Source: Centralized Control House
First, the classification of protective pressure plates
Hard platen: Hard platen refers to hardware equipment such as connecting pieces in the protective cabinet, such as the protective platen of the transformer group, the protective platen of the start-up transformer, the line of the booster station and the protective platen of the contact transformer.
Soft pressure plate: refers to the surrender of a certain function of the software system of the protection device, such as putting in and exiting a certain protection and control function, which can be realized by modifying the software control logic of the protection device, such as the grounding protection of the rotor.
2. How to distinguish between the outlet pressure plate and the functional pressure plate?
The protective pressure plate is divided into an outlet pressure plate and a functional pressure plate.
The functional pressure plate is to realize the function of the protection device (such as: differential protection, zero sequence protection, re-pressure over-current protection, etc.).
The outlet pressure plate determines the final result of the protection action.
The outlet pressure plate comprises a trip outlet pressure plate and a starting pressure plate.
The trip outlet pressure plate is directly applied to the switch that needs to be tripped; For example, the main valve is closed, the jump and demagnetization switch pressure plate, etc., which is a DC 220V strong voltage board.
The starting pressure plate is used as an opening for other protections; Such as: starting failure pressure plate, starting standby branch quick cut, locking on-load voltage regulating pressure plate, etc., is a 24V weak voltage board.
Take the protection screen of the generator and transformer group of unit #1 of our factory as an example: red is the tripping outlet pressure plate, yellow is the starting pressure plate, and gray is the backup pressure plate.
3. Precautions when casting protective pressure plates
1. Check whether the tripping light of the protection device is lit and cannot be restored, otherwise it is possible that the contact of the protection trip outlet has been glued.
2. Switch the clamp ammeter to the "voltage level" and the "AC and DC conversion buttons to the DC DC level".
2. Measure the voltage of the upper and lower ports of the protective platen to the ground. The positive ground of the port under the outlet pressure plate is 0, and the negative facing ground of the upper port is not more than 110V. If there is no potential at both ends of the outlet pressure plate, check whether the switch has tripped or the control power supply has disappeared.
Only after the voltage at both ends of the protective platen is measured that there is no anopolarity, the platen can be put into the platen.