The following protection should be installed selectively according to the capacity of the generator for possible faults and abnormal working conditions of the generator.
(1) Longitudinal differential protection: phase-to-phase short-circuit protection of stator winding and its lead wire.
(2) Cross-connected differential protection: protection of one-phase inter-turn short circuit of stator winding. This PROTECTION IS PROVIDED ONLY WHEN THE ONE-PHASE STATOR WINDING HAS TWO OR MORE PARALLEL branches FORMING TWO or THREE NEUTRAL LEADS.
(3) Single-phase grounding protection: single-phase grounding protection for generator stator windings.
(4) Excitation circuit grounding protection: ground fault protection for excitation circuit.
(5) Low excitation, loss of excitation protection: in order to prevent large generator low excitation (excitation current below the static stability limit corresponding to the excitation current) or loss of excitation (excitation current is zero), from the system to absorb a large amount of reactive power and have adverse effects on the system,100MW and above capacity generators are equipped with this protection.
(6) Over load protection: the protection of the generator acting on the signal when the generator is operating for a long time beyond the rated load. Small and medium-sized generators are only equipped with stator overload protection; Large generators should be equipped with stator overload and excitation winding overload protection respectively.
(7) stator winding overcurrent protection: when short-circuit occurs outside the vertical difference protection range of the generator, and the short-circuit element protection or circuit breaker refuses to act, this protection as an external short-circuit backup, but also as a vertical difference protection backup protection.
(8) stator winding overvoltage protection: it is used to prevent the stator winding overvoltage caused by suddenly throwing off all the load. Water turbine generator and large turbine generator are equipped with overvoltage protection, small and medium-sized turbine generator is usually not equipped with overvoltage protection.
(9) negative sequence current protection: asymmetric short circuit or three-phase load asymmetry in the power system (such as electric locomotive, electric arc furnace and other single-phase load proportion is too large), will make the rotor end, inner surface of the ring and other current density parts of overheating, resulting in local burn of the rotor, so negative sequence current protection should be installed.
(10) Out-of-step protection: out-of-step protection that reflects the oscillation process of large generator set and system.
(11) Reverse power protection: when the main valve of the turbine is closed by mistake, or when the main valve of the generator is closed by the protection action of the engine and furnace and the outlet circuit breaker of the generator is not tripped, the active power is absorbed from the power system and the turbine accident is caused. Therefore, the reverse power protection composed of reverse power relay should be installed in large units to protect the turbine.
Jiangsu Meiao Power Technology Co., Ltd. is an important manufacturer of diesel generators. The company mainly manufactures and sells diesel generator sets with power of 3-3000kW, mobile power station of 24-600kW, Marine emergency diesel generator set of 24-800kW, gas generator set, heavy oil generator set and all kinds of imported series, special series (trailer, static speaker, mobile lighthouse, container, etc.) diesel generator At the same time, we are engaged in generator set maintenance and after-sale service of generator set accessories.
