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A method for detecting capacitor capacitance attenuation

A detection method and capacitor technology, applied in instruments, measuring devices, measuring electrical variables, etc., can solve the problems of low capacitance current accuracy, huge workload, affecting current measurement values, etc., to improve manual detection accuracy and save human resources. , to ensure the effect of real-time

Active Publication Date: 2021-04-06
ZHEJIANG NANDA ELECTRICAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, this detection method in the prior art requires the operator of the power distribution room to open the capacitor cabinet door regularly, and manually detects and compares the rated current value with a clamp ammeter when the capacitor is put into operation, which improves the operator's safety. Safety protection and professional level requirements
At the same time, there are generally multiple groups of capacitors in the capacitor cabinet, and each group of capacitors needs to be measured, so the workload is huge
Moreover, since the fluctuation of the grid voltage and the harmonic voltage and current will affect the measured value of the current, the accuracy of the capacitive current detected by the clamp ammeter is low
[0005] In addition, the attenuation and change of the capacitance value of the capacitor may be a long-term slow process, or a qualitative change may occur suddenly. Therefore, the method of manual measurement is a waste of human resources and time-consuming

Method used

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  • A method for detecting capacitor capacitance attenuation
  • A method for detecting capacitor capacitance attenuation

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Embodiment 1

[0034] This embodiment provides a capacitor capacitance attenuation detection method, which is used to measure the capacitance attenuation ratio of a three-phase split-compensation capacitor. The principle block diagram of the circuit used is as follows figure 1 Shown:

[0035]In the circuit used in this embodiment, phase A, phase B and phase C are connected in a star shape, and the power supply circuit 2 supplies power. The power supply circuit 2 is a commonly used power supply circuit in the field, including transformers, rectifiers, voltage regulators and other components, which belong to the prior art in the field and are not limited here. A first capacitor 11 is connected in parallel between the A phase and the zero phase, a second capacitor 12 is connected in parallel between the B phase and the zero phase, a third capacitor 13 is connected in parallel between the C phase and the zero phase, the first capacitor 11, The second capacitor 12 and the third capacitor 13 toge...

Embodiment 2

[0051] The difference between this embodiment and the first embodiment is that each phase of the three-phase split compensation capacitor 1 is connected with a reactor in series. Specifically in this embodiment, phase A is connected in series with a first reactor 14 , phase B is connected in series with a second reactor 15 , and phase C is connected in series with a third reactor 16 . After the reactor is connected in series, the relationship between the rated voltage, rated capacity and the effective value of the rated fundamental wave current in step 3 is: Among them, U 2 is the rated voltage, Q 2 is the rated capacity, I 2 is the effective value of the rated fundamental wave current, K is the reactance rate, and the reactance rate is the ratio of the reactance value of the reactor to the capacitive reactance value of the three-phase split compensation capacitor.

[0052] In this embodiment, each phase is connected in series with a reactor, which can filter out harmonics...

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Abstract

The invention discloses a capacitor capacitance attenuation detection method, which relates to the field of low-voltage power capacitors and comprises the following steps: detecting the current waveform data of each phase, calculating the current fundamental current effective value of the phase; detecting the voltage waveform of each phase Data, calculate the current effective value of the fundamental wave voltage of the phase; calculate the effective value of the rated fundamental wave current of each capacitor corresponding to the phase; calculate the current effective value of the fundamental wave current under the rated voltage of each phase; The effective value of the fundamental wave current is divided by the rated fundamental wave current effective value of the phase to obtain the capacitance attenuation ratio. The method provided by the invention does not need manual detection and has high precision.

Description

【Technical field】 [0001] The invention belongs to the field of low-voltage power capacitors, in particular to a method for detecting capacitor capacitance decay. 【Background technique】 [0002] In the prior art, low-voltage shunt capacitors are basically "self-healing" metal film capacitors, which can be automatically repaired when a breakdown or leakage fault occurs. However, the capacity of the capacitor may be reduced. If the capacity of the capacitor does not drop much and the three-phase is basically balanced, it can continue to be put into operation. If the capacity of the capacitor drops too much or the three-phase capacitance is unbalanced, it must be replaced with a new one. [0003] An attenuated capacitor will have a current value lower than the rated current value. Therefore, in order to know whether the capacitance value of the capacitor being put into operation is reduced, the prior art generally uses a clamp-on ammeter to manually check the operating curren...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R27/26
Inventor 郑坚王奔戴珏珺李琦陈潇
Owner ZHEJIANG NANDA ELECTRICAL