Research On Coordinated Control System Optimization For Unit Plant Based On Grid Frequency Regulation Demand

The power system is an organic whole composed of power generation side,power transmission measurement,power distribution side and power side.In order to ensure the safe and economical operation of the power system and achieve the energy balance between the power generation load and the load on the power supply side,the power grid needs to adjust the system frequency in real time,which sets higher requirements for the coordinated control system of the plant unit.In order to meet the requirement of frequency adjustment of power system,this paper takes a typical subcritical 300 MW unit as the research object,and studies the optimized method of coordinated control system from the aspects of rapidity and economy.In terms of rapidity,it takes two optimization schemes.The first is heat storage compensation of turbine program based on condensate throttling,the specific process is as follows:At first,we should detect the thermal parameters in various typical load conditions,then calculate the capacity of condensate throttling which includes available condensation water flow and adjustable load and adjustment time.then an optimal control system based on condensate throttling is designed to improve the heat storage compensation of turbine.The second is heat storage compensation of boiler program based on boiler intelligent feedforward,boiler intelligent feedforward mainly includes static feedforward and dynamic feedforward.For this 300 MW unit,several static feedforward channels have been added.At the same time,a three-stage dynamic feedforward curve has been designed.According to theoretical analysis and site debugging,the specific parameters of each curve are determined to increase the heat storage of boiler and change load rapidly.In terms of economy,this paper calculates the boiler efficiency and coal consumption under the same load and different pressures,the higher the boiler efficiency and the lower the coal consumption,the better the economy of the unit.In this way,the original sliding pressure running curve of the unit is optimized.In addition,this article also adds the circuit of pressure pull-back in the original coordination control system circuit.When the load command is increased by a large margin,the main steam valve on the steam turbine may open excessively quickly,causing the pressure in the turbine to drop too fast and resulting in drastic fluctuation of the drum water level.The purpose of setting the circuit of pressure pull-back is to prevent the above situation and to control the speed of the pressure change so as to keep the working condition stable when the load changes.