Source: Polaris Electric People
KYN28 high-voltage switchgear refers to the electrical products used in power system power generation, transmission, distribution, power conversion and consumption to play the role of on-off, control or protection, with a voltage level of 12kV, mainly including high-voltage circuit breakers, grounding switches, transformers, etc. The high-voltage switchgear manufacturing industry is an important part of the power transmission and transformation equipment manufacturing industry, and occupies a very important position in the entire power industry. Debugging is generally a routine process to test the safety and stability of the equipment before the components are replaced or the equipment is put back into use.
First, we will give a brief introduction to the high-voltage switchgear to understand the corresponding precautions.
The high-voltage metal-enclosed switchgear is composed of two parts: the cabinet and the handcart. The cabinet is divided into four separate compartments by metal partitions: bus room, circuit breaker trolley room, cable room and relay instrument room. Hand car according to the use is divided into circuit breaker hand car, metering hand car, isolation hand car, etc., the same parameter specifications of the hand car can be freely interchanged, the hand car in the cabinet has a test position and a working position, each position has a device in place, to ensure that the interlock is reliable. The high-voltage switchgear has a safe and reliable interlocking device, which can meet the requirements of "five preventions":
1. Prevent misoperation of the circuit breaker;
2. Prevent the load from pulling and closing the isolation switch, that is, to prevent the load from pushing and pulling the trolley;
3. Prevent live hanging grounding wire, that is, prevent live connection grounding switch;
4. Prevent power transmission with grounding wire, that is, prevent power transmission when the grounding switch is in the grounding position;
5. Prevent inadvertently entering the live interval.
When the circuit breaker handcart is in the test or working position, the circuit breaker can be closed and separated, and after the circuit breaker is closed, the handcart cannot move, which prevents the load from being pulled and pushed by mistake.
Only when the grounding switch is in the open position, the circuit breaker handcart can be moved from the test position to the working position, and only when the circuit breaker handcart is in the test position, the grounding switch can be closed, so as to prevent the live mis-closing of the grounding switch and prevent the grounding switch from closing when the grounding switch is in the closed position.
When the grounding switch is in the open position, the lower door and the rear door cannot be opened, preventing the live interval from being mistakenly entered.
When the circuit breaker is in the working position, the secondary plug is locked and cannot be pulled out. In order to ensure the safety and the reliability of each interlock device from damage, it must be operated according to the interlock anti-misoperation procedure.
Second, the seven steps of the main power cabinet power transmission operation
1. Close and lock all cabinet doors and rear seals.
2. Push on the transfer trolley and position it, push the circuit breaker trolley into the cabinet and position it in the test position, when pushing the circuit breaker, you need to press the two push and pull handles of the circuit breaker to the middle, and at the same time push forward (push into the cabinet), after the circuit breaker reaches the test position, let go of the push and pull handle, and the handle should be automatically reset. Manually plug in the aero plug, close the handcar compartment door and lock it.
3. Observe whether the instruments and signal indications of the upper cabinet door are normal. (If all the indicators are not on, open the cabinet door and confirm whether the bus power switch is closed, if the indicators are still not lit, the control loop needs to be overhauled.) ）
4. Insert the crank handle of the circuit breaker handcart into the jack of the crank and press down hard, turn the crank clockwise, about 20 turns, and remove the crank handle when the crank is obviously blocked and accompanied by a "click" sound, at this time the handcart is in the working position, the aviation plug is locked, and the main circuit of the circuit breaker handcart is turned on to check the relevant signal. (Due to the mechanical interlocking of the main power supply and the standby power supply, when the main power circuit breaker is in the working position, the standby power circuit breaker must be in the experimental position)
5. Observe the live display to make sure that the external power supply has been sent to the cabinet. (The display light on the panel of the live display indicates that the external power supply has been sent to the lower contact of the circuit breaker of this cabinet.) If the live indicator light is not on, you need to send an external power supply to the cabinet first. ）
6. Close the transfer switch to close the circuit breaker and send power, at the same time, the red closing indicator light on the instrument door is on, and the green opening indicator light is off, check other relevant signals, everything is normal, and the power transmission is successful. (When operating the transfer switch of division and closing, rotate the operating handle clockwise to the indicated closing position of the panel, and the operating handle should automatically reset to the pre-closing position after releasing the hand.) ）
7. If the circuit breaker is automatically opened after closing or during operation, it is necessary to judge what kind of fault and eliminate it before re-transmitting the power according to the above procedures. (When the line fault circuit breaker is opened, an audible and visual alarm will be issued, that is, the red fault indicator light on the panel will be lit, and the fault of the signal screen will sound at the same time.) At this time, observe the comprehensive relay, if the protection trip light is on, the fault is the line overcurrent, in the fault maintenance can be pressed the signal screen reset button to cancel the sound, after the maintenance is completed, you need to press the comprehensive relay panel reset button manually. ）
3. Five steps of power failure operation of the main power cabinet
1. Observe all cabinet related signals and confirm that all outlet cabinet circuit breakers are in the open position.
2. The transfer switch makes the circuit breaker open and power off, and the red closing indicator on the instrument door is off at the same time, and the green opening indicator light is on, check other relevant signals, everything is normal, and the power failure is successful. (When operating the closing and dividing transfer switch, rotate the operating handle counterclockwise to the indicated position on the panel, and the operating handle should automatically reset to the pre-divided position after releasing the hand.) ）
3. Insert the crank handle of the circuit breaker handcart into the crank socket and press down hard, turn the crank counterclockwise, about 20 turns, remove the crank when the crank is obviously blocked and accompanied by a "click" sound, at this time the handcart is in the test position, the aviation plug lock is released, open the door of the handcar room, and manually disengage from the aviation plug. (The main circuit of the hand hand is disconnected)
4. Observe the live display and confirm that it is not charged before continuing the operation. (The lower door of the inlet cabinet is forced to lock by electromagnetic lock, which can only be unlocked when the incoming end is not electrified, but it can also be unlocked with a key when the inlet end is live.) The opening of the incoming circuit breaker does not mean that the incoming cabinet is not electrified, if the external power supply is not stopped, the cable room is with high voltage at this time, and it is life-threatening to forcibly enter. ）
5. Open the lower door, check the electricity (must check the electricity), discharge (must discharge), hang the ground wire (must hang the ground wire), and the maintenance personnel can enter the maintenance and overhaul.
Fourth, the operating procedures of the standby power cabinet are the same as those of the main power cabinet. Since the relevant content has been introduced earlier, that is, the seven steps of power transmission operation and the five steps of power outage operation, we will not repeat it.
Fifth, the three steps of the operation of the metering cabinet
1. The metering handcart is directly connected by dynamic and static contacts, and does not have the ability to break and extinguish the arc, and must not be shaken in and out of the metering handcart with load.
2. The metering handcart and the incoming switchgear circuit breaker have electrical and mechanical interlocking, and the main power supply (standby power) circuit breaker can only be operated after the switch is opened, and the metering handcart can not be forcibly operated to avoid damage to the interlocking device. When the metering trolley is forcibly shaken out with load, the main power supply (standby power) circuit breaker will automatically open to avoid personal injury or death.
3. The method of shaking in and out of the metering handcart is the same as that of the circuit breaker handcart.
Sixth, the three steps of PT cabinet operation
1. Start by rocking into the PT hand car.
2. Observe the live display, if the display light is on, the 10KV high voltage has been sent to the cabinet, check whether the voltmeter is normal.
3. The method of shaking in and out of the PT handcart is the same as that of the circuit breaker handcart.
7. Seven steps of power transmission operation in the outlet cabinet
1. Close all cabinet doors and rear seals and lock them. (The door can be closed only when the grounding switch is in close position)
2. Insert the grounding switch operating handle into the hexagonal hole on the lower right side of the middle door, rotate counterclockwise, make the grounding switch in the open position, take out the operating handle, and the interlocking plate at the operation hole will automatically pop back, cover the operation hole, and lock the lower cabinet door.
3. Push on the transfer trolley and position it, push the circuit breaker trolley into the cabinet and position it in the test position, (when pushing the circuit breaker, you need to press the two push-pull handles of the circuit breaker to the middle, and at the same time push forward (push into the cabinet), after the circuit breaker reaches the test position, let go of the push-pull handle, and the handle should be automatically reset. Manually plug in the aero plug, close the handcar compartment door and lock it.
4. Observe whether the indicators and numbers of the upper cabinet door are normal. (Under normal circumstances, the integrated relay power supply light is on, the circuit breaker opening indicator light and the energy storage indicator light are on, the grounding opening indicator light is on, if all the indicators are not on, then open the upper cabinet door to confirm whether the bus power switch is closed, if the indicators are still not lit, the control loop needs to be overhauled.) ）
5. Insert the crank handle of the circuit breaker handcart into the crank socket and press down hard, turn the crank clockwise, about 20 turns, and remove the crank handle when the crank is obviously blocked and accompanied by a "click" sound, at this time the handcart is in the working position, the aviation plug is locked, and the circuit breaker handcar owner circuit is turned on to check the relevant signal.
6. Operate the instrument door to close and disconnect the transfer switch to close the circuit breaker and send power, at the same time, the red closing indicator light on the instrument door is on, the green opening indicator is off, check the live display and other related signals, everything is normal, and the power transmission is successful. (When operating the closing and sub-transfer switches, rotate the operating handle clockwise to the indicated closing position of the panel, and the operating handle should automatically reset to the pre-closing position after releasing the hand.) If it cannot be closed normally, check whether the transformer door is closed.
7. If the circuit breaker is automatically opened after closing or during operation, it is necessary to judge what kind of fault and eliminate it before re-transmitting the power according to the above procedures. (When the line fault circuit breaker is opened, it will send out an audible and visual alarm, and the fault sound will sound at the same time.) At this time, observe the comprehensive relay, if the protection trip light is on, the fault is the line overcurrent, after the maintenance is completed, you need to press the comprehensive relay panel reset button manually. ）
8. Six steps of power outage operation of outlet cabinet
1. Operate the instrument door to close and disconnect the transfer switch to make the circuit breaker open and lose power, and at the same time, the red closing indicator light on the instrument door is off, and the green opening indicator light is on, check other relevant signals, everything is normal, and the power failure is successful. (When operating the closing and dividing transfer switch, rotate the operating handle counterclockwise to the indicated position on the panel, and the operating handle should automatically reset to the pre-divided position after releasing the hand.) ）
2. Insert the crank handle of the circuit breaker handcart into the crank socket and press down hard, turn the crank counterclockwise, about 20 turns, remove the crank when the crank is obviously blocked and accompanied by a "click" sound, at this time the handcart is in the test position, the aviation plug lock is released, open the door of the handcar room, and manually disengage from the aviation plug. (The main circuit of the hand hand is disconnected)
3. Push on the transfer trolley and lock it, pull out the circuit breaker trolley to the transfer trolley, and remove the transfer trolley. (When pulling the circuit breaker, you need to press the two push-pull handles of the circuit breaker to the middle, and at the same time pull back hard (pull out of the cabinet), after the circuit breaker is pulled to the transfer trolley and in place, let go of the push-pull handle, and the handle should be automatically reset.) )
4. Observe the live display and confirm that it is not charged before continuing the operation.
5. Insert the grounding switch operating handle into the hexagonal hole on the lower right side of the middle door, rotate clockwise, make the grounding switch in the closing position, confirm that the grounding switch has been closed, open the lower door of the cabinet, and the maintenance personnel can enter the maintenance and overhaul.
6. The grounding switch and the circuit breaker and the cabinet door are interlocked, only when the circuit breaker is in the test position or withdrawn from the cabinet can the grounding switch be closed, and only after the grounding switch is opened, the circuit breaker can be shaken from the test position to the working position, and cannot be forcibly operated. The grounding switch and the lower cabinet door interlock can be unlocked urgently, and it can be unlocked urgently only if it is confirmed that it is necessary, otherwise there is a risk of electric shock.
9. The relevant content of electrical and mechanical interlocking
1. Mains power and standby power
The main power supply (standby power supply) circuit breaker is equipped with electrical and mechanical interlocking, and the two circuit breakers cannot be closed at the same time, and when the main power circuit breaker is in the working position, the standby power supply can only be in the experimental position and cannot be closed. The reverse is the same.
2. Main power supply (standby power) circuit breaker and metering trolley
Only the metering handcart is in the working position, the main power supply (standby power supply) circuit breaker can be closed, after the circuit breaker is closed, it is not allowed to shake out the metering handcart with load, when the misoperation of the pre-shake metering handcar, the circuit breaker will trip immediately, and the signal screen alarm.
3. Outlet cabinet and transformer
The outlet cabinet and the transformer are equipped with an electrical interlock, when the transformer door is fully closed, the outlet cabinet can be closed, if one of the doors is not closed, or all are not closed, the outlet cabinet can not be closed.
4. Outlet cabinet circuit breaker and grounding switch
When the outlet cabinet is in the closing position, because it is equipped with a mechanical interlock with the grounding switch, the grounding knife can not be closed, and the grounding switch can be closed only when the circuit breaker is in the open state and is in the test position.