产品规格：
产品数量：
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关 键 词：专业生产发电机保护测控装置定制
行 业：电气 电气成套设备 变电站
发布时间：2020-11-25
1.3 function configurationFunction configuration of SAI3880D digital generator differential protection deviceDifferential quick break, ratio brake differential, CT disconnection locking differential, CT disconnection alarm, stator overvoltage protection, stator ground fault protection, overload alarm, anti time overcurrent protectionFunction configuration of backup protection device for SAI3881D digital generatorTransverse differential protection, loss of excitation protection, rotor one point grounding protection, rotor two points grounding protection composite voltage over current protection, inverse time negative sequence overcurrent protection, Pt disconnection alarm, non electricity protection (generator water shutoff, and the generator thermal, generator excitation accident, main steam valve closed),
The rotor low voltage action criterion equation is：
Kf×Vfd/125 < (P-Pt)/866
3.5 Over load protection
Generator stator winding protective reaction of load generator stator winding overload or fault caused by overcurrent caused overheating winding, discrimination protection generator winding B phase current size, when the current is higher than setting value when the delay send alarm signal.
3.6 compound voltage over current protection
Generator compound voltage over-current protection is as a generator of symmetric and asymmetric short-circuit fault back-up protection, protection discriminant generator three-phase current, AC phase voltage and negative sequence voltage, when any phase current is greater than the fixed value, and AC phase voltage less than fixed value or negative sequence voltage is greater than the fixed value export protection settings have two period of time delay, a movement in solution column or splitting demagnetization, off action to stop, protection can choose to take the current memory function.
3.7 inverse time overcurrent protection
Generator anti time limit over current protection of the generator stator winding current size, the protection of the winding due to the current too large and lead to the stator winding overheating, the protection of the three-phase current size of the judge, from three parts:
1)under the time limit: when the three-phase current is greater than the lower limit of the value of any phase, but not meet the anti time limit start value, press the lower limit delay action on the alarm signal;
2) inverse time: when the three-phase current any phase current is larger than the inverse time starting value, according to the inverse time lag action equation I2-1 t is greater than or equal to K acts, type: I for the generator current standard? Value, K - generator stator winding allows thermal time constant.
3) the upper bound limit: when the three-phase current is greater than the upper limit value, the time limit is delayed by the time limit.
3.8 transverse differential protection
Generator transverse differential protection is usually used for the reaction of generator stator winding inter turn short circuit and a parallel windings open welding, protection from the generator neutral point between two branch imbalance fundamental current, but current is greater than fixed value setting delay action on the alarm or trip.
3.9 inverse time negative sequence overcurrent protectionPower system occur asymmetric short-circuit and three-phase load imbalance may be the negative sequence current flowing in the stator winding of the generator, and produce harmonic current in the rotor, rotor surface overheating caused, generator's inverse time negative sequence over the protection of rotor flow under the situation not long overheated rotor insulation degradation caused damage to the generator, discrimination protection of generator stator negative sequence current size, consists of three parts:
1) under the time limit: when the negative sequence current is greater than the lower bound value but does not meet the start value of the anti time limit, the alarm signal is delayed by the lower limit;
2) inverse time: when the negative sequence current is larger than the inverse time start value, according to the inverse time lag action equation I22-K t is equal to or larger than a action, type: I2-- generator negative sequence current standard? Value, K - generator operation value of negative sequence current in the standard, a generator rotor surface bear negative sequence current capability of constant;
3) the upper bound limit: when the negative sequence current is greater than the upper bound limit, the upper limit is delayed by the time delay.
