The protection system of common gasoline

Author：gdlhwt Time：2014-09-13  

In order to maintain the normal working state of gasoline generator equipment, for the capacity of the equipment should be installed in some selective protection system.

(1), single phase grounding fault protection for stator winding: single-phase grounding protection.

(2), loss of excitation protection, low excitation: in order to prevent large equipment of low excited (excitation current excitation current is lower than the static stability limit of the corresponding) or loss of excitation (excitation current is zero), from the system to absorb a large amount of reactive power and adversely affect system capacity, 100MW and above are installed in the protection.

(3), over load protection: long time more than the protection of rated working load acting on signal. Small and medium-sized power equipment just pack setup sub overload protection; large unit shall be respectively arranged stator load and the excitation winding overload protection.

(4), negative sequence current protection: asymmetric short circuit or three-phase load power system (single phase load such as electric locomotives, electric arc furnace in proportion too large), will make the rotor end, retaining ring inner surface current density greatly parts of overheating, causing the rotor local burns, therefore, should be installed negative sequence current protection.

(5), longitudinal differential protection: phase short circuit protection of stator winding and the lead wire.

(6), reverse power protection: when the steam turbine main steam valve closing error, or furnace protection action to close the main stop valve and outlet circuit breaker fails to trip, absorb active power from the power system caused by steam turbine accident, so the large unit should be equipped with inverse power protection power relay form, used for protection of steam turbine.

(7), the stator winding current protection: when the longitudinal differential protection outside the scope of the short circuit occurs, and the short-circuit element protection or breaker refusing action, such as external short circuit protection backup, backup protection also doubles as a longitudinal differential protection.

(8), out of step protection: out of step protection for large generator and system oscillation reaction process.

(9), excitation loop grounding protection: for ground fault protection of the excitation circuit.

(10), transverse differential protection: as a phase stator winding interturn short circuit protection. Only when a stator winding with two or more parallel branch constitutes two or three neutral point lead out end, before installing this kind of protection.

(11), the stator windings overvoltage protection: to prevent the sudden load rejection to all caused by stator winding voltage of large steam turbine, hydraulic turbine and are installed in over voltage protection, small and medium-sized turbine usually do not install over voltage protection.

Typically, gasoline generators will be installed with the above eleven kinds of protection system, to protect the equipment from damage of external causes.