Harmonic measuring device and system based on capacitive voltage transformer
A technology of voltage transformer and measuring device, applied in the field of electric power, can solve the problems of inaccurate harmonic voltage and poor harmonic measurement accuracy, and achieve the effect of accurate detection and accurate calculation results.
Inactive Publication Date: 2019-04-02
JIANGSU ELECTRIC POWER CO +1
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Problems solved by technology
The equipment is mainly composed of a voltage dividing capacitor unit and an electromagnetic voltage transformer unit (Potential Transformer, PT). Compared with the traditional PT, the whole set of equipment is small in size, good in insulation performance, and relatively cheap in price. However, considering the broadband transmission of CVT Features It is far inferior to traditional PT measurement in terms of harmonic measurement accuracy
Specifically, the harmonic voltage will be distorted after being transmitted to the secondary side through the CVT, so the harmonic voltage detected on the secondary side of the CVT will be inaccurate
Method used
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Embodiment Construction
[0030] Now in conjunction with the accompanying drawings, the preferred embodiments of the present invention will be described in detail.
[0031] figure 1 It is a schematic diagram of the system composed of capacitive voltage transformer, harmonic measuring device and host computer.
[0032] The capacitive voltage transformer includes a high-voltage capacitor C1, a low-voltage capacitor C2, an electromagnetic unit L, and an intermediate transformer T. The two ends of the high-voltage capacitor C1 are respectively connected to the high-voltage side and the first end of the low-voltage capacitor C2 through wires. The second end of the low-voltage capacitor C2 is grounded through a wire, and one end of the primary coil of the intermediate transformer T is connected to the first end of the low-voltage capacitor C2 through the wire and the electromagnetic unit L, and the other end is connected to the ground.
[0033] The harmonic measurement device 1 includes a first clamp curren...
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The invention discloses a harmonic measuring device and system based on a capacitive voltage transformer. The harmonic measuring device comprises a first current transformer, a second current transformer and a measuring module. The measuring module is configured to detect the first current transformer to obtain a first current and detect the second current transformer to obtain a second current, calculating the sum of the first current and the second current to obtain a third current flowing through a high-voltage capacitor, carrying out Fourier decomposition on the first current to obtain each harmonic current component of the first current, carrying out Fourier decomposition on the third current to obtain each harmonic current component of the third current, and calculating the corresponding number of times of harmonic voltages at a high-voltage side. According to the invention, the currents flowing through a low-voltage capacitor and one side of a primary coil of a CVT transformer are detected, Fourier transform is carried out to obtain harmonic currents, and then the harmonic voltage of the high-voltage side is calculated. The calculation result is accurate.
Description
technical field [0001] The invention relates to the field of electric power technology, in particular to a harmonic measurement device and system based on a capacitive voltage transformer. Background technique [0002] In recent years, with the rapid development of large-capacity power electronic equipment, the grid-connected voltage level of substations has continued to rise. Since there are a large number of inverter and rectifier equipment, it is inevitable to introduce harmonics on the high-voltage side of the grid-connected point. At present, the transformers used as secondary side sampling, measurement and protection equipment in 110kV and above power systems at home and abroad are mainly CVT. The equipment is mainly composed of a voltage dividing capacitor unit and an electromagnetic potential transformer unit (Potential Transformer, PT). Compared with the traditional PT, the whole set of equipment is small in size, good in insulation performance, and relatively cheap...
Claims
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Login to View More IPC IPC(8): G01R35/02
CPCG01R35/02
Inventor 许建明徐懿马振国刘晓康朱海宇苏佳华许霖贾霖
Owner JIANGSU ELECTRIC POWER CO