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Low-current grounding capacitance current online measurement system

A low-current grounding, capacitive current technology, applied in voltage/current isolation, using digital measurement technology for measurement, changing range circuits, etc. The effect of voltage measurement level, saving operation and maintenance costs, and improving compensation effect

Pending Publication Date: 2020-06-05
CHANGCHUN POWER SUPPLY COMPANY OF STATE GRID JILINSHENG ELECTRIC POWER SUPPLY +2
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  • Abstract
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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a small current grounding capacitive current online measurement system for the above-mentioned technical deficiencies. This system adopts the improved maximum displacement for the two states of whether the neutral point of the small current grounding system is grounded or not. The voltage method and the signal injection method are used to measure and calculate the ground capacitance current, which improves the measurement efficiency of the system capacitance current; secondly, the system proposes the method of capacitance current mixing algorithm by establishing the displacement voltage method control theory based on the arc suppression coil, and solves the problem of There are errors in the traditional capacitive current calculation method, which affects the compensation effect of the arc suppression coil, and achieves the technical effect of improving the compensation accuracy of the arc suppression coil; and for the problem of large variation range of zero-sequence current and voltage, a displacement voltage'dual channel, High-precision' measurement method, by adopting high and low ranges, achieves the technical effect of improving the measurement level of displacement voltage and capacitive current; finally, the present invention adopts the theory and technology of signal injection method to measure capacitive current by improving the establishment of neutral point ungrounded system Established to eliminate the problem that the capacitive current cannot be measured when the neutral point is not grounded, and achieve the measurement effect of the capacitive current under all working conditions

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  • Low-current grounding capacitance current online measurement system

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specific Embodiment approach 1

[0042] Embodiment 1: When the switch S in the arc suppressing coil 3 is closed, that is, when the arc suppressing coil 3 is put into operation, the improved maximum displacement voltage method is used to measure and calculate the small current grounding capacitor current, combined with Figure 8 The measurement flow chart shown, the main steps are as follows:

[0043] Step 1: The central control device 7 is put into operation through the inductance control device 5, and the signal injection device 6 is closed; if figure 1 As shown, at this moment, the inductance control device 5 controls the arc suppression coil 3 to complete the measurement of the capacitive current;

[0044] Step 2: If Figure 5 , the stepper motor inside the inductance control device 5 is connected to control the adjustable inductance L of the arc suppression coil 3. During the process of increasing the arc suppression coil L, the arc suppression coil is controlled by the high and low range voltage sensor ...

specific Embodiment approach 2

[0057] Specific embodiment two: when the switch S in the arc suppressing coil 3 is turned off, that is, when the arc suppressing coil 3 is not put into operation, the improved maximum displacement voltage method cannot be used to measure and calculate the small current grounding capacitor current at this time, so it can be used The signal injection method is used to measure the capacitive current, combined with Figure 12 The measurement flow chart shown, the main steps are as follows:.

[0058] Step 1: The central control device 7 is put into operation through the signal injection device 6, and the inductance control device 5 is turned off; if figure 1 As shown, at this time, the signal injection device 6 performs signal injection to the grid line 1 to complete the measurement of the capacitive current;

[0059] Step 2: If Figure 7 , the voltage transformer 305 in the measurement unit 12 of the injection device measures the system frequency and the displacement voltage U ...

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Abstract

The invention relates to the technical field of low-current grounding capacitance current measurement, and specially relates to a low-current grounding capacitance current online measurement system. Aiming at two states that whether a neutral point of a small-current grounding system is grounded or not, an improved maximum displacement voltage method and a signal injection method are respectivelyadopted to measure and calculate the grounding capacitance current, so that the measurement efficiency of the capacitance current of the system and the all-working-condition operation capability are improved; secondly, by establishing a displacement voltage method control theory based on the arc suppression coil, a method of a capacitive current hybrid algorithm is provided by the system, the problems that errors exist in a traditional capacitive current calculation method and the compensation effect of the arc suppression coil is affected are solved, and the technical effect of improving thecompensation precision of the arc suppression coil is achieved; and aiming at the problem of large zero-sequence current and voltage change range, a displacement voltage dual-channel and high-precision measurement method is provided, and the technical effect of improving the measurement level of the displacement voltage and the capacitance current is achieved by adopting a high-range and low-rangemode.

Description

technical field [0001] The invention relates to the technical field of small current grounding capacitance current measurement, in particular to an online measurement system for small current grounding capacitance current. Background technique [0002] With the expansion of the urban power grid and the increase of cable outlets, the capacitive current of the system increases greatly. When a single-phase grounding fault occurs in the system, the grounding arc cannot be self-extinguished, and it is easy to generate intermittent arcing grounding overvoltage. If it lasts for a long time, it will develop into a two-phase short circuit accident at the weak point of the line insulation. Therefore, when the network is large enough, it is necessary to use the arc suppression coil to compensate the capacitive current, which is one of the important technical measures to ensure the safe operation of the power system. In order to avoid the threat of improper compensation to the safe ope...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R19/25G01R15/18G01R15/08
CPCG01R15/08G01R15/18G01R19/25
Inventor 王国友鲁宸邢亮徐伟进胡囯龙李伟霞李东有韩海峰于颢明罗鑫王禹潼梁青黄逸宁贾春成李琪鸿
Owner CHANGCHUN POWER SUPPLY COMPANY OF STATE GRID JILINSHENG ELECTRIC POWER SUPPLY
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