DESC:FIELD
The present disclosure generally relates to racking systems for electrical switchgear equipment. More particularly, the present disclosure relates to an automated racking system for a circuit breaker.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Rack circuit breaker into a switchgear – The phrase ‘rack … into … switchgear’ or ‘racked … into … switchgear’ used hereinafter in the disclosure refers to an operation which involves movement of a circuit breaker from a test position to a service position in a switchgear panel.
Rack circuit breaker out of a switchgear – The phrase ‘rack … out of … switchgear’ or ‘racked … out of … switchgear’ used hereinafter in the disclosure refers to an operation which involves movement of a circuit breaker in a switchgear panel from a service position to a test position.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Electrical switchgear equipment typically houses large and heavy circuit breakers for protecting electrical circuits from the damage that may be caused due to overloads or short circuits.
The process of making or breaking the electrical connection between the circuit breakers and the bus in the switchgear by moving the breaker from test to service position and vice versa is called racking. Currently, the circuit breakers are racked into or racked out of the switchgear manually as per a standard operating procedure (SOP). Typically, the procedure to rack a circuit breaker into or out of the switchgear requires an operator to insert a racking handle (i.e., a crank) into a slot provided on a panel or an enclosure housing the circuit breaker and rotate it in clockwise or anti-clockwise direction. This puts the operator directly in front of the breaker enclosure. Therefore, the process of racking circuit breakers, particularly, the high-capacity circuit breakers (for e.g., 22kV to 33kV breakers) is wrought with danger to operating personnel’s safety as it may lead to undesirable/faulty electrical conditions such as arc flash. Any fault while racking the circuit breakers can cause a significant injury to the operating personnel. Therefore, this task is generally carried out by wearing an arc suit.
In addition to this, the conventional racking mechanisms require the operating personnel to apply a large amount force to rack the circuit breaker. The number of breaker racking operations to be carried out may increase during, for e.g., major maintenance activities and may thereby cause fatigue to the operating person. Further, the force required for carrying out racking operations may cross ergonomic limitations. Equipment failure during racking of breaker or a wrong operation can lead to severe injury and even fatality of not only the operating person(s) but also the bystanders.
Therefore, there is a need for an automated racking system for a circuit breaker that enhances the operating safety and alleviates the abovementioned problems.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide an automated racking system for a circuit breaker.
Another object of the present disclosure is to provide a system that facilitates an operating personnel to perform the circuit breaker racking operation remotely by providing commands through a mobile application or a through a Human Machine Interface (HMI).
Still another object of the present disclosure is to provide a system that allows a circuit breaker to be racked out of a switchgear only when the breaker is in an open state, thereby ensuring operator safety and avoiding damage to the breaker and switchgear.
Yet another object of the present disclosure is to provide an automated racking system for a circuit breaker that allows the operator to stop the breaker movement at any point/position by providing such command through a mobile application or through a Human Machine Interface (HMI).
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages an automated system for racking a circuit breaker into and out of a switchgear panel. The switchgear panel has a mechanical interlock key with three positions viz. an intermediate position, a test position, and a service position. The system comprises a controller and a racking sub-system. The controller generates one or more operating command signals based on at least one command received from a user via a user interface. The command is indicative of a desired racking position of the circuit breaker. The racking sub-system is fixedly provided on the switchgear panel and communicatively coupled to the controller. The racking sub-system facilitates automatic racking of the circuit breaker from a current position to the desired position.
The racking sub-system comprises an interlock key motor, an interlock key motor driver, an interlock motor encoder mounted to the interlock key motor, a breaker racking motor, a racking motor driver, and a racking motor encoder mounted to the breaker racking motor. The interlock key motor driver receives a first operating command signal from the controller and operates the interlock key motor to turn the mechanical interlock key from a current position to the intermediate position. The interlock motor encoder generates a first feedback signal indicative of a current position of a shaft of the interlock key motor and transmits the first feedback signal to the controller through the interlock key motor driver. The racking motor driver receives a second operating command signal from the controller upon completion of rotation of the interlock key from the current position to the intermediate position and generates one or more actuating signals for the breaker racking motor to rack the circuit breaker into or out of the switchgear panel. The racking motor encoder generates a second feedback signal indicative of a physical position of the breaker in a breaker cubicle of the switchgear panel and transmits the generated second feedback signal to the controller to cause it to generate a third operating command signal for operating the interlock key motor and turning the mechanical interlock key from the intermediate position to the desired racking position. The controller detects the completion of rotation of the interlock key from intermediate position to the desired racking position based on the first feedback signal received from the interlock motor encoder.
In an embodiment, the controller comprises a reading module and a command processing module. The reading module receives the first and second feedback signals from the interlock motor encoder and the racking motor encoder via the interlock key motor driver and the racking motor driver respectively. The command processing module receives the commands from the user interface and the first and second feedback signals from the reading module. The command processing module generates (i) the first operating command signal based on the received commands to facilitate switching of the mechanical interlock key from the current position to the intermediate position, (ii) the second operating command signal based on the first feedback signals to activate the racking motor driver to facilitate the racking of the breaker, upon completion of mechanical interlock key rotation, and (iii) the third operating command signal based on the second feedback signal to switch the mechanical interlock key from the intermediate position to the desired position upon completion of the desired racking operation of the circuit breaker.
In an embodiment, the interface is a human machine user interface which facilitates the user to provide the at least one command and communicates with the controller to receive and display the current positions of the mechanical interlock key and the circuit breaker to the user based on the first and second feedback signals.
Alternatively, the user interface is a graphical user interface of an application 102 installed in an electronic device of the user, the graphical user interface being configured to facilitate the user to provide the at least one command. The application communicates with the controller to receive and display the current positions of the mechanical interlock key and the circuit breaker to the user based on the first and second feedback signals. The racking sub-system includes a communication module configured to receive the at least one command from the electronic device of the user. The communication module may be selected from the group consisting of a Bluetooth module, a Zigbee module, a Wi-Fi module, a Radio Frequency (RF) based communication module, a low-power wide-area network (LoRaWAN) module, a Near field Communication (NFC) module, and a cellular Internet of Things (IoT) module.
Advantageously, the racking motor driver generates the actuating signals for operating the breaker racking motor – (i) based on the second feedback signal, which is indicative of the physical position of the breaker in breaker cubicle of switchgear panel and is received from the racking motor encoder, and (ii) further based on a pre-determined set of rules defining an amount of torque required at the current position of circuit breaker to complete the desired racking operation.
Advantageously, the system facilitates the user to stop the breaker movement at any position.
Advantageously, the controller is configured to detect an abnormal condition during the breaker racking operation and generate an “error” prompt on the user interface to indicate the detected abnormal condition.
Advantageously, a power supply extension from the racking motor driver to the breaker racking motor is interlocked with the circuit breaker such that the power supply is extended to the breaker racking motor only when said circuit breaker is in an open state.
Advantageously, in one embodiment, the controller is configured to cooperate with the circuit breaker to determine the status of the breaker and is further configured to prevent the generation of the operating command signals if the breaker is found to be in closed state.
Advantageously, in an alternate embodiment, the controller is configured to cooperate with the circuit breaker to determine the status of the breaker and is further configured to disable a racking option on the user interface to prevent the user from providing the command for racking the breaker when the breaker is in the closed state.
The present invention further envisages a method for automatically racking a circuit breaker into and out of a switchgear panel.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
An automated racking system for a circuit breaker of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a block diagram of an automated racking system for a circuit breaker, in accordance with the present disclosure;
Figures 2A and 2B illustrate a flow diagram of a method for automatically racking a circuit breaker, in accordance with the present disclosure;
Figures 3A and 3B illustrate exemplary user interface screens depicting command options, statuses of circuit breaker and interlock key, and actual and/or set values of various parameters (such as speed, position, and time) of the system of Figure 1 for a 33kV vacuum circuit breaker; and
Figure 4 illustrates a schematic diagram depicting an interlock key motor and a breaker racking motor engaged with an interlock key and the circuit breaker respectively, in accordance with the present disclosure.
LIST OF REFERENCE NUMERALS
100 – System
10 – Switchgear panel
20 – Electronic device
30 – Circuit breaker
40 – Mechanical interlock key
50 – Breaker cubicle
101 – Racking sub-system
102 – Mobile/web application
104 – Communication module
106 – Human Machine Interface
108 – Controller
108a – Reading module
108b – Command processing module
110a – Interlock key motor driver
110b – Racking motor driver
112a – Interlock key motor
112b – Breaker racking motor
114a – Interlock motor encoder
114b – Racking motor encoder
402 – Base frame
404a – First connector
404b – Second connector
406a – Mechanical interlock key shaft
406b – breaker shaft
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
When an element is referred to as being “mounted on”, “engaged to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Conventionally, the circuit breakers are racked into or racked out of the switchgear manually as per a standard operating procedure (SOP). Typically, the procedure to rack the circuit breaker into or out of the switchgear requires an operator to insert a racking handle into a slot of a panel or an enclosure housing the circuit breaker and rotate it in clockwise or anti-clockwise direction. This puts the operator directly in front of the breaker enclosure. Therefore, the process of racking circuit breakers, particularly, the high-capacity circuit breakers (for e.g. 22kV to 33kV breakers) is wrought with danger to operating personnel’s safety as it may lead to undesirable/faulty conditions such as arc flash and cause a significant injury to the operating personnel, which is not desired.
In order to overcome the aforementioned problems, the present disclosure envisages an automated racking system (hereinafter referred to as “system 100”) for a circuit breaker and a method thereof (hereinafter referred to as “method 200”). The system 100 and method 200 are now being described with reference to Figure 1 through Figure 4.
Figure 1 shows the automated system 100 for racking a circuit breaker 30 into and out of a switchgear panel 10. The switchgear panel 10 has a mechanical interlock key 40 with three positions viz. an intermediate position, a test position, and a service position. The system 100 comprises a controller 108 and a racking sub-system 101. The controller 108 is coupled to a user interface and is configured to generate one or more operating command signals based on at least one command received from a user via the user interface. The user may be an operating personnel or a service and maintenance engineer. The command is indicative of a desired racking position of the circuit breaker 30.
The circuit breaker 30 may be racked in a ‘test position’ and a ‘service/connect’ position. In the test position, the electrical conductors of the circuit breaker 30 are disconnected from the corresponding busbars of the switchgear 10. Therefore, the circuit breaker 30 can be safely removed from the switchgear 10. In the service/connected position, the conductors of the circuit breaker 30 are connected to the corresponding busbars of the switchgear 10, allowing current to flow from a source, through the breaker 30, to one or more loads protected by the breaker 30.
The racking sub-system 101 is fixedly provided on the switchgear panel 10 and is communicatively coupled to the controller 108. The racking sub-system 101 receives the operating command signals and facilitates automatic racking of the circuit breaker 30 from a current position to the desired position based on the received signals.
The racking sub-system 101 comprises an interlock key motor 112a, an interlock key motor driver 110a, an interlock motor encoder 114a mounted to the interlock key motor 112a, a breaker racking motor 112b, a racking motor driver 110b, and a racking motor encoder 114b mounted to the breaker racking motor 112b.
In an embodiment, interlock key motor 112a may be engaged to a driving member of the mechanical interlock key 40. In an embodiment, referring to Figure 4, the interlock key motor 112a is coupled to a shaft 406a of the mechanical interlock key 40 through a first connector 404a.
The interlock key motor driver 110a is configured to receive a first operating command signal from the controller 108 and operate the interlock key motor 112a to turn the mechanical interlock key 40 from the current position to the intermediate position. The interlock motor encoder 114a is configured to generate a first feedback signal indicative of a current position of a shaft of the interlock key motor 112a and transmit the first feedback signal to the controller 108 through the interlock key motor driver 110a.
The controller 108 receives the first feedback signal. The controller 108 is configured to detect the completion of rotation of mechanical interlock key 40 from the current position to the intermediate position based on the received first feedback signal and generate a second operating command signal. The racking motor driver 110b is configured to receive the second operating command signal from the controller 108 and is further configured to generate one or more actuating signals for the breaker racking motor 112b to rack the circuit breaker 30 into or out of the switchgear panel 10.
In an embodiment with reference to Figure 4, the breaker racking motor 112b may be mounted on a slot, where a racking shaft/handle is typically inserted for manually racking the breaker 30. The breaker racking motor 112b may be coupled to a breaker shaft 406b through a second connector 404b. Upon receiving the actuating signals, the breaker racking motor 112b is configured to rotate the breaker shaft 406b in a clockwise or an anti-clockwise direction based on the desired racking position, to either rack the circuit breaker 30 into the switchgear panel 10 (i.e., rack the breaker 30 from test position to service position) or out of the switchgear panel 10 (i.e., rack the breaker 30 from service position to test position).
The breaker racking motor 112b and the racking motor encoder 114b are mounted on a base frame 402. The base frame 402 is connected to a door of a breaker cubicle 50 in such a way that the breaker racking motor shaft (not shown in figure) and breaker racking shaft 406b are aligned. Similarly, the interlock key motor 112a and the interlock motor encoder 114a are mounted on the base frame 402. The base frame 402 is connected to the breaker cubicle door in such a way that the interlock key motor shaft (not shown in figure) and the breaker interlock key shaft 406a are aligned. The base frame 402 is thus configured with through holes to allow the first and second connectors (404a, 404b) to pass therethrough.
The breaker racking motor 112b may be a servo motor or a stepper motor. The interlock key motor 112a may be selected from the group consisting of, but not limited to, a permanent magnet brush Direct Current (DC) motor, a DC brushless motor, a switched reluctance motor, a stepper motor, and a servo motor.
The racking motor encoder 114b is configured to generate a second feedback signal indicative of a physical position of the breaker 30 in the breaker cubicle 50 of the switchgear panel 10 and transmit the generated second feedback signal to the controller 108 through the racking motor driver 110b. The controller 108 detects completion of the breaker racking operation based on the second feedback signal and generates a third operating command signal to operate the interlock key motor 112a and turn the mechanical interlock key 40 from the intermediate position to the desired racking position. The controller 108 receives the first feedback signal from the interlock motor encoder 114a and detects the completion of rotation of the mechanical interlock key 40 from the intermediate position to the desired position based on the received first feedback signal.
In an embodiment, the controller 108 comprises a reading module 108a and a command processing module 108b. The reading module 108a is configured to receive the first and second feedback signals from the interlock motor encoder 114a and the racking motor encoder 114b via the interlock key motor driver 110a and the racking motor driver 110b respectively. The command processing module 108b is configured to receive the commands from the user interface and the first and second feedback signals from the reading module 108a. The command processing module 108b is configured to generate (i) the first operating command signal based on the received commands to facilitate switching of the mechanical interlock key 40 from the current position to the intermediate position, (ii) the second operating command signal based on the first feedback signal to activate the racking motor driver 110b to facilitate the racking of the breaker 30 upon completion of mechanical interlock key rotation, and (iii) the third operating command signal based on the second feedback signal to switch the mechanical interlock key 40 from the intermediate position to the desired position upon completion of the desired racking operation of the circuit breaker 30.
In an embodiment, the interface is a human machine user interface 106 configured to facilitate the user to provide the at least one command, and further configured to communicate with the controller 108 to receive and display the current positions of the mechanical interlock key 40 and the circuit breaker 30 to the user based on the first and second feedback signals.
Alternatively, the user interface is a graphical user interface of an application 102 installed in an electronic device 20 of the user, the graphical user interface being configured to facilitate the user to provide the at least one command. The application 102 can be configured to communicate with the controller 108 to receive and display the current positions of the mechanical interlock key 40 and the circuit breaker 30 to the user based on the first and second feedback signals. The racking sub-system 101 includes a communication module 104 configured to receive the at least one command from the electronic device 20 of the user. The communication module 104 may be selected from the group consisting of a Bluetooth module, a Zigbee module, a Wi-Fi module, a Radio Frequency (RF) based communication module, a low-power wide-area network (LoRaWAN) module, a Near field Communication (NFC) module, and a cellular Internet of Things (IoT) module.
Figures 3A and 3B show exemplary user interface screens. As shown in Figure 3A, the user interface shows a name of the feeder having the breaker 30 and options to rack in the circuit breaker 30 to service position and/or rack out the breaker 30 to test position, stopping the racking operation at any position, and acknowledgement of breaker rack in or rack out after successful completion of said operations. The user interface further includes a pictorial representation of the circuit breaker position and real-time values of motor revolutions/position (rev), motor speed (RPM), motor torque (Nm), and time elapsed from the start of a racking operation.
The controller 108 may be implemented using one or more general-purpose processors, Field Programmable Gate Arrays (FPGAs), Programmable Logic Controllers (PLCs), Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), microprocessors, microcontrollers, or state machines. The controller 108 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The controller 108 may be configured to retrieve data from and/or write data to a memory. The memory may be, for example, a random-access memory (RAM), a memory buffer, a hard drive, a database, an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), a read only memory (ROM), a flash memory, a hard disk, a floppy disk, cloud storage, and/or so forth.
Advantageously, the racking motor driver 110b is configured to generate the actuating signals for operating the breaker racking motor 112b based on the second feedback signals, indicative of the position of the breaker racking motor shaft, received from the racking motor encoder 114b and further based on a pre-determined set of rules defining an amount of torque required at the current position of circuit breaker 30 to complete the desired racking operation.
Advantageously, the rack in and rack out operations may be divided into different zones based on the amount of torque required during different stages of said operations. The racking motor driver 110b may generate actuating signals for operating the breaker racking motor 112b based on the zone of the racking operation.
For example, the rack in operation may be divided into the following three zones -
Zone 1 – may be between the breaker Rack-Out Position & the door interlock disengage position. In this zone, the torque demand is slightly higher as it is engaged mechanically, and the breaker 30 must move from steady state.
The position of Zone 1 is around 0-3 revolutions (from the fully Rack out position).
Zone 2 – This is a free running zone, from zone 1 position to near contact closing position including shutter opening.
This zone has lowest torque setting with constant speed. During manual operation, when there is an obstacle in the path like forgotten tools, nuts, washers etc. or shutter jam, it will block the trolley and it may derail trolley.
This situation can be avoided using Intelligent Remote Racking Device (IRRD) as it immediately trips off on high torque.
Zone 3 – This zone starts with fix and moving contact closing. This zone has maximum torque setting based on rating of the circuit breaker 30.
Advantageously, referring to Figure 3A, the system 100 facilitates the user to stop the breaker movement at any position. The breaker movement may be stopped at any position in case of an abnormality with the help of a “STOP” option provided on the application interface or HMI.
When the user clicks on the ‘stop’ option, either of the following two prompts may appear -
i. Recall to Rack out position – If the breaker 30 is moving from test position to service position, upon clicking this prompt, the system 100 brings the breaker 30 back to the test position (which is the original position of the breaker 30); and
ii. Recall to Rack in position – if the breaker 30 is moving from service position to test position, upon clicking this prompt, the system 100 brings the breaker 30 back to the service position (which is the original position of the breaker).
Advantageously, the controller 108 is configured to detect an abnormal condition during the breaker racking operation and generate an “error” prompt on the user interface to indicate the detected abnormal condition. For example, the interface may generate a “Rack in error” prompt on the screen (see Figure 3A) if either torque or time is exceeded due to any problem while breaker movement.
Advantageously, the system 100 may provide an additional safety feature of electrical interlocking, wherein a power supply extension from the motor driver 110b to the breaker racking motor 112b is interlocked with the circuit breaker 30 such that the power supply is extended to the breaker racking motor 112b only when the circuit breaker 30 is in an open state. This prevents racking out of the breaker 30 when it is in closed condition. To enable this feature, a contact (preferably, normally closed contact) of the breaker 30 is used for supply extension to the racking motor 110. This causes the power supply to be extended to the racking motor 110 only when the breaker 30 is in an open state/position. If the breaker 30 is found to be in closed state, the racking motor driver 110b will not extend supply to the breaker racking motor 112b.
In addition to this, the controller 108 is configured to cooperate with the circuit breaker 30 to determine the status of the breaker 30 (i.e., closed or open state). To achieve this, a contact of the breaker 30 may be extended to the controller 108. The controller 108 may be configured to determine the breaker status based on the state (i.e., open or closed) of the contact.
In one embodiment, the controller 108 is configured to prevent the generation of operating command signals if the breaker 30 is found to be in closed state, even when a command for racking the circuit breaker 30 is received from the user via the user interface (102/106).
In an alternate embodiment, the controller 108 is configured to disable/block a racking option on the user interfaces (102, 106) to prevent the user from providing the command for racking the breaker 30 when the breaker 30 is in the closed state.
The above features ensure operator safety and avoid damage to the breaker 30 and switchgear panel 10.
Figures 2A and 2B illustrate the method 200 for automatically racking a circuit breaker 30 into and out of a switchgear panel 10, wherein the switchgear panel 10 is provided with a mechanical interlock key 40 with an intermediate position, a test position, and a service position. The method 200 comprises the following steps:
At step 202, a controller 108 receives at least one command, indicative of a desired racking position of the circuit breaker 30, via a user interface.
At step 204, the controller 108 generates a first operating command signal based on the received command.
At step 206, an interlock key motor driver 110a of a racking sub-system 101 that is fixedly provided on the switchgear panel 10 receives the first operating command signal from the controller 108.
At step 208, the interlock key motor driver 110a operates an interlock key motor 112a to turn the mechanical interlock key 40 from a current position to the intermediate position.
At step 210, an interlock motor encoder 114b mounted to the interlock key motor 112a generates a first feedback signal indicative of a current position of a shaft of the interlock key motor 112a.
At step 212, the interlock motor encoder 114b transmits the first feedback signal to the controller 108 through the interlock key motor driver 110a.
At step 214, the controller 108 detects the completion of rotation of the interlock key 40 from the current position to the intermediate position based on the first feedback signal.
At step 216, the controller 108 generates a second operating command signal upon the detection of completion of rotation of the interlock key 40 from the current position to the intermediate position.
At step 218, the racking motor driver 110b receives the second operating command signal from the controller 108.
At step 220, the racking motor driver 110b generates one or more actuating signals for the breaker racking motor 112b to rack the circuit breaker 30 into or out of the switchgear panel 10.
At step 222, a racking motor encoder 114b mounted to the breaker racking motor 112b generates one or more second feedback signals indicative of a physical position of the breaker 30 in a breaker cubicle 50 of switchgear panel 10.
At step 224, the racking motor encoder 114b transmits the generated second feedback signals to the controller 108 through the racking motor driver 110b.
At step 226, the controller 108 generates a third operating command signal for operating the interlock key motor 112a and turning the mechanical interlock key 40 from the intermediate position to the desired racking position, upon completion of racking of the circuit breaker 30.
At step 228, the controller 108 detects completion of rotation of the interlock key 40 from the intermediate position to the desired racking position based on the first feedback signal.
In an exemplary operative embodiment, when a command to rack-in the breaker 30 from the test position to the service position is given through the application 102 or 106 , the application 102 or 106 prompts the user to confirm the given command by selecting ‘Yes’ or ‘No’. After confirmation by the user, the application interface displays “START RACK-IN” to the user. A confirmation pop up again appears on the display screen for receiving final confirmation from the user before starting the rack in operation. Upon confirmation, the interlock key motor 112a turns the mechanical interlock key 40 from ‘test position’ to ‘intermediate position’ and then stops. Then the breaker racking motor 112b rotates the shaft in clockwise direction to rack in the breaker 30. Once the breaker 30 is fully racked into the switchgear 10, the interlock key motor 112a rotates the key 40 from the ‘intermediate position’ to the ‘service position’. Once the breaker 30 is successfully racked into the switchgear 10, the application interface displays “RACK IN COMPLETED ACK” on the display screen of the electronic device 20.
In another exemplary operative embodiment, when a command to rack-out the breaker 30 from the ‘service position’ to the ‘test position’ is given through the application 102 or 106, the application 102 or 106 prompts the user to confirm the given command by selecting ‘Yes’ or ‘No’. After confirmation by the user, the application interface displays “START RACK-OUT” to the user. A confirmation pop up again appears on the display screen for receiving final confirmation from the user before starting the rack out operation. Upon confirmation, the interlock key motor 112a turns the mechanical interlock key 40 from ‘service position’ to ‘intermediate position’ and then stops. Then the breaker racking motor 112b rotates the shaft in anti-clockwise direction to rack out the breaker 30 from the switchgear 10. Once the breaker 30 is fully racked out of the switchgear 10, the interlock key motor 112a rotates the key 40 from the ‘intermediate position’ to the ‘test position’. Once the breaker 30 is successfully racked out of the switchgear 10, the application interface displays “RACK OUT COMPLETED ACK” on the display screen of the electronic device 20.
The system 100 of the present disclosure was implemented and tested. The components of the system 100 with the following specifications were selected for its implementation.
The controller 108 was implemented using a PLC controller. A power was supplied to the PLC controller via an AC/DC converter having following specifications.
Description AC/DC CONVERTER 24V 60W
Current - Output (Max) 2.5A
Power (Watts) 60W
Voltage – Input 100- 240V AC
Voltage - Output 1 24V

The PLC controller had the following specifications.
PLC for Breaker and interlock key movement
Power input 24V
COM-1 USB Programming port
COM-2 & 3 RS 485 communication- for HMI/ VFD
Ethernet Port To Link the PLC with HMI display /SERVO/ SCADA.
Number of Inputs and Type 8 digital inputs
Number of Outputs and Type 4 digital outputs
The interlock key motor 112a was implemented using a servo motor having the following specifications.
Motor specifications for Key movement
AC Servo Motor
Input 3 phase AC 76 V 1.1A
Rated output 0.1kW
Rated frequency 50Hz
Rated Revolutions 3000 rpm/ min
Cont. Torque 0.32 N-m
The driver 110a for the interlock key motor 112a was selected to have the following specifications.
AC servo Driver for Key movement
Input Output
Voltage 200-240V 0-240V
Phase 1 phase/ 3phase 1 phase/ 3 phase
F.L.C 1.6A/ 0.9 A 1.2A
Frequency 50/60 Hz 0-541.7 Hz
Power 100W

Similarly, the breaker racking motor 112b and the corresponding motor driver 110b were selected to have the following specifications -
Motor specifications for Breaker movement
Pn 400W
Mn 1.27Nm
I max 7.8A
In 2.6A
Un 220V
Nm 3000 U/Min

AC servo drive for Breaker movement
Input Output
Voltage 200 to255 V single phase
170 to 255 V three phase 0-240V
Phase 1 phase/ 3phase 1 phase/ 3phase
F.L.C 1.6A/ 0.9 A 2.6A
Frequency 50/60 Hz 0-541.7 Hz
Power 400 W at 220 V

The breaker racking motor 112b and the interlock key motor 112a were coupled to gear box assemblies having the following specifications -
Gear box
Gear box for 400w motor 1:20 ratio planetary
Gear box for 100w motor 1:10 ratio planetary

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an automated racking system for a circuit breaker that and a method thereof that:
• facilitates an operating personnel to perform the circuit breaker racking operation remotely by providing commands through a mobile application or through a Human Machine Interface (HMI);
• allows automatic racking out of circuit breaker only when the circuit is in open state, thereby ensuring operator safety and avoiding damage to the breaker and switchgear; and
• allows the operator to stop the breaker movement at any point with the help of the application interface or the HMI.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of devices, articles, or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation
,CLAIMS:WE CLAIM:
1. An automated system (100) for racking a circuit breaker (30) into and out of a switchgear panel (10), said switchgear panel (10) having a mechanical interlock key (40) with an intermediate position, a test position, and a service position, said system (100) comprising:
a. a controller (108) configured to generate one or more operating command signals based on at least one command received from a user via a user interface, said command indicative of a desired racking position of the circuit breaker (30);
b. a racking sub-system (101) fixedly provided on the switchgear panel (10) and communicatively coupled to said controller (108), said racking sub-system (101) comprising:
i. an interlock key motor (112a);
ii. an interlock key motor driver (110a) configured to receive a first operating command signal from said controller (108) and operate said interlock key motor (112a) to turn the mechanical interlock key (40) from a current position to the intermediate position;
iii. an interlock motor encoder (114a), mounted to said interlock key motor (112a), configured to generate a first feedback signal indicative of a current position of a shaft of the interlock key motor (112a) and transmit said first feedback signal to said controller (108) through said interlock key motor driver (110a);
iv. a breaker racking motor (112b);
v. a racking motor driver (110b) configured to receive a second operating command signal from said controller (108) upon completion of rotation of said interlock key (40) from the current position to the intermediate position and further configured to generate one or more actuating signals for said breaker racking motor (112b) to rack the circuit breaker (30) into or out of the switchgear panel (10); and
vi. a racking motor encoder (114b), mounted to said breaker racking motor (112b), configured to generate a second feedback signal indicative of a physical position of the breaker (30) in a breaker cubicle (50) of the switchgear panel (10) and transmit the generated second feedback signal to said controller (108) to cause it to generate a third operating command signal, for operating said interlock key motor (112a) and turning the mechanical interlock key (40) from the intermediate position to the desired racking position, upon completion of racking of the circuit breaker (30).
2. The system (100) as claimed in claim 1, wherein said controller (108) comprises:
a. a reading module (108a) configured to receive said first and second feedback signals from said interlock motor encoder (114a) and said racking motor encoder (114b) via said interlock key motor driver (110a) and said racking motor driver (110b) respectively;
b. a command processing module (108b) configured to receive said commands from said user interface and said first and second feedback signals from said reading module (108a), said command processing module (108b) configured to generate:
i. said first operating command signal based on said received commands to facilitate switching of the mechanical interlock key (40) from the current position to the intermediate position;
ii. said second operating command signal based on said first feedback signals to activate the racking motor driver (110b) to facilitate the racking of the breaker (30), upon completion of mechanical interlock key rotation; and
iii. said third operating command signal based on said second feedback signal to switch the mechanical interlock key (40) from the intermediate position to the desired position upon completion of the desired racking operation of the circuit breaker (30).
3. The system (100) as claimed in claim 1, wherein said user interface is a human machine user interface (106) configured to facilitate the user to provide said at least one command, and further configured to communicate with said controller (108) to receive and display the current positions of said mechanical interlock key (40) and the circuit breaker (30) to the user based on said first and second feedback signals.
4. The system (100) as claimed in claim 1, wherein said user interface is a graphical user interface of an application (102) installed in an electronic device (20) of the user, said graphical user interface configured to facilitate the user to provide said at least one command, said application (102) configured to communicate with said controller (108) to receive and display the current positions of said mechanical interlock key (40) and the circuit breaker (30) to the user based on said first and second feedback signals.
5. The system (100) as claimed in claim 4, wherein said racking sub-system (101) includes a communication module (104) configured to receive said at least one command from the electronic device (20) of the user, said communication module (104) being selected from the group consisting of a Bluetooth module, a Zigbee module, a Wi-Fi module, a Radio Frequency (RF) based communication module, a low-power wide-area network (LoRaWAN) module, a Near field Communication (NFC) module, and a cellular Internet of Things (IoT) module.
6. The system (100) as claimed in claim 1, wherein said racking motor driver (110b) is configured to generate said actuating signals for operating said breaker racking motor (112b) based on:
a. said second feedback signal, indicative of the physical position of the breaker in the breaker cubicle (50) of the switchgear panel (10), received from said racking motor encoder (114b); and
b. a pre-determined set of rules defining an amount of torque required at the current position of circuit breaker (30) to complete the desired racking operation.
7. The system (100) as claimed in claim 1, which facilitates the user to stop the breaker movement at any position.
8. The system (100) as claimed in claim 1, wherein said controller (108) is configured to detect an abnormal condition during the breaker racking operation and generate an “error” prompt on the user interface to indicate the detected abnormal condition.
9. The system (100) as claimed in claim 1, wherein a power supply extension from said motor driver (110b) to said breaker racking motor (112b) is interlocked with the circuit breaker (30) such that the power supply is extended to the breaker racking motor (112b) only when said circuit breaker (30) is in an open state.
10. The system (100) as claimed in claim 1, wherein said controller (108) is configured to cooperate with the circuit breaker (30) to determine the status of the breaker (30) and is further configured to prevent the generation of the operating command signals if the breaker is found to be in closed state.
11. The system (100) as claimed in claim 1, wherein said controller (108) is configured to cooperate with the circuit breaker (30) to determine the status of the breaker (30) and is further configured to disable a racking option on said user interface to prevent the user from providing the command for racking the breaker (30) when the breaker (30) is in the closed state.
12. A method (200) for automatically racking a circuit breaker (30) into and out of a switchgear panel (10), said switchgear panel (10) having a mechanical interlock key (40) with an intermediate position, a test position, and a service position, said method (200) comprising:
a. receiving (202), by a controller (108), at least one command, indicative of a desired racking position of the circuit breaker (30), via a user interface;
b. generating (204), by said controller (108), a first operating command signal based on said received command;
c. receiving (206), by an interlock key motor driver (110a) of a racking sub-system (101) fixedly provided on the switchgear panel (10), said first operating command signal;
d. operating (208), by said interlock key motor driver (110a), an interlock key motor (112a) to turn the mechanical interlock key (40) from a current position to the intermediate position;
e. generating (210), by an interlock motor encoder (114b) mounted to said interlock key motor (112a), a first feedback signal indicative of a current position of a shaft of the interlock key motor (112a);
f. transmitting (212), by said interlock motor encoder (114b), said first feedback signal to said controller (108) through said interlock key motor driver (110a);
g. detecting (214), by said controller (108), the completion of rotation of said interlock key (40) from the current position to the intermediate position based on said first feedback signal;
h. generating (216), by said controller (108), a second operating command signal upon the detection of completion of rotation of said interlock key (40) from the current position to the intermediate position;
i. receiving (218), by a racking motor driver (110b), said second operating command signal from said controller (108);
j. generating (220), by said racking motor driver (110b), one or more actuating signals for said breaker racking motor (112b) to rack the circuit breaker (30) into or out of the switchgear panel (10);
k. generating (222), by a racking motor encoder (114b) mounted to said breaker racking motor (112b), a second feedback signal indicative of a physical position of the breaker (30) in a breaker cubicle (50) of the switchgear panel (10);
l. transmitting (224), by said racking motor encoder (114b), the generated second feedback signal to said controller (108) through said racking motor driver (110b);
m. generating (226), by said controller (108), a third operating command signal based on said received feedback signal, for operating said interlock key motor (112a) and turning the mechanical interlock key (40) from the intermediate position to the desired racking position, upon completion of racking of the circuit breaker (30); and
n. detecting (228), by said controller (108), the completion of rotation of said interlock key (40) from the intermediate position to the desired racking position based on said first feedback signal.

Dated this 10th day of November, 2021

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI