Method and control device for automatically reducing reactive power before decommissioning of large combined cycle units

Abstract

The invention relates to a large combined cycle set before-separation automatic idle work reducing method and a control device. The method is characterized in that a distributed control system (DCS) is used for detecting the working state of a set, and by controlling exciting currents through an excitation system of the set, the fact that large combined cycle set before-separation idle work is reduced to a target value automatically is achieved. The structure is characterized in that the DCS, a detecting loop and a generator excitation controller AVR are included, the detecting loop is provided with a halt signal detecting end, a generator power utilization end voltage detecting end, an active power detecting end and an idle work detecting end, an output end of the detecting loop is connected with an input end of the DCS, an output end of the DCS is connected with a control input end of the generator excitation controller AVR, and an output end of the generator excitation controller AVR is connected with an input end of the excitation system of the generator set. The large combined cycle set before-separation automatic idle work reducing method and the control device have the advantages that voltage fluctuation caused by the fact that work conditions are changed suddenly, voltages at the generator end can jump because of separation, and a power grid gets rid of a large amount of idle work suddenly can be avoided.

Description

Technical field: [0001] The invention relates to a method and a control device for automatically reducing reactive power before decommissioning of a large combined cycle unit. It belongs to the field of power generation technical equipment. Background technique: [0002] In the field of power generation technology, in order to reduce the impact on the power grid and the generator set, when the generator set is shut down normally, it is generally required to reduce the active power and reactive power to close to zero, so as to reduce the impact on the power grid and the generator set. At present, the design of large-scale gas-steam combined cycle unit control system is often based on the control of the gas turbine, ignoring the control of the reactive power of the motor. When decoupling, the generator often has a high reactive power load, which leads to a sudden change in power status at the moment of decoupling, and the terminal voltage of the generator will suddenly rise, ...

AI Technical Summary

Problems solved by technology

[0004] One of the purposes of the present invention is to provide a method for automatically reducing reactive power before decommissioning of large combined cycle units in order to solve the problems of sudden changes in power grid power status and violent voltage fluctuations when the current technology is shut down

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