|
| 摘要: |
| 分析了配电网单相接地时的故障特征,对现有基于稳态量与暂态量的故障选线方法进行分析比较,指出故障暂态电流幅值比稳态对地电容电流大得多,而且几乎不受消弧线圈影响,因此,利用暂态电流进行选线可以克服稳态选线方法灵敏度低、易受消弧线圈影响的缺点。为了精确提取故障时的暂态信号用于选线,发挥小波包能进行时频联合分析的优势,对发生接地故障时各线路的暂态零序电流进行小波包分解,提取出各频带信号分量的小波包系数。其中,电流采样值直接用于形成故障选线的第1判据,多个高频分量的小波包系数则形成综合判据以提高选线准确性。该方法能适应小电流接地系统中的不同故障模式,选线准确性高。仿真验证了该方法的有效性。 |
| 关键词: 小电流接地,故障选线,暂态量,小波理论,小波包 |
| DOI： |
| 分类号:TM76 |
| 基金项目: |
|
| Faulty feeder detection based on transient current and wavelet packet in distribution system |
|
BI Yan-qiu ZHAO Jian-guo
|
| Abstract: |
| Characteristics of single-phase-to-ground fault in distribution system are analyzed,and the faulty feeder detection methods based on steady and transient component are compared.Since the amplitude of transient current is much larger than that of steady-state line-to-ground capacitive current and not influenced by the Petersen-coil,using transient current to select faulty feeder may improve selection sensitivity and reduce vulnerability to Petersen-coil.As wavelet packet can carry out time-frequency combined analysis,the transient zero-sequence current of each feeder are decomposed with wavelet packet to extract the wavelet packet coefficients of different frequency components.The sampled current is directly used as the first criterion and the wavelet packet coefficients of multiple high-frequency components are used as the synthesized criterion to improve the accuracy of faulty feeder detection,which is more accurate and adaptive for various fault modes in small current grounding system.The simulation validates its effectiveness. |
| Key words: small current grounding,faulty feeder detection,transient component,wavelet theory,wavelet packet |
