Magnetic Flux Density Feature Analysis and CT Saturation Region Recognition and Reconstruction Technology

doi:10.11930/j.issn.1004-9649.202302075

Abstract

Abstract:

To solve the problem of relay protection caused by CT saturation, a CT saturation identification method is proposed based on flux density characteristics and secondary current reconstruction technology in the distortion area. The CT saturation is identified based on the characteristics of the magnetic flux density trapezoidal region at saturation. Then the saturation region of CT is obtained using the slope of the flux variance to construct the saturation criterion based on the difference between entry saturation and exit saturation and calculate the time corresponding to the start and end point of secondary current saturation. The protection starting criterion is constructed based on the current at the maximum grid load to avoid protection misoperation. Finally, the least square method is used to reconstruct the secondary current in the saturation region to reflect the primary current reliably. The simulation results based on PSCAD/EMTDC software show that the proposed method is accurate and reliable, and can quickly and effectively identify the saturated CT segment with a time error of less than 1 ms.

Key words: CT saturation, magnetic flux density, saturation compensation, current reconstruction, least square method

CLC Number:

TM77

Feng WANG, Jia ZHU, Shaolin JIAO, Yiquan LI, Hua XIE, Qingchun ZHAO. Magnetic Flux Density Feature Analysis and CT Saturation Region Recognition and Reconstruction Technology[J]. Electric Power, 2023, 56(10): 179-185, 193.

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URL: https://www.electricpower.com.cn/EN/10.11930/j.issn.1004-9649.202302075

https://www.electricpower.com.cn/EN/Y2023/V56/I10/179

Figures/Tables 13

References 27

1	贾渭娟, 罗平. 供配电系统[M]. 重庆: 重庆大学出版社, 2016.
2	梁仕斌, 文华, 曹敏, 等. 铁心剩磁对电流互感器性能的影响[J]. 继电器, 2007, 35 (22): 27- 32.
	LIANG Shibin, WEN Hua, CAO Min, et al. The effects of remanent in CT core[J]. Relay, 2007, 35 (22): 27- 32.
3	陈武恝, 朱永海. 基于PSCAD的电流互感器饱和特性分析[J]. 大功率变流技术, 2009, (1): 39- 42. DOI
	CHEN Wujia, ZHU Yonghai. Analysis of current transformer saturation characteristics based on PSCAD[J]. High Power Converter Technology, 2009, (1): 39- 42. DOI
4	罗慧, 周卿松, 苗洪雷, 等. 基于LMD母线差动保护CT饱和检测方法研究[J]. 电力系统保护与控制, 2015, 43 (12): 49- 54. DOI
	LUO Hui, ZHOU Qingsong, MIAO Honglei, et al. A method for CT saturation detection based on LMD in busbar differential protection[J]. Power System Protection and Control, 2015, 43 (12): 49- 54. DOI
5	公茂法, 夏文华, 张晓明, 等. 基于HHT的抗CT饱和变压器故障识别新方法[J]. 电力系统保护与控制, 2013, 41 (22): 64- 70. DOI
	GONG Maofa, XIA Wenhua, ZHANG Xiaoming, et al. New method to identify transformer fault with anti-CT saturation based on HHT[J]. Power System Protection and Control, 2013, 41 (22): 64- 70. DOI
6	郑涛, 陈佩璐, 刘连光, 等. 计及直流偏磁的电流互感器传变特性对差动保护的影响[J]. 电力系统自动化, 2012, 36 (20): 89- 93.
	ZHENG Tao, CHEN Peilu, LIU Lianguang, et al. Transferring characteristics of current transformer affected by DC magnetic bias and its impact on differential protection[J]. Automation of Electric Power Systems, 2012, 36 (20): 89- 93.
7	翁汉琍, 王胜, 林湘宁, 等. 基于波形相似度的抗电流互感器饱和变压器相位差动保护[J]. 电力系统自动化, 2019, 43 (4): 132- 138.
	WENG Hanli, WANG Sheng, LIN Xiangning, et al. Waveform similarity based transformer phase differential protection against current transformer saturation[J]. Automation of Electric Power Systems, 2019, 43 (4): 132- 138.
8	SOLAK K, REBIZANT W, KLIMEK A. Fuzzy adaptive transmission-line differential relay immune to CT saturation[J]. IEEE Transactions on Power Delivery, 2012, 27 (2): 766- 772. DOI
9	朱佳杰, 邰能灵. 一种发电机差动保护的新方案[J]. 电工技术学报, 2008, 23 (3): 131- 136. DOI
	ZHU Jiajie, TAI Nengling. A novel scheme of generator differential protection[J]. Transactions of China Electrotechnical Society, 2008, 23 (3): 131- 136. DOI
10	朱国防, 陆于平. 扇环型制动区差动保护算法[J]. 电工技术学报, 2009, 24 (11): 172- 177.
	ZHU Guofang, LU Yuping. A novel differential protection with sector-ring restraint region[J]. Transactions of China Electrotechnical Society, 2009, 24 (11): 172- 177.
11	李振华, 兰芳, 钟悦, 等. 基于双骨架共绕技术的测量保护一体化电流传感器[J]. 高电压技术, 2022, 48 (11): 4427- 4436.
	LI Zhenhua, LAN Fang, ZHONG Yue, et al. Measurement-protection-integrated current sensor based on double-bobbin co-winding technology[J]. High Voltage Engineering, 2022, 48 (11): 4427- 4436.
12	林湘宁, 刘沛, 高艳. 基于数学形态学的电流互感器饱和识别判据[J]. 中国电机工程学报, 2005, 25 (5): 44- 48.
	LIN Xiangning, LIU Pei, GAO Yan. A novel method to identify the saturation of the current transformer using mathematical morphology[J]. Proceedings of the CSEE, 2005, 25 (5): 44- 48.
13	郑涛, 谷君, 黄少锋, 等. 基于数学形态梯度的变压器转换性故障识别新判据[J]. 中国电机工程学报, 2008, 28 (22): 75- 80.
	ZHENG Tao, GU Jun, HUANG Shaofeng, et al. A new algorithm to distinguish the transferring fault of transformer protection based on morphological gradient[J]. Proceedings of the CSEE, 2008, 28 (22): 75- 80.
14	杨恢宏, 谢百煌, 毕大强, 等. 基于虚拟制动电流采样点差动的CT饱和识别方法[J]. 继电器, 2006, 34 (13): 50- 53.
	YANG Huihong, XIE Baihuang, BI Daqiang, et al. Using the sampling differential protection based on the constructed restraint current to identify CT saturation[J]. Relay, 2006, 34 (13): 50- 53.
15	刘益青, 高伟聪, 王成友, 等. 基于差电流半周积分特征的电流互感器饱和识别方法[J]. 电网技术, 2016, 40 (9): 2889- 2895. DOI
	LIU Yiqing, GAO Weicong, WANG Chengyou, et al. Detection method for current transformer saturation based on characteristic of differential current by half-cycle integral algorithm[J]. Power System Technology, 2016, 40 (9): 2889- 2895. DOI
16	刘益青, 武凯, 徐明阳, 等. 基于CT饱和准确识别的零序方向元件改进方案[J]. 电网技术, 2021, 45 (10): 4161- 4171.
	LIU Yiqing, WU Kai, XU Mingyang, et al. Improved scheme of zero-sequence direction element based on accurate recognition of CT saturation[J]. Power System Technology, 2021, 45 (10): 4161- 4171.
17	刘鹏辉, 焦兵豪, 郭向伟. 考虑CT饱和干扰的电力变压器励磁涌流识别方法[J]. 电网技术, 2022, 46 (9): 3633- 3641. DOI
	LIU Penghui, JIAO Binghao, GUO Xiangwei. Magnetizing inrush identification method of power transformer considering CT saturation interference[J]. Power System Technology, 2022, 46 (9): 3633- 3641. DOI
18	牛火平. 基于二次谐波电流含有率识别CT饱和方案[J]. 云南电力技术, 2017, 45 (3): 25- 26, 31. DOI
	NIU Huoping. A new approach of discriminating CT saturation based on percentage of second harmonic current[J]. Yunnan Electric Power, 2017, 45 (3): 25- 26, 31. DOI
19	BEHI D, ALLAHBAKHSHI M, BAGHERI A, et al. A new statistical-based algorithm for CT saturation detection utilizing residual-based similarity index[C]//2017 Iranian Conference on Electrical Engineering (ICEE). Tehran, Iran. IEEE, 2017: 1072–1077.
20	ETUMI A A, ANAYI F. The application of correlation technique in detecting internal and external faults in three-phase transformer and saturation of current transformer[J]. IEEE Transactions on Power Delivery, 2016, 31 (5): 2131- 2139. DOI
21	李江峡, 黄景光, 张宇鹏, 等. 抑制直流偏磁导致的互感器饱和的直流补偿法[J]. 科学技术与工程, 2021, 21 (9): 3618- 3625. DOI
	LI Jiangxia, HUANG Jingguang, ZHANG Yupeng, et al. Direct current compensation of the current transformer transient saturation caused by direct current bias suppression[J]. Science Technology and Engineering, 2021, 21 (9): 3618- 3625. DOI
22	ZHENG T, HUANG T, MA Y L, et al. Histogram-based method to avoid maloperation of transformer differential protection due to current-transformer saturation under external faults[J]. IEEE Transactions on Power Delivery, 2018, 33 (2): 610- 619. DOI
23	PAN J P, VU K, HU Y. An efficient compensation algorithm for current transformer saturation effects[J]. IEEE Transactions on Power Delivery, 2004, 19 (4): 1623- 1628. DOI
24	张旭, 徐永海, 刘子腾, 等. 考虑系统侧谐波电压波动的光伏接入点谐波发射水平评估方法[J]. 中国电力, 2021, 54 (3): 109- 116.
	ZHANG Xu, XU Yonghai, LIU Ziteng, et al. A method for assessing harmonic emission level of photovoltaic access point considering system-side harmonic voltage fluctuations[J]. Electric Power, 2021, 54 (3): 109- 116.
25	黄潇潇, 杨韬, 郑骁麟, 等. 基于PMU量测信息的短线路同杆并架双回线参数辨识[J]. 中国电力, 2020, 53 (7): 141- 148.
	HUANG Xiaoxiao, YANG Tao, ZHENG Xiaolin, et al. Parameter identification of short parallel double-circuit lines based on PMU measurements[J]. Electric Power, 2020, 53 (7): 141- 148.
26	林国营, 宋强, 潘峰, 等. 基于差分平面法的CT饱和检测及补偿研究[J]. 电测与仪表, 2018, 55 (17): 146- 152. DOI
	LIN Guoying, SONG Qiang, PAN Feng, et al. Research of CT saturation detection and compensation based on differential plane method[J]. Electrical Measurement & Instrumentation, 2018, 55 (17): 146- 152. DOI
27	柳焕章, 王兴国, 周泽昕, 等. 一种利用电流突变量采样值的电流互感器饱和识别方法[J]. 电网技术, 2016, 40 (11): 3574- 3579. DOI
	LIU Huanzhang, WANG Xingguo, ZHOU Zexin, et al. A CT saturation identification method using sampled current fault component data[J]. Power System Technology, 2016, 40 (11): 3574- 3579. DOI

饱和次数	饱和开始时间/s		误差/s	饱和结束时间/s		误差/s
饱和次数	实际	检测	误差/s	实际	检测	误差/s
1	1.004	1.005	–0.001	1.013	1.013	0
2	1.018	1.018	0	1.022	1.021	0.001
3	1.025	1.026	–0.001	1.033	1.033	0
4	1.038	1.038	0	1.041	1.041	0

饱和次数	饱和开始时间/s		误差/s	饱和结束时间/s		误差/s
饱和次数	实际	检测	误差/s	实际	检测	误差/s
1	1.004	1.005	–0.001	1.013	1.013	0
2	1.018	1.018	0	1.022	1.021	0.001
3	1.025	1.026	–0.001	1.033	1.033	0
4	1.038	1.038	0	1.041	1.041	0

饱和次数	饱和开始时间/s		误差/s	饱和结束时间/s		误差/s
饱和次数	实际	检测	误差/s	实际	检测	误差/s
1	1.010	1.009	–0.001	1.015	1.015	0
2	1.025	1.026	–0.001	1.035	1.034	0.001

饱和次数	饱和开始时间/s		误差/s	饱和结束时间/s		误差/s
饱和次数	实际	检测	误差/s	实际	检测	误差/s
1	1.010	1.009	–0.001	1.015	1.015	0
2	1.025	1.026	–0.001	1.035	1.034	0.001

饱和次数	饱和开始时间/s		误差/s	饱和结束时间/s		误差/s
饱和次数	实际	检测	误差/s	实际	检测	误差/s
1	1.004	1.005	–0.001	1.013	1.013	0
2	1.018	1.018	0	1.022	1.021	0.001
3	1.025	1.026	–0.001	1.033	1.033	0
4	1.038	1.038	0	1.041	1.041	0