WO2015135264A1 - 电流互感器计量绕组的直流偏磁自动补偿装置 - Google Patents

电流互感器计量绕组的直流偏磁自动补偿装置 Download PDF

Info

Publication number
WO2015135264A1
WO2015135264A1 PCT/CN2014/079961 CN2014079961W WO2015135264A1 WO 2015135264 A1 WO2015135264 A1 WO 2015135264A1 CN 2014079961 W CN2014079961 W CN 2014079961W WO 2015135264 A1 WO2015135264 A1 WO 2015135264A1
Authority
WO
WIPO (PCT)
Prior art keywords
current
current transformer
winding
signal
compensation
Prior art date
Application number
PCT/CN2014/079961
Other languages
English (en)
French (fr)
Inventor
王忠东
万达
李红斌
黄奇峰
陈刚
陈铭明
卢树峰
杨世海
骆翻钿
李振华
朱晓龙
田正其
崔林
Original Assignee
国家电网公司
江苏省电力公司
江苏省电力公司电力科学研究院
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 国家电网公司, 江苏省电力公司, 江苏省电力公司电力科学研究院 filed Critical 国家电网公司
Publication of WO2015135264A1 publication Critical patent/WO2015135264A1/zh

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/18—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers
    • G01R15/183—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core
    • G01R15/185—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers using transformers with a magnetic core with compensation or feedback windings or interacting coils, e.g. 0-flux sensors

Definitions

  • the invention relates to a DC bias automatic compensation device for a current transformer metering winding, which has the function of automatically compensating for DC bias, and belongs to the field of electromagnetic measurement of power systems.
  • the current transformer has an important role in the substation to provide measurement signals for subsequent metering, protection and monitoring equipment.
  • the reliability and stability of its operation are very important.
  • Jinsute high-voltage DC operation in 2013, Jinsuo's 2013 Jinsut high-voltage DC asymmetric operation or single-maximum operation mode is mainly concentrated in the first month of January, the middle of Xiadian in February, and the middle and late May.
  • the longest single duration lasts for 5 days
  • the shortest lasts for 3 hours
  • the maximum DC access is 4000A.
  • the accumulated unipolar ground-to-ground operation time of the whole year was 267 hours
  • the accumulated asymmetric operation was 89 hours.
  • the DC bias caused by the single-pole operation of the DC transmission will cause the measurement error of the current transformer to be too large, and it will also cause hidden dangers to the safe and stable operation of the power grid.
  • the suppression of DC bias mainly adopts methods of current limiting, DC blocking, injection of reverse DC and potential compensation, namely: (1) neutral point series resistance; (2) neutral point series capacitance; (3) line series capacitance (4) Neutral point injection reverse DC current; (5) DC ground potential compensation method. All of the above methods use a simplified circuit model, ignoring the substation grounding network, soil structure, grid topology network, and the DC resistance of the substation transformer and the DC resistance of the transmission line and other related influencing factors, resulting in large errors.
  • the transmission line between substations is the main channel for DC current circulation.
  • the technical problem to be solved by the present invention is to eliminate or reduce the influence of DC bias on the current transformer on the secondary side of the current transformer.
  • the present invention adopts the following technical solutions.
  • the DC bias automatic compensation device for the current transformer metering winding is characterized in that: the metering iron core of the main body of the current transformer has a metering winding and a compensation winding, and the compensation winding is connected with a DC bias automatic compensation device.
  • the DC bias automatic compensation device for the current transformer metering winding is characterized in that:
  • the metering winding and the compensation winding are two independent coils of the same core, as shown in the figure K1K2 and coil K3K4, K2K3 are not connected), or different taps of one coil of the same core (such as K1K2K4, K2K3 connection).
  • the DC bias automatic compensation device for the current transformer metering winding is characterized in that: the DC bias magnetic automatic compensation device is installed on the current transformer base.
  • the DC bias automatic compensation device for the current transformer metering winding is characterized in that: the DC bias automatic compensation device comprises a standard converter, and the standard converter is connected in series to the secondary winding of the metering winding, and the current transformer is secondarily The side current signal is converted into a voltage signal;
  • the output signal of the standard converter is connected to the impedance conversion circuit, and the impedance conversion circuit has a high input impedance, so that the signal transmission path has an appropriate impedance matching;
  • the output signal of the impedance conversion circuit is converted into a frequency multiplied signal by the frequency multiplying circuit as a reference signal of the phase sensitive detection; the output signal of the impedance conversion circuit simultaneously passes through the band rejection filter circuit, and is used as an input signal of the phase sensitive detection;
  • the frequency multiplying circuit is used to generate a reference signal required by the phase sensitive detection circuit, and the band rejection filter circuit is used for filtering the power frequency signal to increase the signal to noise ratio;
  • the phase sensitive detection circuit is used for extracting the even harmonic signal of the secondary side output signal of the current transformer; the output signal of the phase sensitive detection circuit passes through the low pass filter circuit to filter out the high frequency component of the phase sensitive detection output signal to obtain a DC component. ;
  • the low-pass filtered output signal is calculated by the negative feedback controller and output after negative feedback adjustment.
  • the output of the voltage-controlled current source is proportional to the DC compensation current proportional to the primary DC current, so that the secondary output even harmonic is minimized.
  • the DC current is used as the compensation current of the secondary side compensation winding of the current transformer to achieve the best compensation effect.
  • the DC compensation energy can offset the DC component of the primary current and the DC bias of the current transformer. The effect of magnetism.
  • the negative feedback controller includes a subtractor and a PID controller.
  • the input signal and the set value are subtracted as the input of the PID regulator. After the PID is adjusted, the signal is output.
  • the invention designs a DC bias magnetic automatic compensation device for the current transformer metering winding, and the current transformer metering iron core has two independent windings of a metering winding and a compensation winding, and the metering winding works as a current transformer.
  • the output winding is used to inject the compensation current to offset the influence of the DC bias on the current transformer characteristic, thereby having the DC bias automatic compensation function.
  • the DC bias automatic compensation device is used for detecting the magnitude and phase of the even harmonic component of the output winding of the secondary side of the current transformer, thereby controlling the DC current source to inject a corresponding amount of reverse DC into the secondary winding compensation winding of the current transformer.
  • the current acts as a compensation current, and the compensation current generates a magnetic field in the compensation winding to cancel the magnetic field generated by the primary side direct current, thereby realizing automatic compensation of the current transformer DC bias.
  • FIG. 1 is a schematic view showing the overall structure of a DC bias magnetic compensation device for a current transformer metering winding of the present invention
  • FIG. 2 is a schematic view showing a mounting structure of a DC bias automatic compensation device for a metering winding of a current transformer according to the present invention
  • FIG. 3 is a schematic block diagram of a DC bias automatic compensation device for a current transformer metering winding
  • FIG. 4 is a test wiring diagram of a DC bias automatic compensation device for a current transformer metering winding
  • FIG. 5 is a DC bias of a current transformer metering winding Block diagram of the negative feedback controller of the magnetic automatic compensation device.
  • 11-busbar 12-current transformer, 13-normal metering winding output tap, 14-compensation winding tap, 15-DC biasing compensation device, 16-220V power plug, 17-second energizing coil.
  • the current transformer metering iron core has a metering winding and a compensation winding, wherein the metering winding and the compensation winding can be two independent coils of the same core, as shown in Fig. 1 coil K1K2 and coil K3K4, K2K3 are not connected It can also be a different tap of one coil of the same core, as shown in Figure 1 K1K2K4, K2K3.
  • the metering winding acts as an output winding for the current transformer to operate normally, while the compensation winding uses an unused winding of the multi-tap current transformer or a secondary winding designed to achieve compensation to inject the compensation current.
  • the DC bias automatic compensation function is realized by detecting the magnitude and phase of the even harmonic component of the secondary side output of the current transformer, and controlling the DC current source to inject a corresponding amount of reverse DC to the secondary winding compensation winding of the current transformer.
  • the current acts as a compensation current, and the compensation current generates a magnetic field in the compensation winding to cancel the magnetic field generated by the primary side DC, thereby realizing automatic online compensation of the current transformer DC bias.
  • the whole compensation process is closed-loop control. If the first compensation does not completely eliminate the influence of DC bias, the secondary output of the transformer still has the second harmonic component. By detecting the second harmonic component, the DC bias is continuously compensated. Until the second harmonic component is not included in the output.
  • the DC bias magnetic compensation technology first needs to detect the second harmonic content of the current transformer output, so as to quantitatively evaluate the primary side DC amount, thereby controlling the current source to generate a corresponding compensation DC to reduce or offset the primary side DC influence.
  • the difficulty of the DC bias magnetic compensation scheme is mainly to quantitatively obtain the second harmonic content, and automatically generate the compensation DC current according to the second harmonic content.
  • the current transformer DC bias automatic compensation device is designed, which adopts standard converter technology, impedance transformation technology, frequency doubling technology, band rejection filtering technology, phase sensitive detection technology based on multiplication principle, multi-stage filtering technology, Voltage controlled current source technology Surgery.
  • the standard signal converter is connected to the secondary winding of the metering winding, and the current signal of the secondary side of the current transformer is converted into a voltage signal for obtaining the secondary side current signal of the current transformer as the input of the DC bias automatic compensation device.
  • the converter mainly functions as a signal isolation and acquisition signal.
  • the designed standard signal converter is isolated by a small CT to ensure that the secondary side of the current transformer will not open, which is safe and reliable.
  • the secondary output current resistance R of the small CT is converted into a voltage signal and is input as a DC bias automatic compensation device.
  • the standard signal converter has a primary load of less than 0. 25 VA, and the load is small, and the distribution of the original secondary load of the current transformer is not substantially changed.
  • the output signal of the standard converter is connected to the impedance conversion circuit, and the impedance conversion circuit has a high input impedance, so that the signal transmission path has a more suitable impedance matching.
  • the impedance-converted signal is converted into a multi-frequency signal by a frequency multiplying circuit as a reference signal for phase-sensitive detection; on the other hand, after passing through the band-stop filter circuit, it is used as an input signal for phase-sensitive detection.
  • the frequency multiplying circuit is used to generate a reference signal required by the phase sensitive detection circuit, and the band rejection filter circuit is used for filtering the power frequency signal to increase the signal to noise ratio.
  • the input signal and the reference signal are used as input signals of the phase sensitive detection circuit, and the phase sensitive detection circuit is used for extracting the even harmonic signals of the secondary side output signal of the current transformer.
  • the output signal of the phase sensitive detection circuit passes through a low-pass filter circuit to filter out the high-frequency components of the phase-sensitive detection output signal to obtain a DC component.
  • the signal after low-pass filtering passes through the voltage-controlled current source circuit to generate a direct current proportional to the even harmonic content, which serves as the compensation current of the secondary side compensation winding of the current transformer to cancel the DC bias to the current transformer.
  • DC bias automatic compensation device power supply can be powered by an external power supply, or can be powered by a primary coil.
  • an external power supply is used for power supply, a power mode is required.
  • the block can ensure the normal power supply of the DC bias automatic compensation device.
  • the primary coil is energized, it is designed to start working at 3% of the rated primary current.
  • the measurement error caused by the DC bias to the transformer is relative to the transformer itself.
  • the DC bias magnetic compensation device stops working and DC bias compensation is not performed.
  • the designed DC bias automatic compensation device will not affect the normal operation of the current transformer under normal working conditions.
  • the following is an analysis of the effects of current transformer measurements under normal operating conditions.
  • the input signal of the device is taken from the secondary winding of the current transformer.
  • the DC current of the compensation winding K3K4 is not induced to the secondary winding K1K2; when the compensation winding and the metering winding For different taps of the same coil, the DC current of the compensation winding flows only through the circuit of the compensation winding K3K4 and does not flow through the secondary winding K1K2.
  • the compensation winding ⁇ 3 ⁇ 4 is connected to the voltage-controlled current source, and its impedance approaches infinity, so the compensation winding will not affect the secondary winding AC current. Therefore, the device does not adversely affect the current transformer metering itself during actual operation.
  • the designed DC bias automatic compensation device will not affect the normal operation of the current transformer in the event of failure of the device.
  • the following is an analysis of the effects of current transformer measurements on the failure of the device.
  • the magnitude of the DC bias current does not generally exceed a certain limit, and the output of the compensation device should not exceed this value.
  • the protection circuit part (Fig. l_b) is designed in the compensation device circuit. When the output current of the compensation device is too large, the protection circuit operates to make the device output 0, and no compensation is performed. 3) The power supply circuit of the compensation device is open or shorted
  • Figure 3 is a block diagram of the DC bias automatic compensation device for the current transformer metering winding, mainly including standard converter, impedance conversion circuit, frequency multiplier circuit, band rejection filter circuit, phase sensitive detection circuit, low pass filter circuit, voltage control Current source circuit, etc.
  • the standard converter is connected to the secondary winding of the metering winding, and the secondary current signal of the current transformer is converted into a voltage signal.
  • the output signal of the standard converter is connected to an impedance conversion circuit, and the impedance conversion circuit has a high input impedance, so that the signal transmission has a more suitable impedance matching.
  • the impedance-transformed signal is subjected to shaping and multiplication to ⁇ ⁇ as a reference signal for phase-sensitive detection; on the other hand, after 50 Hz band-stop filtering, it is used as an input signal for phase-sensitive detection.
  • the frequency multiplying circuit is used to generate a reference signal required by the phase sensitive detection circuit, and the band rejection filter circuit is used to filter the power frequency signal and increase the signal to noise ratio.
  • the input signal and the reference signal are used as input signals of the phase sensitive detection circuit, and the phase sensitive detection circuit is used to extract the even harmonic signals of the secondary side output signal of the current transformer.
  • the output signal of the phase sensitive detection circuit passes through a low-pass filter circuit to filter out the high-frequency components of the phase-sensitive detection output signal to obtain a DC component.
  • the signal after low-pass filtering passes through the voltage-controlled current source circuit, which is proportional to the even harmonic content.
  • the DC current is used as the compensation current of the secondary side compensation winding of the current transformer to offset the influence of the DC bias on the current transformer characteristics, thereby realizing the automatic compensation of the DC bias of the transformer and reducing the DC bias to the mutual inductance.
  • the influence of the measurement accuracy improves the measurement accuracy of the transformer.
  • Figure 4 is a test wiring diagram of the DC bias automatic compensation device for the current transformer metering winding.
  • the equipment used in the test includes: 1- regulator, 2-lifter, 3-DC current source, 4-capacitor cabinet, 5-standard current transformer, 6-calibrated current transformer, 7-standard signal conversion Box, 8-DC bias compensation device, 9-to-instrument calibrator.
  • the AC current source is composed of a voltage regulator 1 and a current booster 2, and the voltage regulator controls the output current of the current to be a large current; the DC current source 3 generates a direct current; the capacitor cabinet 4 is used to isolate the direct current so that the direct current does not flow through the alternating current.
  • the current booster while the DC current source has a high output impedance, so that the AC current flows through the DC current source, so the standard current transformer 5 will only pass the AC current, and the new current transformer 6 of this design will flow through the AC high current and The superimposed current of the direct current current, at this time, a DC bias automatic compensation device of the current transformer metering winding of the design will generate DC bias.
  • the current signal outputted by the metering winding of the current transformer is converted into a voltage signal by the standard signal conversion box 7 and then connected to the DC bias compensation device 8, and the output signal of the DC bias compensation device is fed back to the current transformer.
  • the compensation winding using the transformer calibrator 9 to verify the standard current transformer at the same time and the two current output signals of the new current transformer of the design, test the ratio difference and angular difference. The transformer accuracy after uncompensated and compensated lines is tested and compared.
  • the experiment without the compensation device shows that the automatic compensation device can detect the bias condition of the current transformer, and the DC current output has a certain proportional relationship with the DC current of the primary current.
  • the experiment after adding the compensation device shows that the automatic compensation device can obtain the even harmonic content quantitatively, It is enough to judge the bias of the transformer, and the output of the reverse DC current is automatically compensated, and the compensation effect is remarkable.
  • the experiment proves that the DC bias automatic compensation device of the current transformer metering winding of the design can realize the automatic compensation of DC bias magnetism, and the compensation effect is remarkable.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)

Abstract

一种电流互感器计量绕组的直流偏磁自动补偿装置，电流互感器的计量铁芯上具有计量绕组和补偿绕组两个独立绕组，所述补偿绕组与直流偏磁自动补偿装置连接。直流偏磁自动补偿装置用于检测电流互感器二次侧计量绕组输出信号中的偶次谐波分量的大小及相位，从而控制直流电流源向电流互感器二次侧补偿绕组注入相应量的反向直流电流作为补偿电流，补偿电流在补偿绕组中产生磁场，抵消一次侧直流所产生的磁场，从而实现对电流互感器直流偏磁的自动在线补偿。本装置对电流互感器直流偏磁的自动补偿效果显著。

Description

电流互感器计量绕组的直流偏磁自动补偿装置
技术领域
本发明涉及电流互感器计量绕组的一种直流偏磁自动补偿装置， 具有对直 流偏磁进行自动补偿的功能， 属于电力系统电磁测量领域。
背景技术
作为变电站一次设备的重要组成部分， 电流互感器在变电站中具有为后续 计量、 保护及监控设备提供测量信号的重要作用， 其运行的可靠性和稳定性非 常重要。
交、 直流混合运行的电网结构使得交、 直流系统之间的相互影响越加明 显， 双极高压直流输电线路检修或单极故障时需以单极 -大地回线方式运行 时， 会有很大的直流电流流过接地极， 此时会在大地上形成恒定的直流电流 场， 产生地表电位差， 在交流网络中变压器绕组、 架空线和大地形成的回路中 产生直流电流， 从而在变压器和电流互感器回路中产生直流偏磁。 直流偏磁会 加剧电流互感器的铁心饱和磁化， 引起电流互感器发生磁滞畸变， 改变电流互 感器的传变特性， 引起电流互感器的测量误差， 从而影响电流互感器的计量和 保护性能。
以 2013 年锦苏特高压直流运行工况统计看， 锦苏 2013 年锦苏特高压直流 不对称运行或单极大地运行方式主要集中在 1 月初末、 2 月中下甸、 5 月中下 旬、 6月初、 7月中甸、 9月中甸等期间， 最长单次持续时间 5天， 最短持续 3 小时， 入地直流最大达 4000A。 全年累计单极对地运行时间 267 小时， 累计不 对称运行 89 小时。 直流输电单极运行造成的直流偏磁会使电流互感器产生计 量误差偏大， 还会对电网安全稳定运行产生隐患。 目前， 抑制直流偏磁主要采取限流、 隔直、 注入反向直流以及电位补偿的 方法，即：（1)中性点串联电阻；（2)中性点串联电容；（3)线路串联电容； （4)中性 点注入反向直流电流； （5) 直流地电位补偿法。 以上方法均采用简化的电路模 型，忽略了变电站接地网络、 土壤结构、 电网拓扑网络以及变电站变压器的直 流电阻和输电线路的直流电阻等相关影响因素， 导致误差较大。 变电站间的输 电线路是直流电流流通的主要通道， 由于 500kV 站的主变压器多为直接接地运 行方式， 因此当各变电站的直流地电位存在显著差异时， 各变电站主变和站间 线路上会有直流电流通过。 由于 500kV输电线路的直流电阻较小， 所以只要有 较小的电位差就能够激起较大的直流电流。 由于变电站接地电阻、 站间线路直 流电阻和主变绕组直流电阻存在差别， 导致变压器各相流过的直流幅值并不相 同。 常州武南变、 苏州吴江变等站的实测数据结论已证明此结论。
因此， 在电流互感器二次侧开展消除或减小直流偏磁对电流互感器影响的 相关实验研究， 能弥补目前直流偏磁抑制技术的不足， 是亟待研究和开发的新 技术。
发明内容
本发明所要解决的技术问题是： 在电流互感器二次侧消除或减小直流偏磁 对电流互感器影响。
为解决上述技术问题， 本发明采用以下技术方案。
电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 电流互感器 主体的计量铁芯上具有计量绕组和补偿绕组， 所述补偿绕组与直流偏磁自动补 偿装置连接。
前述的电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 所述 计量绕组和补偿绕组为同一铁芯的两个独立线圈， 如图中线圈 K1K2 和线圈 K3K4 , K2K3 不连接）， 或同一铁芯一个线圈的不同抽头 （如图中 K1K2K4 , K2K3 连接）。
前述的电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 直流 偏磁自动补偿装置安装在电流互感器底座上。
前述的电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 所述 直流偏磁自动补偿装置包括标准变换器， 标准变换器串联接入计量绕组二次回 路， 将电流互感器二次侧电流信号转换为电压信号；
标准变换器的输出信号接入阻抗变换电路， 阻抗变换电路具有高输入阻 抗， 使信号传输路径有合适的阻抗匹配；
阻抗变换电路的输出信号经过倍频电路之后转换为倍频信号， 作为相敏检 波的参考信号； 阻抗变换电路的输出信号同时经过带阻滤波电路之后， 作为相 敏检波的输入信号；
倍频电路用于产生相敏检波电路所需的参考信号， 带阻滤波电路用于滤除 工频信号， 增大信噪比；
相敏检波电路用于提取电流互感器二次侧输出信号的偶次谐波信号； 相敏检波电路的输出信号通过低通滤波电路， 滤除相敏检波输出信号的高 频成分， 得到直流成分；
低通滤波的输出信号经负反馈控制器进行计算和负反馈调整后输出。 最终 控制压控电流源输出与一次直流电流成比例的直流补偿电流， 使得二次输出偶 次谐波最小， 此时直流电流作为电流互感器二次侧补偿绕组的补偿电流， 达到 最佳补偿效果， 直流补偿电能能够抵消一次电流直流分量对电流互感器直流偏 磁的影响。
负反馈控制器包括减法器和一个 PID控制器， 输入信号和设定值相减作为 PID调节器的输入， 经 PID调节后， 信号输出。
本发明的工作原理： 本发明设计了电流互感器计量绕组的直流偏磁自动补 偿装置， 电流互感器计量铁芯上具有计量绕组和补偿绕组两个独立绕组， 计量 绕组作为电流互感器正常工作的输出绕组， 而补偿绕组用于注入补偿电流， 以 抵消直流偏磁对电流互感器特性的影响， 从而具有直流偏磁自动补偿功能。 直 流偏磁自动补偿装置用于检测电流互感器二次侧测量绕组输出的偶次谐波分量 的大小及相位， 从而控制直流电流源向电流互感器二次侧补偿绕组注入相应量 的反向直流电流作为补偿电流， 补偿电流在补偿绕组中产生磁场， 抵消一次侧 直流所产生的磁场， 从而实现对电流互感器直流偏磁的自动补偿。
附图说明
图 1 是本发明电流互感器计量绕组的直流偏磁自动补偿装置整体结构示意 图；
图 2 是本发明电流互感器计量绕组的直流偏磁自动补偿装置安装结构示意 图，
图 3是电流互感器计量绕组的直流偏磁自动补偿装置的原理框图； 图 4是电流互感器计量绕组的直流偏磁自动补偿装置的试验接线图； 图 5 是电流互感器计量绕组的直流偏磁自动补偿装置的负反馈控制器原理 框图。
图中： 11-母线， 12-电流互感器， 13-正常计量绕组输出抽头， 14-补偿绕 组抽头， 15-直流偏磁补偿装置， 16-220V电源插头， 17-二次取能线圈。 1-调压器， 2-升流器， 3-直流电流源， 4-电容柜， 5-标准电流互感器， 6-被校 电流互感器， 7-标准信号变换箱， 8-直流偏磁补偿装置， 9 -互感器校验仪。 具体实施方式
结合附图对本发明作进一步的描述。
如图 1 所示， 电流互感器计量铁芯上具有计量绕组和补偿绕组， 其中计量 绕组和补偿绕组可以为同一铁芯的两个独立线圈， 如图 1 中线圈 K1K2 和线圈 K3K4 , K2K3 不连接， 也可以为同一铁芯一个线圈的不同抽头， 如图 1 中 K1K2K4 , K2K3连接。 计量绕组作为电流互感器正常工作的输出绕组， 而补偿绕 组采用多抽头电流互感器的未使用绕组或专为实现补偿作用设计的二次绕组， 用于注入补偿电流。 直流偏磁自动补偿功能的实现， 是通过检测电流互感器二 次侧输出的偶次谐波分量的大小及相位， 控制直流电流源向电流互感器二次侧 补偿绕组注入相应量的反向直流电流作为补偿电流， 补偿电流在补偿绕组中产 生磁场， 抵消一次侧直流所产生的磁场， 从而实现对电流互感器直流偏磁的自 动在线补偿。 整个补偿过程为闭环控制， 第一次补偿如果没有完全消除直流偏 磁的影响， 则互感器二次输出仍有二次谐波分量， 通过检测二次谐波分量， 继 续对直流偏磁进行补偿， 直至输出中不含二次谐波分量为止。
直流偏磁自动补偿技术首先需要检测电流互感器输出的二次谐波含量， 以 此定量评估一次侧直流量， 从而控制电流源产生相应的补偿直流以减小或者抵 消一次侧直流影响。 直流偏磁自动补偿方案的难点主要在于定量获取二次谐波 含量， 并根据二次谐波含量自动产生补偿直流电流。 为此， 设计了电流互感器 直流偏磁自动补偿装置， 采用了标准变换器技术、 阻抗变换技术、 倍频技术、 带阻滤波技术、 基于相乘原理的相敏检波技术、 多级滤波技术、 压控电流源技 术。
标准信号变换器串入计量绕组二次回路， 将电流互感器二次侧电流信号转 换为电压信号， 用于获取电流互感器二次侧电流信号作为直流偏磁自动补偿装 置输入。 该变换器主要起到信号隔离、 获取信号的作用。 为了保证不影响电流 互感器原二次侧负荷， 设计的标准信号变换器通过小 CT 进行隔离， 保证电流 互感器二次侧不会开路， 安全可靠。 小 CT 的二次输出电流接电阻 R 则变换为 电压信号， 作为直流偏磁自动补偿装置输入。 标准信号变换器一次负荷小于 0. 25VA, 负荷很小， 基本不改变电流互感器原二次负荷的分布情况。
标准变换器的输出信号接入阻抗变换电路， 阻抗变换电路具有高输入阻 抗， 使信号传输路径有更合适的阻抗匹配。 阻抗变换后的信号一方面经过倍频 电路之后转换为倍频信号， 作为相敏检波的参考信号； 另一方面经过带阻滤波 电路之后， 作为相敏检波的输入信号。 倍频电路用于产生相敏检波电路所需的 参考信号， 带阻滤波电路用于滤除工频信号， 增大信噪比。 输入信号与参考信 号两路信号作为相敏检波电路的输入信号， 相敏检波电路用于提取电流互感器 二次侧输出信号的偶次谐波信号。 相敏检波电路的输出信号通过低通滤波电 路， 滤除相敏检波输出信号的高频成分， 得到直流成分。 低通滤波之后的信号 经过压控电流源电路， 产生与偶次谐波含量成正比的直流电流， 以此作为电流 互感器二次侧补偿绕组的补偿电流， 以抵消直流偏磁对电流互感器特性的影 响， 从而实现对互感器直流偏磁的自动补偿， 减小直流偏磁对互感器测量精度 直流偏磁自动补偿装置电源供电可以采用一次外接电源供电， 也可以采用 一次线圈取能供电。 当一次电源供电时采用外接电源供电时， 需要用到电源模 块， 能够保证直流偏磁自动补偿装置正常供电。 当一次线圈取能供电时， 则设 计为额定一次电流的 3%开始工作点工作， 当一次电流小于额定值 3%时， 直流 偏磁给互感器带来的测量误差相对于互感器本身在额定 3%测量点误差较小， 则 直流偏磁自动补偿装置停止工作， 不进行直流偏磁补偿。
设计的直流偏磁自动补偿装置在正常工作情况下， 不会影响电流互感器的 正常运行。 下面是正常工况下对电流互感器计量的影响进行的分析。
该装置的输入信号取自电流互感器的二次绕组， 如图 1， 当补偿绕组和计量 绕组相互独立时， 补偿绕组 K3K4 的直流电流不会感应到二次绕组 K1K2; 当补 偿绕组和计量绕组为同一线圈的不同抽头时， 补偿绕组的直流电流只在补偿绕 组 K3K4回路流过， 不会流经二次绕组 K1K2。 补偿绕组 Κ3Κ4接压控电流源， 其 阻抗趋近于无穷大， 因此补偿绕组也不会影响二次绕组交流电流。 因而该装置 在实际运行时不会对电流互感器计量本身产生不利影响。
设计的直流偏磁自动补偿装置在该装置出故障的情况下， 也不会影响电流 互感器的正常运行。 下面是对该装置出现故障情况下对电流互感器计量的影响 进行的分析。
1 ) 电流互感器和补偿装置之间的连线断线
如果互感器和补偿装置之间的连线断线， 如图 1所示， 其中 a点断线， 则 补偿装置的输入信号为 0， 其输出直流也为 0， 此时不对互感器进行补偿。
2 )补偿装置误出直流
直流偏磁电流的大小一般不会超过某一极限， 则补偿装置的输出也不应该 超过此值。 补偿装置电路中设计了保护电路部分（图 l_b )， 当补偿装置输出电 流过大时， 则保护电路动作， 使装置输出为 0， 不进行补偿。 3 )补偿装置供电回路断路或短路
当补偿装置供电回路断路时，如图 1所示， c点断路， 补偿装置没有供电， 则输出直流为 0， 即不补偿。
当供电回路短路时， 由于短路时电流较大， 补偿装置中的供电回路中设计 了相应的熔断器， 短路时自动熔断， 将供电回路断开， 此时补偿装置的输出直 总之， 直流偏磁在线补偿装置即使在出故障的情况下， 最坏的结果就是不 对互感器进行直流偏磁补偿， 但不会影响互感器的正常运行。
图 3 为电流互感器计量绕组的直流偏磁自动补偿装置的原理框图， 主要包 括标准变换器、 阻抗变换电路、 倍频电路、 带阻滤波电路、 相敏检波电路、 低 通滤波电路、 压控电流源电路等。
标准变换器串入计量绕组二次回路， 将电流互感器二次侧电流信号转换为 电压信号。 标准变换器的输出信号接入阻抗变换电路， 阻抗变换电路具有高输 入阻抗， 使信号传输有更合适的阻抗匹配。
阻抗变换后的信号一方面经过经过整形倍频为 Ι ΟΟΗζ , 作为相敏检波的参考 信号； 另一方面经过 50Hz 带阻滤波之后， 作为相敏检波的输入信号。 倍频电 路用于产生相敏检波电路所需的参考信号， 带阻滤波电路用于滤除工频信号， 增大信噪比。
输入信号与参考信号两路信号作为相敏检波电路的输入信号， 相敏检波电 路用于提取电流互感器二次侧输出信号的偶次谐波信号。 相敏检波电路的输出 信号通过低通滤波电路， 滤除相敏检波输出信号的高频成分， 得到直流成分。
低通滤波之后的信号经过压控电流源电路， 产生与偶次谐波含量成正比的 直流电流， 以此作为电流互感器二次侧补偿绕组的补偿电流， 以抵消直流偏磁 对电流互感器特性的影响， 从而实现对互感器直流偏磁的自动补偿， 减小直流 偏磁对互感器测量精度的影响， 提高互感器的测量准确度。
图 4 为电流互感器计量绕组的直流偏磁自动补偿装置的试验接线图。 为了 测试该自动补偿装置的性能， 在设计完成该自动补偿装置之后， 对其性能进行 了验证性试验， 试验按照图 3 的试验接线图接线。 试验用到的设备包括： 1-调 压器， 2-升流器， 3-直流电流源， 4-电容柜， 5-标准电流互感器， 6-被校电流 互感器， 7-标准信号变换箱， 8-直流偏磁补偿装置， 9 -互感器校验仪。 交流 电流源采用调压器 1、 升流器 2 组成， 调压控制升流器输出交流大电流； 直流 电流源 3产生直流电流； 电容柜 4用于隔离直流， 使直流电流不会流过交流升 流器， 同时直流电流源具有高输出阻抗， 使得交流电流流过直流电流源， 因而 标准电流互感器 5将只有交流电流通过， 而本设计的新型电流互感器 6将流过 交流大电流和直流电流的叠加电流， 此时本设计的电流互感器计量绕组的一种 直流偏磁自动补偿装置将会产生直流偏磁。
根据实验接线图， 将被校电流互感器计量绕组输出的电流信号经标准信号 变换箱 7转换为电压信号后接入直流偏磁补偿装置 8， 直流偏磁补偿装置的输 出信号反馈到电流互感器补偿绕组， 使用互感器校验仪 9对同一时刻的标准电 流互感器和本设计的新型电流互感器两路输出信号进行校验， 测试比差、 角 差。 分别对未补偿和补偿线之后的互感器准确度进行测试， 并进行对比。
未加补偿装置时的实验表明， 自动补偿装置能检测出电流互感器偏磁情 况， 其输出的直流电流和一次电流 DC含量有一定比例关系。
加补偿装置后的实验表明， 自动补偿装置通过定量获取偶次谐波含量， 能 够判断互感器偏磁情况， 并输出反向直流电流自动进行补偿， 补偿效果显著。 实验证明， 本设计的电流互感器计量绕组的一种直流偏磁自动补偿装置， 能够实现对直流偏磁的自动补偿， 补偿效果显著。

Claims

权 利 要 求 书
1.电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 电流互感 器主体的计量铁芯上具有计量绕组和补偿绕组， 所述补偿绕组与直流偏磁自动 补偿装置连接。
2.根据权利要求 1 所述的电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 所述计量绕组和补偿绕组为同一铁芯的两个独立线圈， 或同一铁 芯一个线圈的不同抽头。
3.根据权利要求 1 所述的电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 直流偏磁自动补偿装置安装在电流互感器底座上。
4. 根据权利要求 1 所述的电流互感器计量绕组的直流偏磁自动补偿装置， 其特征在于： 所述直流偏磁自动补偿装置包括标准变换器， 标准变换器串联接 入计量绕组二次回路， 将电流互感器二次侧电流信号转换为电压信号；
标准变换器的输出信号接入阻抗变换电路， 阻抗变换电路具有高输入阻 抗， 使信号传输路径有合适的阻抗匹配；
阻抗变换电路的输出信号经过倍频电路之后转换为倍频信号， 作为相敏检 波的参考信号； 阻抗变换电路的输出信号同时经过带阻滤波电路之后， 作为相 敏检波的输入信号；
倍频电路用于产生相敏检波电路所需的参考信号， 带阻滤波电路用于滤除 工频信号， 增大信噪比；
相敏检波电路用于提取电流互感器二次侧输出信号的偶次谐波信号； 相敏检波电路的输出信号通过低通滤波电路， 滤除相敏检波输出信号的高 频成分， 得到直流成分；
低通滤波的输出信号经负反馈控制器进行计算和负反馈调整后输出， 最终 控制压控电流源输出与一次直流电流成比例的直流补偿电流， 使得二次输出偶 次谐波最小。
5. 根据权利要求 4所述的电流互感器计量绕组的直流偏磁自动补偿装 置， 其特征在于： 所述负反馈控制器包括减法器和一个 PID控制器， 输入信号 和设定值相减作为 PID调节器的输入， 经 PID调节后， 信号输出。
PCT/CN2014/079961 2014-03-12 2014-06-16 电流互感器计量绕组的直流偏磁自动补偿装置 WO2015135264A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201410090551.1 2014-03-12
CN201410090551.1A CN103901383B (zh) 2014-03-12 2014-03-12 电流互感器计量绕组的直流偏磁自动补偿装置

Publications (1)

Publication Number Publication Date
WO2015135264A1 true WO2015135264A1 (zh) 2015-09-17

Family

ID=50992833

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2014/079961 WO2015135264A1 (zh) 2014-03-12 2014-06-16 电流互感器计量绕组的直流偏磁自动补偿装置

Country Status (2)

Country Link
CN (1) CN103901383B (zh)
WO (1) WO2015135264A1 (zh)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104810932A (zh) * 2015-03-30 2015-07-29 国家电网公司 一种磁通反馈调节的电流感应取电装置及其方法
CN104897940B (zh) * 2015-06-10 2018-02-16 广州今闰能源科技有限公司 一种穿心式电流互感器
CN107068373B (zh) * 2017-04-28 2020-01-24 中国电力科学研究院 一种抗直流电流互感器
CN108872669B (zh) * 2018-07-05 2020-07-10 合肥工业大学 用于感应分流器的pid控制误差补偿系统及其方法
CN110031666B (zh) * 2019-05-10 2021-04-16 武汉大学 一种直流大电流测量装置及测量方法
US11705275B2 (en) 2019-12-02 2023-07-18 Panoramic Power Ltd. Self calibration by double signal sampling
CN111585358B (zh) * 2020-07-02 2022-05-03 国网山东省电力公司电力科学研究院 专用于微机保护的多类型单绕组线圈供电测量一体化装置
CN113391110A (zh) * 2021-06-21 2021-09-14 陈德才 一种有源抗直流分量的电流互感器
CN113466526B (zh) * 2021-07-27 2022-07-26 河北工业大学 剩余电流传感器电路及断路器
CN115602430B (zh) * 2022-12-15 2023-04-18 清华四川能源互联网研究院 一种基于铁芯磁化补偿的谐波抑制装置和方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000266785A (ja) * 1999-03-15 2000-09-29 Matsushita Electric Works Ltd 電流計測装置
CN101800598A (zh) * 2010-02-08 2010-08-11 北京信息科技大学 新的mz外调制器平衡检测偏置控制方法
CN102426343A (zh) * 2011-08-31 2012-04-25 中国科学院上海微系统与信息技术研究所 基于squid偏置电压反转的读出电路及低频噪声的抑制方法
CN102522190A (zh) * 2011-12-02 2012-06-27 沈阳工业大学 具有直流偏磁补偿能力的电力变压器及工作方法
CN102545222A (zh) * 2011-12-21 2012-07-04 武汉理工大学 基于线路3次谐波的分布式潮流控制器
CN102866283A (zh) * 2012-09-12 2013-01-09 北京东方计量测试研究所 一种叠加大直流偏置的交流电流的测量装置

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4847554A (en) * 1987-03-04 1989-07-11 Sangamo Weston, Inc. Current measuring and magnetic core compensating apparatus and method
CN101872005B (zh) * 2010-06-04 2012-10-31 中国计量学院 带升流器的电子式周期性非正弦波基准电流互感器
CN202127244U (zh) * 2011-07-12 2012-01-25 张航生 一种电流控制型有源谐波治理和有源无功补偿装置
CN203720342U (zh) * 2014-03-12 2014-07-16 国家电网公司 电流互感器计量绕组的直流偏磁自动补偿装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000266785A (ja) * 1999-03-15 2000-09-29 Matsushita Electric Works Ltd 電流計測装置
CN101800598A (zh) * 2010-02-08 2010-08-11 北京信息科技大学 新的mz外调制器平衡检测偏置控制方法
CN102426343A (zh) * 2011-08-31 2012-04-25 中国科学院上海微系统与信息技术研究所 基于squid偏置电压反转的读出电路及低频噪声的抑制方法
CN102522190A (zh) * 2011-12-02 2012-06-27 沈阳工业大学 具有直流偏磁补偿能力的电力变压器及工作方法
CN102545222A (zh) * 2011-12-21 2012-07-04 武汉理工大学 基于线路3次谐波的分布式潮流控制器
CN102866283A (zh) * 2012-09-12 2013-01-09 北京东方计量测试研究所 一种叠加大直流偏置的交流电流的测量装置

Also Published As

Publication number Publication date
CN103901383A (zh) 2014-07-02
CN103901383B (zh) 2016-08-17

Similar Documents

Publication Publication Date Title
WO2015135264A1 (zh) 电流互感器计量绕组的直流偏磁自动补偿装置
CN203720342U (zh) 电流互感器计量绕组的直流偏磁自动补偿装置
US9568532B2 (en) Wind turbine fault detection circuit and method
CA2800551C (en) Method and apparatus for detecting a magnetic characteristic variable in a core
Buticchi et al. Detection method of the DC bias in distribution power transformers
CN105870929B (zh) 一种抑制船舶变压器励磁涌流的装置和方法
CN106655144A (zh) 基于双闭环控制的配电网故障有源电压消弧方法及装置
CN108023345B (zh) 一种配电网有源消弧装置电压控制方法
CN110544930B (zh) 一种基于电容电流的电压跌落调整系统及方法
Tian et al. Arc-suppression coil based on transformer with controlled load
CN110571778A (zh) 一种自产供电相电源的接地故障电流补偿系统及方法
CN112363031A (zh) 电磁式电压互感器的一次侧绕组杂散电容测量方法
CN109995044A (zh) 配电网中性点位移电压有源抑制的双闭环控制方法
CN104483639B (zh) YNd11型三相组式变压器非故障跳闸的剩磁估计方法
Oliveira et al. Application of Park's power components to the differential protection of three-phase transformers
Zhao et al. Online Identification of High-Frequency Transformer Short-Circuit Parameters Based on Instantaneous Phasor Method
Gao et al. A transformer flux balancing scheme based on magnetizing current harmonic in dual-active-bridge converters
US11563317B1 (en) Double grounded neutral fault detection
Li et al. Harmonic distortion feature of AC transformers caused by DC bias
CN111103499A (zh) 一种经消弧线圈串联电阻接地配电网对地参数测量方法
Naghshbandy et al. Blocking DC flux due to geomagnetically induced currents in the power network transformers
CN112526411B (zh) 一种磁控式并联电抗器绕组匝间故障检测方法及系统
KR101447703B1 (ko) 3상 6펄스 정류에서 발생하는 고조파를 감소시키는 광대역 수동형 고조파필터
CN112731013A (zh) 一种用于低压电器产品检测的电波暗室交直流多磁路装置
CN206975165U (zh) 一种小电流同步信号传感器装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14885086

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14885086

Country of ref document: EP

Kind code of ref document: A1