1. Basic requirements of relay protection The basic meaning is that when the protection device is moving, only the fault element is removed from the power system, so as to reduce the scope of power failure, so as to ensure the safe operation of the non-fault part of the system. Quick activity means that the relay protection device should disconnect the fault element as fast as possible. In this way, the damage degree of the faulty equipment can be reduced, the user working time at low voltage can be reduced, and the stability of the power system can be improved. The ability of a sensitivity protection device to respond to failure or abnormal operating conditions within its protection range is called sensitivity (sensitivity). Sensitivity is commonly measured by the sensitivity coefficient. It is determined in the action value of the measuring element of the protection device, according to the most unfavorable operation mode, fault type, the point within the protection range to check, and meet the relevant standards. Reliability Reliability refers to the fact that in the protection device, the protection device should act reliably when the fault it should react occurs (i. e., no rejection).
2. The relay protection device in operation shall be inspected according to the following items: mechanical part inspection and electrical characteristic test of the relay; measurement of insulation resistance of the secondary circuit; secondary electrification test; and whole operation test of the protection device.
3. Operation procedures for relay protection and calibration. The relay protection test requires two operations, one monitoring and one operation. The relay protection calibration operation should check the integrity of the test instrument before doing the test. The middle voltage cabinet circuit breaker must be in the test position.
Contents of periodic verification of relay protection
1.Abstract: Relay protection device periodic calibration system Chapter of relay protection and safety automatic device (referred to as "relay protection device") inspection work is the technical means and effective measures to ensure the correct action of relay protection.
2. Content and cycle of periodic inspection Regular inspection shall be carried out according to the cycle stipulated in this standard, projects and the contents of the standardized operation instructions approved by the competent authorities at all levels. The formulation of the periodic inspection cycle plan should comprehensively consider the voltage level and working condition of the equipment under its control, and carry out according to the cycle and project required by this standard.
3. In order to protect the relay protection device to act reliably, the relay protection device and the secondary circuit should usually be checked or verified regularly. The general check and inspection cycle is one year. Relay protection and secondary circuit In case of power failure, check and verify the electrical components and secondary circuit. Mainly should do the following content:, relay to the mechanical without distinction
4. In order to ensure that the relay protection device can act reliably in the case of the failure of the power system, the relay protection device and the secondary circuit in operation shall be checked regularly. Usually, the relay protection device of the 10 kV power system should be checked once every two years;
5. The relay protection team shall be equipped with at least the following instruments and instruments: DL / T 955-200 pointer voltage, ammeter, digital voltage, ammeter, clamp ammeter, phase meter, millisecond meter, bridge; 500V, 1000V and 2500V Metameter; memorable oscilloscope; high frequency oscillator and frequency meter required for carrier channel test, non-inductive resistance, variable attenuator, etc.;
6. Relay protection inspection and management system. The regular inspection and inspection system is the guarantee to improve the quality of protection and verification, and puts forward clear provisions for the newly operational and operational protection devices from the inspection cycle to the inspection specifications. The verification process shall refer to the Inspection Regulations on Relay Protection and Power Grid Safety Automatic Device " and the specific inspection procedures.