CN2395281Y

CN2395281Y - Monitor for workaing condition of arrester

Info

Publication number: CN2395281Y
Application number: CN 99242617
Authority: CN
Inventors: 侯建民
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-09-02
Filing date: 1999-09-02
Publication date: 2000-09-06
Anticipated expiration: 2009-09-02

Abstract

The utility model relates to a monitor for working conditions of a lightning arrester, which is used for detecting the leakage current of the lightning arrester and recording the action frequency of the lightning strike of the lightning arrester. The utility model comprises a ground lead of the lightning arrester, a detection circuit, an alternate current amplifying circuit and a linear rectification circuit. One path of the output of the linear rectification circuit is connected with a direct current amplifying circuit to a milliampere meter, and the other path is connected with a counting circuit to a display diode. In the signal detection circuit, a ground lead of the lightning arrester is regarded as a good conductor and passes through an annular core coil. The counting circuit is an electronic counter which is composed of a comparator, a pulse distributor, a driver and a display device. The utility model has the advantages that the frequency of leakage current and lightning strike is recorded accurately, and the signal detection has no influence on the technical parameter of the original lightning arrester.

Description

The lightning arrester performance monitor

The utility model belongs to electrical technology field, relates to the electric system lightning protection, specifically is meant a kind of lightning arrester performance monitor.

Lightning arrester is to guarantee in the electric system that power circuit and important electric equipment exempt from thunderbolt and superpotential infringement, keep the critical component of power system safety and stability operation, thereby, monitor the leakage current of lightning arrester, record thunderbolt action frequency is vital, before the utility model, Chinese patent 93111792, disclosing a kind of lightning arrester leakance detects and discharge counter, it is characterized in that on the arrester ground line, disconnecting, seal in a joint and the identical arrester valve piece made of tested lightning arrester feature, force leakage current of an arrester at ordinary times to flow through and valve block and the milliammeter that connects, when thunderbolt punctures valve block, shove and be bled into ground, simultaneously note the Lightning Over-voltage action frequency by message register, this scheme is simple, not power consumption at ordinary times, but still there is following deficiency: one, discreteness because of sealing in valve block parameter, increased the uncertain factor of leaking performance, and main, the most direct negative effect is the lower limit that has artificially improved the lightning arrester operation voltage, has changed the electric parameter in former arrester ground loop, they are two years old, electromagnetic counter, the normal phase is under the rugged surroundings, and mechanical fault easily takes place.

The purpose of the utility model is to overcome that above-mentioned lightning arrester leakance detects and the deficiency of discharge counter, designs a kind of novel lightning arrester performance monitor.

For reaching above-mentioned purpose, the technical scheme of being taked is, the utility model comprises the signal deteching circuit (1) of going up detection signal from the arrester ground lead-in wire, detection signal is through AC amplifier (2), export linear rectification circuit (3) to, after the rectification, the one tunnel through dc amplification circuit (4), export reometer indication electric leakage numerical value to, another road shows the thunderbolt action frequency through counting circuit (5) record.

Its testing circuit of the utility model (1) is one arrester ground lead-in wire is passed wherein ring-like ironcore choke, detection be mutual inductance signal, kept the arrester ground loop parameter constant, do not influence the lightning arrester technical feature; Counter (5) constitutes full electronic by comparer (6), pulsqe distributor (7), driver (8) and display device, has avoided the generation of electromagnetic mechanical fault.

The relevant accompanying drawing of the utility model

Fig. 1, the utility model electricity functional-block diagram

Fig. 2, the utility model electrical schematic diagram

Fig. 1, the utility model electricity functional-block diagram shows the basic circuit formula of this device, comprise: the ground lead of lightning arrester (10), and current transformer is set in ground lead, constitute signal deteching circuit (1), this current transformer, be by ring-like M unshakable in one's determination, coiling secondary coil n2 on it, ground lead n1 passes ring-like formation unshakable in one's determination, testing circuit (1) connects ac amplifier circuit (2) successively, linear rectification circuit (3), dc amplification circuit (4), export reometer (milliammeter) indication leakage current numerical value to, simultaneously, the output of linear rectification circuit (3) also connects comparer (6) successively, pulsqe distributor (7), driver (8), to display device demonstration thunderbolt number of times.For foregoing circuit provides electric energy is power supply (9), and except that the testing circuit mutual inductor was located at arrester ground lead-in wire place, remaining circuit was by being loaded in the housing (11), for avoiding interference the employing metal shell.

Fig. 2 is the utility model electrical schematic diagram, also is the utility model preferred forms, and details are as follows:

Arrester ground lead-in wire is established signal deteching circuit, i.e. current transformer, and primary coil n1 is ground lead, during practical application, is to go here and there one section lead-in wire of ring-like iron core with the copper rod of good conductor; Detection signal inputs to ac amplifier circuit (2) and amplifies, and this ac amplifier circuit (2) is an operational amplifier, promptly is made of difference direct current amplifier K1 and shunt voltage negative feedback resistor R2, and enlargement factor depends on the ratio of R2 and R1; Signal after the amplification exports linear rectification circuit (3) to, this circuit comprises difference direct current amplifier K2, diode D1, feedback line G and charge and discharge capacitance C1 constitute, feeder line G draws back inverting input with diode output and makes reference voltage, this voltage is dynamic, the prime alternating current output signal connects in-phase input end, constitute a dynamic following comparer, by this comparer and diode, AC signal is become transfer wide positive square-wave signal, its square width is corresponding with prime AC sine wave signal amplitude, this square wave is through the output of capacitor C 1 and front and back stages thereof, the T mode filter that input resistance constitutes, become direct current through smothing filtering, and dc pulse changes and prime AC signal amplitude is linear; Direct current signal after the line rectification exports reometer to through dc amplification circuit (4), dc amplification circuit (4) is continued by difference direct current amplifier K3 and feedback net and constitutes, to be resistance R 5 be in parallel and the connecting of R4 with diode D2 this feedback network again, utilize the non-linear of diode forward volt-ampere characteristic, with diode as a variable resistor, thereby adjust the amplification letter number of amplifier, remedy because of the non-linear alternating signal amplitude distortion that causes of testing circuit mutual inductor magnetic hysteresis unshakable in one's determination; Another road connection count circuit (5) of linear rectification circuit output, this counting circuit is by comparer (6), connect pulsqe distributor (7) successively, driver (8), export to and show that diode constitutes, comparer (6) is by difference direct current amplifier K4 and divider resistance R8, formations such as R9, the ratio decision comparator reference voltage of R8 and R9, and the ratio of R6 and R7 decision comparative voltage, technical parameter according to valve block arrester, the normal condition leakage current is 0-5mA, during superpotential, breakdown current is 〉=40mA-50kA, and the H point voltage value after the pairing rectification is 0-0.3V just often, during thunderbolt 〉=2.4V (present embodiment design data), in view of the above, the reference voltage that comparer (6) can be set be 2V (power supply for ± 3.6V), comparative voltage is through R6, after the R7 dividing potential drop＞2V is promptly turning, so, have only leakage current when normal operation, the H point is＜0.3V that comparer does not overturn, counting circuit is not worked, and this leakage current only is amplified to milliammeter through direct current and indicates; When superpotential, valve block punctures, H point current potential＞2.4V, comparer in-phase input end＞2V is greater than the inverting input reference voltage, the comparer upset, export a noble potential pulse, make pulsqe distributor (6) carry once, for example former 1 end is a noble potential, 1 end step-down after the carry, 2 ends uprise, and this pulsqe distributor internal circuit is numeration, decoding scheme adopts existing integrated circuit CD4017, the output terminal that current potential is high will make the drive circuit works of joining with this end, make corresponding lumination of light emitting diode, promptly 1 signal lamp goes out, and 2 signal lamps are bright, illustrate and be struck by lightning 2 times that driver is integrated circuit MC1413.The utility model is selected the accurate four-operational amplifier LM124 of low-power consumption integration member for use, finishes the function of above-mentioned direct current amplifier K1, K2, K3, K4.

Claims

1, a kind of lightning arrester performance monitor that is used for lightning arrester leakance detection and record lightning arrester thunderbolt action frequency, the ground lead that comprises lightning arrester (10), be characterised in that, also comprise the signal deteching circuit (1) that picks up lightning arrester leakance and over-voltage breakdown electric current, be connected with the testing circuit output terminal, make the ac amplifier circuit (2) of input signal with detection signal, be connected with the ac amplifier circuit output terminal, make the linear rectification circuit (3) of input signal with its output, the linear rectification circuit output terminal, the one road is connected with dc amplification circuit (4) input end, another road is connected with counting circuit (5) input end, the output of dc amplification circuit (4) connects reometer, and power supply (9) and housing (11).

According to the described lightning arrester performance monitor of claim 1, it is characterized in that 2, described signal deteching circuit (1) is by ring-shaped core M, secondary coil n2 and the arrester ground lead-in wire n1 that passes ring-shaped core constitute on it; Ac amplifier circuit (2), the feedback resistance R2 that is connected with inverting input by difference direct current amplifier K1 and output terminal thereof constitutes; Linear rectification circuit (3), the feeder line G that is connected with the direct current amplifier inverting input by difference direct current amplifier K2, the diode D1 that is connected with its output terminal, diode cathode, and diode output and ground between the capacitor C 1 that is connected constitute; Dc amplification circuit (4), the feedback network that is connected with inverting input by difference direct current amplifier K3 and output terminal thereof constitutes.

According to claim 1 or 2 described lightning arrester performance monitors, it is characterized in that 3, the feedback network of described dc amplification circuit (4) is connected with resistance R 4 with the diode parallel connection by resistance R 5 again and constituted; Described counting circuit (5), comprise by direct current amplifier K4 and the divider resistance R8 that inserts inverting input, the comparer (6) that R9 constitutes, be connected with comparator output terminal, make the pulsqe distributor (7) of clock signal, the driving circuit (8) and the display device that are connected successively with the pulsqe distributor output terminal with comparer output square wave.