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What protection should the generator install? What are their roles?

          Generator protection and other sets of load protection is somewhat different, because the generator excitation current and excitation voltage and the current switchgear current and voltage are also very different, so we have a very large gap in the protection of installation, in order to protect The entire generating units and even the entire power plant safe and reliable operation, we will talk in detail about the generator may occur failures and abnormal working conditions, should be based on the capacity of the generator is selectively installed the following protection.

          1, Longitudinal differential protection: for the stator windings and the phase-to-phase short-circuit protection.

          2, cross-connected differential protection: phase winding inter-turn short circuit protection. This type of protection is only provided when two or more parallel branches of one phase stator windings form two or three neutral lead terminals.

          3, single-phase ground protection: single-phase ground for the generator stator winding protection.

          4, excitation loop ground protection: excitation circuit ground fault protection.

          5, low excitation, loss of magnetic protection : In order to prevent large generators low excitation (excitation current below the quiescent limit of the corresponding excitation current) or loss of excitation (excitation current is zero), absorb a large amount of reactive power from the system System adversely affected, generators of 100 MW and above are equipped with this protection.

          6, Overload protection: Generator over the rated load operation for a long time signal protection. Small and medium-sized generators installed only stator overload protection; large generators should be installed stator overload and excitation winding overload protection.

          7, the stator winding over-current protection: When generator short-circuit protection outside the scope of short-circuit protection, and short-circuit protection or circuit breaker refuse action, this protection as an external short-circuit backup, but also double differential protection back-up protection.

          8, the stator winding over-voltage protection: used to prevent sudden rejection of all the load caused by stator winding over-voltage, hydro-generator and large turbo generator installed overvoltage protection, small and medium-sized turbine generator is usually not installed Over voltage protection.

          9, negative sequence current protection: asymmetrical short circuit or power system asymmetrical three-phase load (such as electric locomotive, electric arc furnace and other single-phase load is too large), will make the rotor end, the inner surface of the retaining ring current density A large part of the overheating, causing the rotor burns, it should be installed negative sequence current protection.

          10, out of step protection: the reaction of large generators and system oscillation process out of step protection.

          11, reverse power protection: When the steam turbine main steam door is mistakenly closed, or furnace protection action to close the main steam valve and the generator outlet circuit breaker is not tripped, the active power is absorbed from the power system to cause the turbine accident, so large units to be installed Reverse power protection with reverse power relay for turbine protection

          For these circumstances, we can choose according to their own needs 988 generator backup protection monitoring and control devices, 998 generator differential protection and control devices , 989 generator grounding protection and monitoring devices, 988C generator integrated protection and monitoring devices to meet Various types of generator protection needs. My company generator protection product line to meet the capacity of various turbines, turbines, diesel generating sets of protection and measurement and control, welcomed the industry friends came to discuss cooperation!

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