The Gas-fired power plant unit is generally composed of engine, generator, unit integrated control system, oil circuit system and power distribution system. The differences in parameters and performance between high-voltage generator sets and low-voltage generator sets are mainly reflected in the generator part and distribution system part. The power part of the generator set in the communication system - the engine or gas turbine engine - is basically the same for high-pressure and low-pressure units; The configuration and fuel volume of the oil system are mainly related to power, so there is no significant difference between high and low pressure units, so there is no difference in the requirements for the air intake and exhaust systems of the units that provide cooling.
High voltage generator sets generally require the installation of current quick break protection, overload protection, grounding protection, etc. When the sensitivity of current quick break protection does not meet the requirements, longitudinal differential protection can be installed. When a grounding fault occurs in the operation of a high-voltage generator set, it poses a significant safety hazard to personnel and equipment, so it is necessary to set up grounding fault protection.
The neutral point of the generator is grounded through a resistor. When a single-phase grounding fault occurs, the fault current flowing through the neutral point can be detected, and tripping or shutdown protection can be achieved through relay protection. The neutral point of the generator is grounded through a resistor, which can limit the fault current within the allowable damage curve of the generator, and the generator can operate with faults. Through grounding resistance, grounding faults can be effectively detected and relay protection actions can be driven. Compared to low-voltage units, high-voltage generator sets require the addition of neutral point distribution equipment such as resistance cabinets and contactor cabinets.
If necessary, differential protection should be installed for gas turbine generator sets. Provide three-phase current differential protection on the stator winding of the generator. When any two phases are short circuited or grounded, the fault current can be detected in both transformers, thereby driving the protection. By installing current transformers at the two outgoing terminals of each coil in the generator, the current difference between the incoming and outgoing terminals of the coil is measured to determine the insulation condition of the coil.