1. General provisions
1.0.1 This code is formulated with a view to implementing the related national technical-economic policies, to accomplishing state-of-the-art technology and economic feasibility in the design of relaying protection and automatic device of electric power installation.
1.0.2 This code is applicable to design of relaying protection and automatic device of electric power installations like 3~110kV power circuit or equipment, power generator with single-machine capacity of MW or below, 63MW?A or below power transformer.
1.0.3 For the design of relaying protection and automatic device of electric power installation, not only the requirements stipulated in this code but also those in the current relevant ones shall be complied with.
2. General rules
2.0.1 Electric equipment and circuit shall be installed with relaying protection and automatic device for the reaction short-circuit fault and abnormal operation. The relaying protection and automatic device shall be able to timely reflect the fault and abnormal operating condition of equipment and circuit, and shall excise fault and restore the power supply as soon as possible.
2.0.2 The electric equipment and circuit shall be provided with main protection, back protection and abnormal operation protection, and auxiliary protection may be added if necessary.
2.0.3 Relaying protection and automatic device shall meet the requirements of reliability, selectivity, sensitivity and quick-action, and they shall be in accordance with the following requirements:
1 The relaying protection and automatic device shall be possessed of automatic on-line measurement, blocking and device abnormity or fault alarm functions.
2 When there is cooperating requirement for adjacent equipment and circuit, the sensitivity factor and actuation time of the up and down levels shall be interacted.
3 When protection equipment and circuit go out of order within the protection domain, necessary sensitivity factor shall be possessed.
4 The protection device shall be able to excise short-circuit fault as early as possible. When it requires fast excising short-circuit fault, protection device may be allowed to act without selectivity, but it shall make use of automatic throw-in equipment of auto-reclose circuit breaker or standby power and standby equipment, so as to shrink the power blackout scope.
2.0.4 The sensitivity factor of the protection device shall be calculated according to unfavorable normal operation mode and unfavorable fault type. If necessary, impact of short-circuit current attenuation shall be taken into consideration. The minimum sensitivity factors of various relaying protection shall comply with the requirements of Annex B of this code.
3. Generator protection
3.0.1 The power generator with voltage of 3kV or above and capacity of 50MW or below shall be installed with corresponding protection devices for the following faults and abnormal operation modes:
1 Interphase short circuit of stator winding;
2 Stator winding grounding;
3 Turn-to-turn fault of stator winding;
4 External short circuit of power generator;
5 Overload of stator winding;
6 Overvoltage of stator winding;
7 Overload of rotor surface layer (loading);
8 Excitation circuit grounding;
9 Exciting current abnormally degression or disappearance;
10 Reverse power
3.0.2 The exit action of protection device may be classified into the following manners:
1 Halt: Disconnect the breaker of the power generator (or generator transformer), and suppress the excitation: close up main throttle valve for steam turbine generator; and close up water diversion leaf for hydraulic generator;
2 Parallel off excitation suppression: Disconnect the breaker of power generator (or generator transformer), suppress excitation, reject load of steam (water) turbine;
3 Parallel off: Disconnect breaker of power generator (or generator transformer).
4 Narrow down the fault incidence;
5 Signal: Give out audible and visible alarm;
3.0.3 For the phase fault of generator stator winding and outgoing line, corresponding protection device shall be installed to be used as the main protection of the power generator. The protection device shall be acted until the halt, and shall be in accordance with the following requirements:
1 For the 1MW or below power generator that operates independently: If outgoing line lies in the neutral point side, overcurrent protection shall be installed in the neutral point side; if no outgoing line is found in the neutral point side, low-voltage protection shall be installed in the generator end.
2 1MW or below and other power generator or power generators parallel running with the power system shall be installed with current quick-break protection in the generator end. When the sensitivity of the current quick-break protection fails to meet the requirement, longitudinal differential protection may be installed; as for the power generator without outgoing line in the neutral point side, low voltage blocking and overflowing protection may be installed.
3 For power generator of 1MW or above, longitudinal differential protection shall be installed. For the generator transformer group, when breaker exists between the power generator and the transformer, the power generator and transformer shall be installed with longitudinal differential protection independently; when no breaker exists between the power generator and transformer, longitudinal differential protection sharing for the generator transformer group may be installed.
GB/T 50062-2008 The following standards are cited：
