CN203949980U - The charged detector of capacitance type potential transformer - Google Patents

Abstract

The utility model relates to the charged detector of a kind of 220kV capacitance type potential transformer (CVT), comprises current unit, voltage cell, notebook computer, and voltage cell is used for measuring CVT bus PT voltage U _mW, current unit is used for measuring CVT measuring junction voltage U _cVT, flow through C2 electric current I _c2with flow through CVT intermediate transformer electric current I _t.The utility model without CVT equipment in transformer station is carried out any type of power failure operation, early stage retrofit work.Use high precision split core type current transformer, easy-to-connect safety, does not affect CVT equipment to be measured and normally moves during work.CVT many kinds of parameters to be measured can be provided, can carry out multiparameter assessment to CVT overall operation state, there is professional CVT status assessing system.

Description

The charged detector of capacitance type potential transformer

Technical field

The utility model relates to the charged detector of a kind of 220kV capacitance type potential transformer (CVT), adopts high precision split core type current transformer, does not affect 220kVCVT equipment to be measured and normally move during band electro-detection.

Background technology

Since nineteen ninety-five, domestic CVT volume of production and marketing on average with 25%/year rapid growth.Along with the increase of CVT usage quantity, the number of times that CVT breaks down becomes ascendant trend year by year.Therefore, improving CVT site examining and repairing detectability, is very significant.

CVT equipment incipient fault problem for day by day highlighting, there is no solid detection means at present.According to the Q/GDW168-2008 < < of State Grid Corporation of China power transmission and transformation equipment state overhauling testing regulations > > requirement, at present can only be with visual examination, IR thermal imaging inspection, and periodic routine test, comprise means or the tests such as voltage-dividing capacitor size, Dielectric Loss Test, Secondary Winding insulation resistance, judge the operation conditions of CVT.But practical experience shows, above-mentioned power failure detection means is also not enough to the problem of finding that CVT is potential.

Last decade, due to the progress of computer and sensor technology, people adopt punching current transformer, have developed the charged on-line monitoring system of capacitive apparatus, but this monitoring system need to change end shield lead-in wire, and once investment is large, secondary maintenance expense is high, overall test result is undesirable too.Due to these shortcomings, in the urgent need to the research and development of the Novel belt electrical testing instrument for CVT.

Utility model content

The purpose of this utility model is to provide the charged detector of a kind of capacitance type potential transformer.

Technical solutions of the utility model: the charged detector of a kind of capacitance type potential transformer, comprises current unit, voltage cell, notebook computer, described voltage cell: for measuring CVT bus PT voltage U _mW, U _mWsignal passes through ADC signal processing module with the reference signal that reference source signal generator produces through voltage sensor after amplification filtering module again, simulating signal is converted into can be by the digital signal of machine recognition, in programmable gate array FPGA input single-chip microprocessor MCU, store again, through FPGA and communication interface and current unit, communicate simultaneously, then through USB, turn RS485 serial ports and be transferred in notebook computer;

Described current unit: for measuring CVT measuring junction voltage U _cVT, flow through C2 electric current I _c2with flow through CVT intermediate transformer electric current I _t, U _cVTsignal arrives amplification filtering module, I through voltage sensor _c2, I _tthe reference signal that signal produces to amplification filtering module and with reference source signal generator through current sensor is respectively through ADC signal processing module, simulating signal is converted into can be by the digital signal of machine recognition, in programmable gate array FPGA input single-chip microprocessor MCU, store again, through FPGA and communication interface and notebook computer, communicate simultaneously, the signal collecting is directly turned to RS485 serial ports through USB and be transferred in notebook computer; C ₂for CVT low-voltage arm dividing potential drop electric capacity.

Good effect of the present utility model:

The utility model is a live testing instrument, lightweight, and with using with walking, behaviour does simple, without CVT equipment in transformer station being carried out to any type of power failure operation, early stage retrofit work.Same equipment, can be used for the measurement of different electric pressure CVT.The utility model is used high precision split core type current transformer, and easy-to-connect safety, does not affect CVT equipment to be measured and normally move during work.The utility model can provide CVT many kinds of parameters to be measured, can carry out multiparameter assessment to CVT overall operation state, has professional CVT status assessing system.Except each dividing potential drop capacitance parameter of Measurement accuracy, propose for the first time to utilize the amplitude of CVT voltage and busbar voltage and the slight change of phase angle difference to assess the defects such as electric capacity and dielectric loss in CVT, transformer is deteriorated, solve dielectric loss and be subject to ambient temperature and humidity to affect greatly, test inaccurate and cause the insecure problem of conclusion.

Accompanying drawing explanation

Fig. 1 is the utility model block diagram.

Fig. 2 is the utility model voltage cell block scheme.

Fig. 3 is the utility model current unit block scheme.

Fig. 4 is the utility model and CVT field wiring figure.

In figure, each variable declaration is as follows:

I _c2----flow through CVT low-voltage arm C ₂electric current, is obtained by high precision split core type current transformer;

I _t-----the CVT intermediate transformer electric current of flowing through, is obtained by high precision split core type current transformer;

U _cVT---CVT intermediate transformer secondary output voltage, is obtained by high-accuracy voltage mutual inductor;

U _mW----bus PT output voltage, is obtained by high-accuracy voltage mutual inductor.

Embodiment

As shown in drawings, CVT belt electro-detection instrument comprises current unit, voltage cell, three parts of notebook computer, sees Fig. 1.Between unit, adopt shielding netting wire to be used for signal transmission between unit, use shielded cable to switch on to voltage cell, use 485 buses and USB to turn the information transmission that 485 serial ports are realized electric current, voltage cell and computer.

Voltage cell: for measuring bus PT voltage U _mW, U _mWthrough voltage sensor, after amplification filtering, process through ADC signal with the reference signal of reference source signal generator generation, simulating signal is converted into can be by the digital signal of machine recognition, in field programmable gate array (FPGA) input single-chip microcomputer (MCU), store again, through FPGA and communication interface and current unit, communicate, then through USB, turn RS485 serial ports and be transferred in notebook computer.Reference signal is by the stable power-frequency voltage of the reference source signal generator generation of voltage cell inside, for tracer signal sampling instant, eliminates the error that voltage cell and current unit non-synchronous sampling bring, and voltage cell schematic diagram is shown in Fig. 2.

Current unit: for measuring CVT measuring junction voltage U _cVT, flow through C2 electric current I _c2with flow through CVT intermediate transformer electric current I _tzhe San road signal is processed through ADC signal to amplification filtering device and with the reference signal that reference source signal generator produces through voltage sensor or current sensor, simulating signal is converted into can be by the digital signal of machine recognition, in field programmable gate array (FPGA) input single-chip microcomputer (MCU), store again, through FPGA and communication interface and notebook computer, communicate, the signal collecting is directly turned to RS485 serial ports through USB and be transferred in notebook computer.The reference source signal generator of current unit inside also produces the signal with voltage cell reference source signal synchronous base, the error of bringing for eliminating two unit non-synchronous samplings, and current unit schematic diagram is shown in Fig. 3.

The utility model is a 220kVCVT state of insulation testing instrument for electrified, without under power-off condition, by high-accuracy voltage mutual inductor, high precision split core type current transformer and the simultaneous techniques (reference signal that use device self produces, the sampling time of eliminating between each signal is poor, thereby reach the effect that each signal is sampled simultaneously) obtain CVT voltage, current waveform, the Measurement accuracy of realization to CVT many kinds of parameters, and then realize the accurate evaluation to CVT state of insulation.

Propose for the first time to utilize the amplitude of CVT voltage and busbar voltage and the slight change of phase angle difference to assess the defects such as CVT electric capacity and dielectric loss, transformer be deteriorated, solve dielectric loss be subject to humiture environmental impact large, test inaccurate and cause the insecure problem of conclusion.

CVT belt electrical measurement field wiring figure as shown in Figure 4.

CVT high-voltage arm C ₁by capacitor C ₁₁, C ₁₂be composed in series C ₂for low-voltage arm dividing potential drop electric capacity.L is compensation reactor, and BL is MOV lightning arrester, and T is intermediate transformer, and a-n is measuring junction, and precision is generally 0.5 grade, and da-dn is protection Voltage-output, and precision is generally 3P, a-n termination Quick saturation damper Z _n(damping resistance and the nonlinear inductance that comprise 1.5 Ω).

In Fig. 4, dotted portion is the charged detector of 220kV capacitance type potential transformer (CVT).

Operation steps:

(1) at substation field, according to shown in Fig. 4 by professional electricity operator's correct wiring.

(2) open notebook computer and open test procedure (measurement of sampled signal amplitude, phase angle and detection parameter being calculated for realizing), ready.

(3) connecting alternating current 220V power supply powers on to device.

(4) start test, this device can be measured I simultaneously _t, I _c2, U _cVT, U _mWfour road signals.Calculate busbar voltage fundamental frequency f, calculate I simultaneously _t, I _c2, U _cVT, U _mWsignal fundamental frequency amplitude (effective value) and phase angle, then utilize respective formula to calculate CVT total capacitance C, high-voltage arm dividing potential drop capacitor C on this basis ₁, low-voltage arm dividing potential drop capacitor C ₂, U ₂/ U _mW, φ ₁(U ₂with U _mWangular difference), C/C ₀, C ₁/ C ₁₀, C ₂/ C ₂₀(C ₁₀, C ₂₀be respectively C in CVT ₁, C ₂rated capacity value, C ₀for C ₁₀, C ₂₀series value, C is C ₁, C ₂measure series value).

(5) by each measurement parameter assessment CVT overall operation state.

(6) clear up in accordance with regulations CVT belt electric detection means, test finishes.

Claims (1)

1. the charged detector of capacitance type potential transformer, is characterized in that: comprise current unit, voltage cell, notebook computer, described voltage cell: for measuring CVT bus PT voltage U _mW, U _mWsignal passes through ADC signal processing module with the reference signal that reference source signal generator produces through voltage sensor after amplification filtering module again, simulating signal is converted into can be by the digital signal of machine recognition, in programmable gate array FPGA input single-chip microprocessor MCU, store again, through FPGA and communication interface and current unit, communicate simultaneously, then through USB, turn RS485 serial ports and be transferred in notebook computer;

Described current unit: for measuring CVT measuring junction voltage U _cVT, flow through C2 electric current I _c2with flow through CVT intermediate transformer electric current I _t, U _cVTsignal arrives amplification filtering module, I through voltage sensor _c2, I _tthe reference signal that signal produces to amplification filtering module and with reference source signal generator through current sensor is respectively through ADC signal processing module, simulating signal is converted into can be by the digital signal of machine recognition, in programmable gate array FPGA input single-chip microprocessor MCU, store again, through FPGA and communication interface and notebook computer, communicate simultaneously, the signal collecting is directly turned to RS485 serial ports through USB and be transferred in notebook computer; C ₂for CVT low-voltage arm dividing potential drop electric capacity.