【作者】 许中；

【导师】 李新；

【作者基本信息】 重庆大学 ， 电气工程， 2010， 硕士

【摘要】 本文为分析10kV系统并联补偿电容器组合装置合闸时断路器故障的原因,对合闸的过渡过程进行深入的研究讨论,并采用电磁暂态仿真软件ATP-EMTP对过渡过程中过电压与过电流进行仿真计算与验证。本论文主要开展了以下工作:①求解单相RLC串联二阶电路正弦激励下的全响应,利用解析解分析二阶电路中的参数(R、L和C)、合闸初相角等对合闸过渡过程的影响。研究发现合闸初相角是过渡过程出现较大过电流和过电压的重要因素;电路中L的减小会使得过渡过程的电路电流显著增大而电容电压略有减小,会使过渡过程时间略小。并利用ATP-EMTP电磁暂态仿真软件对上述结论进行验证。②分析了并联补偿电容器组合装置中串联电抗间的耦合电感对合闸过渡过程的影响,建立了一个含耦合电感的三相二阶电路模型,通过对该电路进行等效解耦分析和ATP-EMTP仿真,得出了不同耦合情形的作用相当于使得回路等效电感值产生了不同的变化,从而因电感值的变化影响回路过渡过程的过电压和过电流,而且这个效应对电流的影响较为显著。③分析了三相断路器合闸的不同期对投运并联补偿组合装置的合闸过渡过程的影响。建立了分析该不同期合闸的三相电路模型,在复频域定量分析不同期合闸过程中较高过电压的诱发机制,并利用ATP-EMTP进行仿真验证,研究发现不同期使得中性点电压产生偏移振荡,并由之使得电容对地过电压增加;而且不同期时间间隔越长,中性点偏移越大。研究还发现由于合闸的不同期导致的实际合闸相角的变化使得过渡过程可能出现较大的过电流。④分析了真空断路器在合闸过程等效电阻对合闸过渡过程的影响。描述了合闸时断路器电阻的产生并对该电阻等效建模。并且在ATP中设计该等效电阻的仿真模型,建立ATP电路图进行仿真分析和定量计算,研究结果表明真空断路器的压缩行程的时间越长,阻尼作用越明显。综合研究上述研究得出:电路中存在的耦合电感、合闸的不同期等因素都可能会使过渡过程电容对地电压有所增大,但即使是极端情况也没有超过其绝缘配合值;而对过电流而言,变化较为灵敏,各因素均会使其有显著增大,而且持续时间较长。排除器件本身的因素外,断路器故障由过电流引起的可能较大。更多还原

【Abstract】 To find out the reasons of the explosion of breakers while putting parallel compensation capacitor into operation in 10kV power system, transition process of closing has been studied and discussed in depth in this article. ATP-EMTP is used for simulating the transition process and verifying the conclusions. The following work has been carried out.Reanalyzed the symmetrical three-phase circuit which be used to study the transition of breakers closing. With solving the whole solution of differential which describe second-order RLC series circuit response to sinusoidal excitation, this article studied the second-order circuit parameters (R, L and C) and the early closing phase angle how to impact the transition process. Found that the decrease of L would make the current significantly increased while the voltage is slightly reduced in the transition process, at the same time the transition time will be slightly smaller. The early closing phase angle is an important factor in causing the over-current and over-voltage. And then, ATP-EMTP is used to verify the above conclusion.A new circuit model containing Three-phase coupled inductors is established to analyze over-voltage and over-current in the transition of closing three-phase circuit breaker. Through decoupling and Laplace and inversely transforming the circuit, the influence of mutual inductance and different inductor polarities on the process of transition is discussed. In this paper, ATP-EMTP Power System Simulation Software is employed into calculating the over-voltage and over-current with the actual parameters, and the transition process under different situation of decoupling the circuit is contrasted.A new circuit model is established to analyze the over-voltage and over-current while breakers asynchronous closing. By selecting a set of practical operation 10kV system parameters and taking numerical solution to it, cause of the higher over-voltage and over-current in the transition of asynchronously closing is investigated. This paper simulated and analyzed the circuit with the ATP-EMTP simulation software and obtained a series of over-voltage and over current actual waveforms. The paper summarizes the law how breakers-closing interval and the value of capacitance and inductance impacted on the transition.Described the production of circuit breaker resistance, the equivalent model of resistance is established to study the role of which to the transition of closing. A new method to simulation the equivalent resistance designed in ATP-EMTP, simulated three phase circuit and got the conclusion that the longer the compression process, the more significant damping effect.In summary, the paper summarizes the following conclusions. Both coupled inductors and breakers asynchronous closing could increase the voltage, even in extreme cases did not exceed the insulation with the setting value. In terms of the over-current, the change is more sensitive. It appears much higher current, up to 6 times of the steady state. Therefore, Breaker failure is more likely caused by the over-current.更多还原