Study On Synchronous Closing Technology Of Circuit Breaker

In order to meet the requirements of balance between supply and demand changing in power grid, electrical equipments should be put on or cut off in some parts of the power grid. But these operations may leading to transient response and spread in the system, not only destroy the circuit breakers themselves and the other equipments, but also cause relay protection devices miss-operation, or even endanger the power system stability, which get more and more attentions in the background of the power quality requirements increasingly stringent.Synchronous closing technology is an intelligent control technology that the dynamic and static contacts of circuit breaker closing at the specified phase angle of the system voltage waveform under the control of the control system, in order to make no-load transformers, capacitors and load lines switch on the power system when impacts to electrical equipments and system are the minimum. The circuit breaker with synchronous closing technology can effectively reduce the inrush current and over-voltage when closing from the principle. The technology is better than closing resistor, series reactor and other traditional methods. But the actual accuracy and reliability of movement has been a bone of contention. Therefore, this article did some researches about synchronous closing technology of high voltage circuit breaker.First, This paper did some research about the closing time prediction algorithm which is the core algorithm of synchronous closing technology of high-voltage circuit breaker. Duo to the factors of pre-arcing characteristics, ambient temperature, control voltage and so on affect closing time, therefore, base on the established data of relation between closing time and effect factors of a 10 kV permanent magnet vacuum circuit breaker and a 145kV SF6 spring circuit breaker, and using the neural network and the genetic algorithm toolbox in MATLAB software, this paper studied a genetic optimizing BP neural network algorithms to forecast closing time.Second, the inrush current is the reason that the filters on back to back converter station was damaged. Therefore, using electromagnetic transient simulation(ATP/EMTP) software, this paper analyzed the effect to limiting closing inrush current when circuit breaker with synchronous technology of the filters. Base on the inrush limit standard, this paper researched the error requirements of predicting closing time. And analyzed capacitor closing over-voltage.Finally, based on the previous chapter, this paper calculated the breakdown voltages of a 252kV circuit breaker by ANSYS software. Combining the different breakdown voltages at gap distances of circuit breaker with the closing travel curve under the rated condition, the relation curve between breakdown voltage and time was obtained. And comparing the system voltage at both ends of the contacts, closing deviation and closing objective point and the over-voltage value was obtained.Through above researches, this paper provided some theories about synchronous closing technology of high voltage circuit breaker.