Practice And Exploration Of Frequency Protection Setting Strategy For ASelf-provided Power Plant In ASugar Factor

The sugar industry is a pillar industry in Guangxi,accounting for about two-thirds of the country's production.Considering the production process and production costs,almost all sugar factories in the zone are equipped with self-supplied power plants.Because the sugar factory is in the raw material sugarcane production area and belongs to the end of the power grid,the power supply capacity and reliability are difficult to meet the requirements.The sugar factory provides stable high-pressure steam to generate electricity and boil sugar through coal-fired and bagasse mixed combustion,ensuring the sugar factory.Under the premise of providing reliable power for production operation,it can also realize optimal resource allocation and improve economic efficiency.Most of the self-supplied power plants are connected in parallel with the external power grid to form a parallel operation,and the energy exchange of the tie lines is used to ensure the power quality of the sugar factory.Because it is at the end of the power grid,the reliability of power supply is poor.When the power grid trips due to a fault,if the self-supplied power plant is not disengaged from the external power grid,it will have an islanding effect,supply power to the large load outside the plant,and finally drag and drop.Power plants cause incalculable losses.When the power is successfully disassembled,the frequency and voltage fluctuations will occur in the self-provided power plant.The output of the prime mover and the operating state of the excitation system must be adjusted in time according to the actual situation.When the output of the prime mover has reached full capacity,it is still necessary.Properly remove the load,ensure the operation of important loads,and ensure the normal operation of the sugar factory as much as possible.This paper takes the actual situation of the distribution and distribution system of a sugar factory as an example.By analyzing and comparing the existing common sampling algorithms,according to the constraints of hardware conditions,the sampling algorithm of power parameters such as voltage,current and frequency is selected;the calculation error is analyzed and determined to meet the requirements.Accurate sampling points,and the mathematical analysis method,the AC sampling algorithm is improved,eliminating the need for the general FFT butterfly operation requires address reverse order,greatly improving the operation rate;by analyzing and comparing the existing island detection method,clear The load limit conditions of the generator set of the self-provided power plant in the single-infinite mode are determined;the disassembly conditions and protection action logic of the external network failure are determined;and the'various loads of the sugar mill are classified according to the production process.The requirements were compiled for low frequency load shedding criteria.Finally,the LPC1768 processor based on ARM architecture and its system are used to realize the function of self-provided power plant frequency protection setting strategy.The device in this paper can realize the sensitive and reliable capture of faults and the disconnection of the external power grid in the case of the disappearance of the external power grid.At the same time,it realizes the function of three-wheel load reduction and protection latching,and also recognizes the malfunction caused by the short circuit of the power grid.Applicable to small and medium-sized enterprises equipped with self-supplied power plants,which can ensure the operation of the important load of the self-supplied power plant,reduce losses and improve economic benefits.