid or a solar grid, operably coupled to the transformer of the discharge test set, to utilize AC power converted by the transformer, for auxiliary power station supply and purposes.

2. The arrangement as claimed in claim 1, wherein the inverter of the discharge test set is configured to convert a 110V DC output of a battery bank into raw 110V AC.

3. The arrangement as claimed in claim 1, wherein the voltage stabilizer of the discharge test set is configured to provide a fixed output of 110V AC output with variable input DC voltages of the discharging battery bank, varying from 121V DC to 99V DC.

4. The arrangement as claimed in claim 1, wherein the raw converted AC is fed to the transformer having a rated voltage ratio of 110/230 V and KVA capacity of 3 KVA, wherein the transformer is configured to convert the 110V AC to 230V AC.

5. The arrangement as claimed in claim 1, wherein the 230V AC output of the transformer of the discharge test set is configured to be fed to an AC grid or a solar grid of that station.

6. The arrangement as claimed in claim 1, wherein the arrangement is configured for HV stations with DC control voltage of 110V DC.

7. A method for performing capacity discharge test for a battery in a power station, performed by an arrangement comprising a discharge test set, having regenerative property, as claimed in any one of claims 1-6.