负序相量快速算法的设计及应用

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摘要：灵敏性、可靠性、选择性及快速性是电力系统继电保护技术所需要具备的四个要件。继电保护的选择性是指继电保护装置能够有选择性的切除故障系统，这样可将停电范围降低到最小，最好的结果是可以做到不中断对用户的供电。故障发生时尽快地切除故障源可以极大改善电力系统稳定性，最大可能地减少故障设备的损坏程度，同时也最大可能地缩短电力用户在电能质量下降状态下用电的时间。因此，当电力系统发生不正常运行状态或者某些电力设备和元件出现故障时，对电力系统继电保护装置的要求是希望它能尽可能快速的启动，以便故障源能被迅速隔离或清除切除，这也称之为高速保护，方向保护在高速保护领域扮演了一个重要的角色。43267

基于负序电压、电流相位关系的负序方向元件在强电源侧远端故障或高阻故障等情况下保护安装处的负序电压、电流幅值较小，而导致两者的相差计算结果误差过大，从而使保护误动或拒动。另外，传统方法采用全波傅里叶算法来计算系统故障状态下的基波负序相量，保护算法动作时间在一个基波周期以上。于是提出了基于负序电抗的方向元件,该方向元件灵敏度高,不需要设置电流、电压门槛值,即使保护安装处负序电压、电流的幅值较小,仍可以准确地判别方向。但是传统的工频突变量方向元件在实际运行过程中存在大系统负序故障时保护灵敏度不足的隐患，针对这一不足，在本文的研究中，基于变形帕克变换，提出了基波负序相量快速算法，可在短时间内算出保护安装处负序相量。该快速相量计算方法及保护原理本质上属于暂态方法，动作速度可与暂态保护相比拟，但保护的可靠性有了很大的提高:751!文~论`文/网www.751com.cn。

在进行理论分析之后，又对该方法进行了大量的仿真实验，从结果我们可以看出：所提出的快速算法能够快速、可靠地判断各类不对称故障方向，其性能不受故障电阻、系统参数等的影响，具有良好的工程应用前景。

毕业论文关键词：可靠性；方向元件；变形帕克变换；高速；负序方向保护；故障分量网络

A Novel High Speed Directional Relay Algorithm Based On The Negative Sequence Reactance

ABSTRACT:Sensitivity、reliability、selectivity and rapidity are four important conditions of power system relay protection technology. The selective action of relay protection can limits the power fault range cut to the minimum, and even be done without interruption of the user's power supply. It can greatly improves the stability of the power system as soon as possible to remove the fault source , and try the best to reduce the damage to the equipment, at the same time, it is also possible to shorten the time of power users to use power in the state of decline of power quality. As a result, when the power system is not functioning properly or some power equipment and components malfunction, the requirement of the power system relay protection device is that it can be started as fast as possible, in order to that the fault source can be quickly isolated or removed, It is also called high speed protection, directional protection plays an important role in the field of high speed protection.

In the case of a strong power supply side remote fault or high resistance fault, because of the negative sequence directional element based on negative sequence voltage and current phase relation, the negative sequence voltage and current amplitude of the protective installation are small, which makes the error of the calculation result is too large between them, at the same time, it also makes the protection malfunction or refuse to move.In addition, the full wave Fourier algorithm is used to calculate the fundamental frequency negative sequence, The action time of the protection algorithm is above a fundamental period. So the direction element based on negative sequence reactance is proposed, The directional element has high sensitivity, no need to set the current and the voltage threshold value, even if the negative sequence voltage and current amplitude of the protection installation is small, the direction can be accurately distinguished. But the traditional power frequency variable of directional element has a hidden danger of insufficient protection sensitivity of large system forward fault In the actual operation process, To solve this problem, A fast algorithm for the fundamental negative phase sequence based on Parke transform is proposed in this paper, which can calculate the negative phase sequence in a short time. The calculation method and protection principle of the fast phase is essentially a transient method, and the action speed can be compared with the transient protection, but the reliability of the protection is greatly improved.