Summary of the invention
The purpose of this utility model is the deficiency that overcomes on the prior art, proposes new localization method, and a kind of locating device at one-phase earthing failure in electric distribution network is provided.The localization of faults quickly and accurately of this locating device, and be applicable to metallic earthing, through arcing ground, through various faults situations such as transition resistance eutral groundings.
The technical solution of the utility model is as follows:
A kind of single-phase earth fault positioning device for electrical power distribution network, this single-phase earth fault positioning device is made up of high-voltage signal source and two parts of signal detector, described high-voltage signal source comprises voltage inverter, constant current source, transformer, rectifier bridge, voltage inverter, constant current source, transformer, four parts of rectifier bridge connect in turn, described voltage inverter is an alternating voltage with vehicle-mounted DC voltage inversion, this alternating voltage is successively by constant current source and transformer, output terminal at transformer obtains the constant ac high-voltage signal of an output current, described transformer output terminal also is connected to described rectifier bridge by switchgear, the high direct voltage signal of rectifier bridge output behind overcommutation, by converting switch device, described high-voltage signal source selects to draw ac high-voltage signal and high direct voltage signal;
Described signal detector comprises DC detector and ac detector, described DC detector is made up of Hall DC detector, blue teeth wireless transmitter and blue teeth wireless receiver, the Hall DC detector has pincers type opening, be used to overlap link, utilize Hall effect that direct current signal is detected, the Hall DC detector is connected with the blue teeth wireless transmitter, and blue teeth wireless receiver and transmitter are by wireless connections, and receiver is shown to the result on the liquid crystal; Ac detector is made up of ac magnetic field inductor and signal Processing display device, the ac magnetic field inductor is used to detect AC signal, utilize the electromagnetic induction of external electromagnetic field that AC signal is measured, measurement result is shown on the liquid crystal by the signal Processing display device.
Fault locator of the present utility model realizes localization of fault by following principle:
Localization of fault was divided into for two steps, at first determined fault section, the localization of faults then.Behind the open failure circuit, inject high-voltage dc signal at line fault phase top, according to Kirchhoff's law, direct current signal necessarily constitutes the loop by the trouble spot, circuit top can measure the direct current signal of injection to the path of trouble spot, but not the fault zone can not measure (comprising after non-fault branch and the trouble spot) direct current signal of injection.Road therefore along the line is detected the direct current signal that each affluent-dividing is crossed at crucial take-off point place with signal detector, can detect direct current signal if find a certain branch, the downstream of trouble spot in this branch is described, if detect less than direct current signal, the trouble spot is described in the upstream, section until localization of faults place.
When definite fault section in the 1000m scope with after interior, inject high-voltage AC signal at line fault phase top because line length is shorter in the section, so the capacitance current influence is very little, the amplitude variation more than 5 times will appear in the AC signal before and after the trouble spot.AC signal is detected with signal detector in road along the line, can determine the accurate position of fault.
Advantage of the present utility model is as follows:
1, accurate position that can the localization of faults.
2, be not subjected to the influence of line distribution capacitance, can effectively solve the orientation problem under the high resistance ground situation.
3, not be used in erecting device on every circuit, utilize a covering device can carry out the location of many circuits, save cost greatly.
4, high-voltage signal source adopts the vehicle power power supply, and signal detector adopts hand held structures, utilizes powered battery, is convenient to field operation, the dirigibility height.
5, adopt high-voltage signal source, can guarantee to puncture earth fault, make fault recurrence; Adopt the 60Hz AC signal, can guarantee not to be subjected to the interference of power frequency component, improve measuring accuracy.
6, technology maturation, reliability height are applicable to 3~60kV power distribution network, are applicable to metallic earthing, through arcing ground, through various faults situations such as transition resistance eutral groundings.
Embodiment
, the technical solution of the utility model is described in further detail as figure below in conjunction with instructions by specific embodiment.
A kind of new localization method that the utility model proposes, its principle are to determine section, the localization of faults then earlier.Behind the open failure circuit, fault is injected high-voltage dc signal mutually at circuit top, and road along the line is detected the direct current signal that each affluent-dividing is crossed at crucial take-off point place with signal detector, according to the section at the variation localization of faults place of direct current signal.When fault section during less than 1000m, fault is injected high-voltage AC signal mutually at circuit top, and AC signal is detected with signal detector in road along the line, determines the accurate position of fault.This method belongs to initiative.
Locating device based on the utility model development is made up of high-voltage signal source and two parts of signal detector.Described high-voltage signal source is made up of voltage inverter, constant current source, transformer, rectifier bridge, four parts connect in turn, the external vehicle power of voltage inverter, can be alternating voltage with vehicle-mounted DC voltage inversion, this alternating voltage raises to High AC voltage by constant current source and transformer and guarantees that the output current amplitude is constant, and rectifier bridge is DC voltage, electric current with alternating voltage, current commutates.High-voltage signal source is externally drawn four HV Terminal, draws high-voltage AC signal and high-voltage dc signal respectively, and selects direct current or exchange output by change-over switch.
Described signal detector is divided into DC detector and ac detector, DC detector is made up of Hall DC detector, blue teeth wireless transmitter and blue teeth wireless receiver, and ac detector is made up of ac magnetic field inductor and signal Processing demonstration link.The Hall DC detector has pincers type opening, be used to overlap link, utilize Hall effect that direct current signal is detected, the Hall DC detector is connected with the blue teeth wireless transmitter, blue teeth wireless receiver and transmitter carry out reliable wireless connections in the 10m scope, receiver is shown to the result on the liquid crystal.The ac magnetic field inductor is used to detect AC signal, can utilize the electromagnetic induction of external electromagnetic field that AC signal is measured in the 10m scope, and measurement result is shown on the liquid crystal.Signal detector adopts hand held structures, utilizes powered battery.
Localization of fault was divided into for two steps, at first determined fault section, the localization of faults then.Behind the open failure circuit, inject high-voltage dc signal at line fault phase top, according to Kirchhoff's law, direct current signal necessarily constitutes the loop by the trouble spot, circuit top can measure the direct current signal of injection to the path of trouble spot, but not the fault zone can not measure (comprising after non-fault branch and the trouble spot) direct current signal of injection.Road therefore along the line is detected the direct current signal that each affluent-dividing is crossed at crucial take-off point place with signal detector, can detect direct current signal if find a certain branch, the downstream of trouble spot in this branch is described, if detect less than direct current signal, the trouble spot is described in the upstream, section until localization of faults place.
When definite fault section in the 1000m scope with after interior, inject high-voltage AC signal at line fault phase top because line length is shorter in the section, so the capacitance current influence is very little, the amplitude variation more than 5 times will appear in the AC signal before and after the trouble spot.AC signal is detected with signal detector in road along the line, can determine the accurate position of fault.
As shown in Figure 1, locating device is made up of high-voltage signal source and two parts of signal detector, open failure circuit after the generation earth fault, the lead-out terminal one of high-voltage signal source is terminated at circuit top fault to be gone up mutually, the other end is connected on the earth, adjusts change-over switch and selects direct current output or exchange output.Utilize fault detector road along the line that direct current signal or AC signal are detected, finally find position of failure point.
The high-voltage signal source principle is made up of voltage inverter, constant current source, transformer, rectifier bridge as shown in Figure 2, and four parts connect in turn.R represents voltage inverter, externally draws input port R1+, a R1-, be connected on during use on the both positive and negative polarity of vehicle-mounted 12V power supply, and can be the alternating voltage of 220V, 60Hz with the inversion of vehicle-mounted 12V DC voltage; Z represents constant current source, and electric current that can the control transformer low-pressure side is constant 3A, thereby the electric current that guarantees the transformer high-voltage side is constant 200mA; T represents the double winding step-up transformer, and no-load voltage ratio is 1: 14, original edge voltage can be raise to be the alternating voltage of 3000V, 60Hz; D represents the high-voltage rectifying bridge, can be DC voltage, electric current with alternating voltage, current commutates.High-voltage signal source is externally drawn two high-voltage output end mouths, and wherein K1+, K1-represent to draw high-voltage AC signal, and K2+, K2-represent to draw high-voltage dc signal, by the type of change-over switch K control output signal.
The constant current source principle as shown in Figure 3.The ac voltage output mouth of the external inverter R of input port AN, current transformer is used to measure the current in loop amplitude, x1 is connected with CPU as the secondary side of current transformer with x2, CPU detects the electric current in loop and trigger pulse G1, G2 by driving circuit control controllable silicon K1, K2, constitutes close-loop feedback control.When current in loop was lower than setting value, trigger pulse reduces the silicon controlled conduction angle increased loop current; When current in loop was higher than setting value, trigger pulse increases the silicon controlled conduction angle reduced loop current, has guaranteed the steady current of loop current for setting like this.
The circuit diagram of rectifier bridge as shown in Figure 4.High AC voltage after U2, i2 represent to boost, electric current, VT1, VT2, VT3, VT4 are represented four high-voltage diodes, and C represents flat wave capacitor, and R represents load.VT1 and the VT4 brachium pontis that partners, bearing voltage U 2 at the positive half cycle of U2 is conducting, turn-offs when the U2 zero passage.VT2 and VT3 form another to brachium pontis, and bearing voltage-U2 at the U2 negative half period is conducting, turn-off when the U2 zero passage.Capacitor C plays flat ripple effect, and when voltage U 2 was higher than voltage on the capacitor C, voltage U 2 was powered to load R to the electric capacity charging simultaneously; And when voltage U 2 was lower than voltage on the capacitor C, capacitor C was powered to load R.Therefore rectifier bridge can guarantee provide DC voltage, electric current to load when the input sinusoidal voltage, and guarantees that by flat wave capacitor DC voltage, current amplitude are constant.
The direct current signal detector concept is shown in Fig. 5 A-5C, and detecting device comprises Hall DC detector, blue teeth wireless transmitter and blue teeth wireless receiver.Fig. 5 A is the Hall DC detector, and there is pincers type opening in its edge, is used to overlap link, and pincers type open interior embeds Hall element, can utilize Hall effect that direct current signal is detected.Fig. 5 B is sampling processing circuit and blue teeth wireless transmitter, can amplify detection signal, Filtering Processing, and signal is carried out the AD conversion be transferred to the blue teeth wireless transmitter.Wherein 8051F310 is a central processing unit, and CA3140 is an operational amplifier, and CRM2400 is a bluetooth radio module.Fig. 5 C is the blue teeth wireless receiver, can received signal and the result is shown on the liquid crystal.Wherein 8051F310 is a central processing unit, and CA3140 is an operational amplifier, and CRM2400 is a bluetooth radio module, and LCM046 is a LCD MODULE.After circuit injects direct current signal, need step on bar on the line with the socket of detecting device pincers type mouth, the blue teeth wireless transmitter below circuit can show measurement result automatically.
Alternating current signal detection device principle as shown in Figure 6, the alternating current signal detection device shows that by ac magnetic field inductor and signal Processing link constitutes.When the injection signal is the 60Hz AC signal, can produce the 60Hz alternating electromagnetic field at the circuit surrounding space.The ac magnetic field inductor is the inductive coil of a multiturn number, and the external electromagnetic field signal can induce ac voltage signal in the 10m scope on inductor, and this voltage magnitude is directly proportional with current amplitude on the circuit.After the amplification of induced voltage signal process, the Filtering Processing, the result is shown on the liquid crystal.LF347 is an operational amplifier, is used for the 60Hz ac voltage signal of sensing is amplified, and is convenient to measure.LM317 is a stabilivolt, is used to guarantee the battery supply steady operation.UAF42 is a wave filter, is used for the filtering interfering noise signal, extracts useful 60Hz AC signal.After circuit injects the 60Hz AC signal, below circuit, just can detect and show measurement result automatically signal.