CN201045627Y

CN201045627Y - Intelligent power line fault indicator

Info

Publication number: CN201045627Y
Application number: CNU200720143479XU
Authority: CN
Inventors: 王廷严
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-09
Filing date: 2007-04-09
Publication date: 2008-04-09
Anticipated expiration: 2017-04-09

Abstract

An intelligent electric power line fault indicator of the utility model is used for detecting the short circuit and ground faults of the electric power line, which comprises a short circuit detecting circuit comprising an open current transformer, a bridge rectifying circuit, a low-pass filtering circuit and a historical current peaks holding and comparing circuit, a peak sequence comparing and braking circuit, a power-supplying direction detecting circuit comprising a zero-cross detecting circuit, a pulse shaping circuit and a counting circuit, a ground pulse detecting circuit comprising a band-pass circuit and a phase comparing circuit, and a central core logic processing unit comprising a micro power-consuming single chip microcomputer as the core. The utility model is mainly used to solve the problems that the false action is caused by the inverted transmission of the line when the fault indicator detects the short circuit, and the ground fault detection is not suitable for the loop-network power supply line.

Description

The intelligent electric power line-failure indicator

Technical field:

The utility model relates to a kind of feeder line fault indicating device, especially a kind of electric power line fault indicator.

Background technology:

Line-failure indicator is a kind ofly to be installed on the overhead transmission line, on power cable and the switch cubicle bus row, to be used to indicate the device of fault loop.In case power circuit is short-circuited, the track walker can show by the red alarm on the indicator, determines fault section, branch rapidly, reaches the trouble spot.Thoroughly change blindly hunting in the past, the primitive method that segmentation is closed a floodgate and searched fault section.The subject matter of electric power line fault indicator existence at present has:

1, increasing of power cable makes that the distributed capacitance of cable produced the capacitor discharge pulse to the trouble spot when short trouble took place on the circuit, and the amplitude of this pulse is often very high, easily causes indicator generation misoperation.

2, system loading often has a large amount of motor, and when line failure, these motor are because the load action of inertia, becomes generator and send electricity in trouble spot or system, also can cause fault detector generation misoperation.

3, detection of ground faults generally adopts first half-wave method at present, promptly the sample first half-wave of capacitance current and the ground connection voltage head half-wave of moment of ground connection moment, compare its phase place, when the capacitance current sudden change of sampling ground connection moment and greater than certain numerical value, and with the ground connection same phase time of the first half-wave of voltage of moment, then think earth fault has taken place, this method needs fault detector that (as towards transformer station's direction) is installed according to a certain direction, otherwise indicator can not correct operation, but in distribution line, because power supply capacity, the reason of load variations or optimization load, the action that can fall to load continually, after load had been fallen, supplier of electricity originally changed to meeting, causing originally installing correct fault detector can not correctly work, and therefore this fault detector is available hardly in practice.

Therefore, at many imperfection problems that present fault detector exists, the utility model provides a kind of intelligent electric power line-failure indicator.

Summary of the invention:

The purpose of this utility model provides a kind of intelligent electric power line-failure indicator, is not suitable for a series of problems such as ring network power supply circuit to solve malfunction and the Earth Fault Detection of sending electricity to cause owing to circuit when the short trouble that exists in the present fault detector detects.

The technical scheme that its technical matters that solves the utility model adopts is: this fault detector detects loop, peak value by short-circuit current, and comparator circuit, supplier of electricity are formed to testing circuit, ground connection pulse-detecting circuit and core control circuit in proper order, it is characterized in that: short-circuit current detection loop, peak value order comparator circuit, supplier of electricity are electrically connected with core control circuit respectively to testing circuit, ground connection pulse-detecting circuit, are comprehensively judged and the indication fault circuit by core control circuit.

Principle of work of the present utility model: in the short-circuit detecting circuit that opening current transformer, bridge rectifier, low-pass filtering, historical current peak keep and comparator circuit constitutes, rectification and low-pass filtering are in order to eliminate high frequency interference, the setting value that is used as short-circuit current preserved former peak value by historical current peak retainer, prepare to compare, thereby detect short-circuit current with next detected value.When detecting short-circuit current, peak value in proper order relatively braking circuit begins one by one the relatively size of the adjacent peak value of this fault current, if the size of adjacent peak value is more approaching, then think real fault current, thereby confirmed short trouble, and provided alerting signal, if the reducing gradually of adjacent peak value via the central core Logical processing unit, then think the short circuit pulse electric current that send electricity to cause, the central core Logical processing unit then can not provide alerting signal.The zero cross detection circuit of supplier of electricity in testing circuit becomes the sine wave of electric current and voltage into trapezoidal wave respectively, shaping pulse is carried out shaping to this trapezoidal wave, make it become square wave, two square waves trigger the phase count unit respectively and count, and the value and the setting value of counter compared, thereby judge supplier of electricity to.The ground connection pulse-detecting circuit that is made of bandpass filtering, phase-comparison circuit then is used to judge whether to take place singlephase earth fault, and the central core Logical processing unit is comprehensively judged and carried out the fault loop indication by corresponding command sending unit and display circuit.

Compared with prior art, the beneficial effects of the utility model are can solve malfunction and the Earth Fault Detection of sending electricity to cause owing to circuit when the short trouble that exists in the present fault detector detects to be not suitable for a series of problems such as ring network power supply circuit.

Description of drawings:

Fig. 1 is a structural representation of the present utility model

Fig. 2 is a theory diagram of the present utility model

Fig. 3 is a short-circuit current fault detect loop diagram of the present utility model

Fig. 4 is an in proper order relatively brake-circuit diagram of peak value of the present utility model

Fig. 5 is that supplier of electricity of the present utility model is to detecting loop diagram

Fig. 6 is a ground connection pulse detection loop diagram of the present utility model

Fig. 7 is a ground connection pulse detection loop filter Parameter Map of the present utility model

1 opening current transformer (CT), 2 electric field signal picking up board, 3 signal-processing boards, 4 stepper motors

Embodiment:

Below in conjunction with accompanying drawing the utility model intelligent electric power line-failure indicator is described further:

As shown in Figure 1: current signal of the present utility model is taken from the open C T (1) that is stuck on the lead, constitutes by permeability magnetic material with around thereon coil, and it can being converted to voltage signal and handling for following logical circuit the current signal linear on the line of electric force.Electric field signal picking up board (2) is made of metallic conductor and grading ring, and it is in the formed electric field of high-voltage conducting wires, has the alternation potential between it and the lead, utilizes it to pick up the electric field signal proportional with wire voltage.Signal-processing board (3) is handled judgement to electric current and electric field signal, convert thereof into corresponding logical signal and be connected to central core logical process control module and carry out comprehensive judgment processing, stepper motor (4) is made of the rotor of two groups of coils and a permanent magnet, the failure identification board is installed on the rotor of permanent magnet, two groups of coils are respectively and show coil and involution coil, when pointer detection when having fault to take place, drive to show coil with the poles attract of permanent magnet near self, cause it to be in alarm condition, when timing time then, drive the involution coil motion, near the involution coil, make indicator be in the involution state poles attract of permanent magnet.

Shown in Fig. 2,3,4: short-circuit current detects the loop and is made of open C T, bridge rectifier, low-pass filtering, peak value comparison loop.Bridge rectifier is finished by the B1 among Fig. 3, and it becomes the simple sinusoidal alternating current signal into the direct current signal of pulsation, and some high frequency interference on the low-pass filtering loop filtering circuit of forming through R1 and C1 are given peak holding circuit and peak value comparator circuit with signal.Peak holding circuit is made up of U1, C2 and A1, and core processing unit was gathered the circuit peak value every the regular hour, is stored among the C2, utilizes A1 to carry out impedance conversion, outputs signal to A2 and carries out peakedness ratio, has judged whether short circuit pulse.Stabilivolt D1, R3 and R2 constitute current potential translation bleeder circuit, it makes input signal just can compare greater than the signal of the character voltage of D1, R3 and R2 carry out dividing potential drop to signal, could produce pulse signal when making pulse current greater than the load current certain numerical value.Load current is less than peak value sustaining voltage Uh* (R2+R3)/R2+VD1 at ordinary times, so comparer output high level, and when short trouble took place, electric current increased suddenly, and during greater than above-mentioned numerical value, the comparer output low level, thus the short circuit pulse signal provided.But whether this signal is real short circuit pulse, also will see the in proper order relatively result of braking circuit of peak value.As shown in Figure 4, U2 and C3 form the peak holding circuit in n-1 cycle, U3 and C4 form the peak holding circuit in n cycle, the zero cross signal that the central core Logical processing unit produces according to voltage signal and the timing circuit of inside are controlled U2 and the U3 maintenance of sampling respectively by RC2 and RC3 near current peak, utilize the switching slot of RC2 and RC3 to compare, thereby judge that short circuit pulse is a real short circuit pulse or because the pulse of sending electricity to cause, if send, then locking shows, remove the short circuit pulse sign, thereby effectively prevent the malfunction problem of sending non-failure factors such as electricity to cause, otherwise be judged as real short trouble, trigger the board turning circuit and show.

As shown in Figure 5: supplier of electricity R4, R5, D2, D3, A5 and A6 in testing circuit form zero cross detection circuit; wherein D2 and D3 are used for the input end of guard amplifier to exempt from the destruction of negative voltage; when input voltage greater than zero the time; amplifier output high level is through giving subordinate's processing of circuit after U6 and the U7 shaping.C5, C6, CRY and U4 form the clock reference circuit, produce the 1MHz reference clock, through giving U5 behind 16 frequency divisions as 10 counting clocks.When the current over-zero phase place, the counter of U5 is carried out zero clearing, this moment, U5 was since 0 counting, when voltage over zero arrives, the central control processor application is interrupted, and central control processor judges after the count value of counter is read internal memory, thus determine supplier of electricity to.

As shown in Figure 6, two bandpass filter are extracted the current impulse that produces when earth fault takes place and potential pulse respectively and its RB1 and two of RB2 that gives the central core Logical processing unit are respectively interrupted the application input end, the direction of tide that engages circuit is handled, and whether has sent out singlephase earth fault thereby judge.The frequency characteristic of wave filter as shown in Figure 7, centre frequency is chosen as 5kHz, bandwidth is 500Hz.

Finally, judge and the indication fault circuit by the comprehensive above-mentioned multiline message of central core Logical processing unit.

Claims

1. intelligent electric power line-failure indicator, this fault detector detects loop, peak value by short-circuit current, and comparator circuit, supplier of electricity are formed to testing circuit, ground connection pulse-detecting circuit and central core Logical processing unit in proper order, it is characterized in that: short-circuit current detection loop, peak value order comparator circuit, supplier of electricity are electrically connected with the central core Logical processing unit respectively to testing circuit, ground connection pulse-detecting circuit, and are comprehensively judged and indication fault by the central core Logical processing unit.

2. intelligent electric power line-failure indicator as claimed in claim 1 is characterized in that: short-circuit current detection loop keeps loop and peak value comparison loop to be electrically connected in proper order by opening current transformer loop, bridge rectifier loop, low-pass filtering loop, historical peak value and constitutes.

3. intelligent electric power line-failure indicator as claimed in claim 1, it is characterized in that: the output signal that short-circuit current detects the loop inserts peak value order comparator circuit, peak value in proper order relatively braking circuit is judged the waveform of short-circuit current, when being judged as the short circuit waveform, core control circuit provides alerting signal, is judged as short trouble; When judging that waveform belongs to when sending electricity, core control circuit does not trigger warning circuit, thereby avoids the erroneous judgement of sending electricity to cause.

4. intelligent electric power line-failure indicator as claimed in claim 1 is characterized in that: supplier of electricity to testing circuit in order to judge supplier of electricity to, be electrically connected to form in proper order by zero passage detection loop, shaping pulse loop and counter loop.

5. intelligent electric power line-failure indicator as claimed in claim 1 is characterized in that: the ground connection pulse-detecting circuit is in order to judge whether to take place singlephase earth fault, and by the bandpass filtering loop, pulse differentiates that loop and phase place comparison loop constitute.

6. intelligent electric power line-failure indicator as claimed in claim 1 is characterized in that: the central core Logical processing unit is made of ultra low-power microcontroller, fill order transmitting element and display circuit.