CN2293077Y

CN2293077Y - Selective earthing line device for power distribution network

Info

Publication number: CN2293077Y
Application number: CN 96204431
Authority: CN
Inventors: 耿齐国
Original assignee: LINGYI COUNTY POWER ADMINISTRATION SHANXI PROV
Current assignee: LINGYI COUNTY POWER ADMINISTRATION SHANXI PROV
Priority date: 1996-02-12
Filing date: 1996-02-12
Publication date: 1998-09-30
Anticipated expiration: 2006-02-12

Abstract

The utility model relates to a selective earthing line device for a power distribution network. The utility model is composed of a zero-sequence current transformer 1, a control cable 2, a selective earthing line disk 23, etc. The utility model is suitable for the power distribution network which has three-phase alternating current, and the neutral point of the power distribution network is not connected with the earth. If the single-phase earthing fault is generated in operation of the power distribution network, by using the utility model, the zero sequence current of each line can be displayed, the secondary voltage value of the earthing can be displayed, the light word brand and the sound of the earthing can be displayed, and the earthing time can be metered; a watcher of a power plant or a transformer substation can clearly know the earthing condition of an electric network, and the earthing line can be safely, conveniently, quickly and accurately selected; thereby, the switching-off times of the line can be reduced to the minimal degree, and the power failure of a user can be avoided when the user does not use the earthing line.

Description

Power distribution network is selected the ground path device

The power distribution network that the utility model power distribution network selects the ground path device to relate to three-phase alternating current, isolated neutral is in operation and selects to take place the device of singlephase earth fault circuit.

At present the three-phase alternating current of China, the power distribution network of isolated neutral are in operation when singlephase earth fault takes place, and the operator on duty of generating plant or transformer station generally adopts line-by-line the method for drawing, closing a floodgate when short out to select ground path.Its shortcoming one is to select slowly; The 2nd, make unearthed line user suffer the loss of power failure; The 3rd, increased the number of times of operating a switch.Yan Zhi some are injected the device such as the JDT type (seeing " electrification of the countryside " 1992 the 4th phases) of marking current such as TY-01 type (seeing the 7th phase of " electrification of the countryside " nineteen ninety-five) or detection ground connection harmonic wave to power distribution network when ground connection in recent years, all must be when electrical network generation single-phase earthing, by person on duty's hand-held detector, circuit is surveyed the selection ground path one by one, so both dangerous also inconvenient, when meeting the power distribution network intermittent earth, more be difficult to select quickly and accurately ground path.

When the purpose of this utility model is in operation the generation distribution circuit single-phase earth fault with regard to the power distribution network for three-phase alternating current, isolated neutral, the person on duty of generating plant or transformer station utilizes the utility model can more clearly understand electrical network ground connection situation, can safety, select ground path easily and fast, exactly, can minimize and avoid power failure to the circuit number of times of operating a switch to unearthed line user.

The purpose of this utility model realizes by following technical proposals: the utility model is by zero sequence current mutual inductor 1, umbilical cable 2, select ground path dish 23 compositions such as grade, it is characterized in that: on the bus of the power distribution network of a three-phase alternating current, isolated neutral, each distribution line head end is all installed zero sequence current mutual inductor 1, each zero-sequence current table 3 or 3 on umbilical cable 2 and selection ground path dish 23 of its secondary circuit ' be connected; Ground voltage table 5, ground connection alarm window 7, ground connection sounder switch 15 also are installed in ground connection sounder 19, grounding relay 12, fuse 4 and select to be connected with the open delta secondary coil loop of distribution bus voltage transformer (VT) on the ground path dish 23; Ground connection timer 22 is connected with supply 20 through the normally opened contact 21 of grounding relay 12, all is installed in to select on the ground path dish 23.The model of the zero sequence current mutual inductor that the utility model is all should be consistent, and the model of all zero-sequence current tables, range are all the same.The zero-sequence current of normal each distribution line in service of power distribution network all is zero, the open delta secondary coil loop no-voltage of distribution bus voltage transformer (VT), ground connection alarm window 7 does not work, and ground connection sounder 19 is noiseless, grounding relay 12 is inoperative, and ground connection timer 22 does not show.When single-phase dead ground fault takes place in power distribution network, voltage then appears in the open delta secondary coil loop of distribution bus voltage transformer (VT), by about ground voltage table 5 indication 100V (partial earth voltage is lower), so make ground connection alarm window 7 show bright, ground connection sounder 19 is presented is furnished with the musical sound that ground connection is handled the lyrics, grounding relay 12 starting, its contact 21 closures, connect ground connection timer 22 loops begin to measure ground connection second, branch, the time.If singlephase earth fault occurs on the distribution line, the zero-sequence current of distribution line that singlephase earth fault then takes place is all big than the zero-sequence current of All other routes, and its value is greater than the summation of each unearthed circuit zero-sequence current, because the model unanimity that each circuit zero sequence current mutual inductor is selected for use, the model that the zero-sequence current table is selected for use, range are all the same, and install concentratedly on a dish, so the person on duty of generating plant or transformer station can more clearly understand electrical network ground connection situation, can select ground path safely, easily and fast, exactly.Obvious faults such as general distribution circuit single-phase earth fault pilosity is born in broken string, is bumped tree, magnetic bottle punctures, foreign object contact wire, eliminating is found with interior in two hours of can move in regulation single-phase earthing permission continuation.Reach two hours as the 22 metering times of ground connection timer and when not getting rid of fault or having only power failure to handle, just stopped this circuit electricity consumption.So just the circuit number of times of operating a switch is minimized and has avoided power failure to unearthed line user.The utility model those of ordinary skill is easy to realize.

The three-phase alternating current of present China, the power distribution network of isolated neutral, it is in service when singlephase earth fault takes place, the person on duty of generating plant or transformer station is general to adopt by the ground connection method that the order line-by-line draws, closes a floodgate when short out of operating a switch and selects ground path, make the user that earth fault line does not take place like this, all to suffer the loss of power failure, and select to have increased the number of times of operating a switch slowly.The method of when ground connection, injecting marking current or surveying harmonic current of development in recent years to power distribution network all must by person on duty's hand-held detector one by one circuit survey the selection ground path, so both dangerous, also inconvenient, more be difficult to select quickly and accurately ground path when meeting the power distribution network intermittent earth.And behind employing the utility model, when power distribution network generation singlephase earth fault, the ground connection alarm window appears, the ground connection sound equipment appears, begin to measure the ground connection time, the ground voltage table can reflect the degree of ground connection, the person on duty of generating plant or transformer station can more clearly understand electrical network ground connection situation, maximum and according to the ground path zero-sequence current greater than these characteristics of summation of unearthed each circuit zero-sequence current, can select the distribution line that singlephase earth fault takes place safely, easily and fast, exactly, notify this circuit to be responsible for handling into inspection.When only in two hours of regulation permission continuation operation, not getting rid of earth fault or having only power failure to handle, just stop this circuit electricity consumption.So just the circuit number of times of operating a switch is minimized and has avoided power failure to unearthed line user.

The drawing of accompanying drawing is described as follows:

Accompanying drawing 1 is a zero sequence current mutual inductor electric hookup of the present utility model.Diagram 1 is for to be installed in a zero sequence current mutual inductor in the distribution outlet, and 2 is this secondary circuit umbilical cable, and 3 is the zero-sequence current table of this circuit.

Accompanying drawing 2 is voltage circuit electric hookups of the present utility model.Diagram 4 is for being connected to the fuse in distribution bus voltage transformer (VT) open delta secondary coil loop, 5 is the ground voltage table, 6 is commutation diode, and 7 is the light emitting diode of ground connection alarm window, and 8 is resistor, 9 is commutation diode, 10 is resistor, and 11 is capacitor, and 12 is grounding relay, 13 is commutation diode, 14 is resistor, and 15 is ground connection sounder switch, and 16 is capacitor, 17 is audio manifold block, 18 is triode, and 19 is the ground connection sounder, and 20 is supply, 21 is the grounding relay normally opened contact, and 22 is the ground connection timer.

Accompanying drawing 3 is the synoptic diagram that the utility model is connected with power distribution network.Diagram 1 is for to be installed in a zero sequence current mutual inductor in the distribution outlet, and 2 is umbilical cable, and 3 is the earth current meter of this distribution line, 3 ' be the zero-sequence current table of other each bar distribution lines; 5 is the ground voltage table, and 7 is the ground connection alarm window, and 15 is ground connection sounder switch, and 19 is the ground connection sounder, and 22 is the ground connection timer, and 23 for installing the selection ground path dish of above-mentioned 3-22 parts.Accompanying drawing 3 can explain the accompanying drawing of book extract.

Below in conjunction with accompanying drawing the realization preferred embodiment of the utility model is described further:

Power distribution network is normally in service, three-phase voltage equilibrium vector and be zero, no residual voltage, the open delta secondary coil loop no-voltage of distribution bus voltage transformer (VT) selects the ground voltage table 5 on the ground path dish 23 to be designated as zero, ground connection alarm window 7 does not work, ground connection sounder 19 voiceless sounds, ground connection timer 22 do not show that the three-phase current sum of each distribution line also is zero simultaneously, zero sequence current mutual inductor 1 no current passes through, the zero-sequence current table 3 and 3 that its secondary connects ' also be designated as zero.When single-phase dead ground fault takes place in power distribution network, residual voltage appears in distribution bus voltage transformer (VT) open delta secondary coil loop, and this voltage is powered through fuse 4: be installed in about the ground voltage table 5 indication secondary voltage ratings 100V that selects on the ground path dish 23 (partial earth voltage is lower); It is bright that ground connection alarm window 7 shows after commutation diode 6 rectifications, resistor 8 current limlitings; By commutation diode 13 rectifications, resistor 14 current limlitings, through ground connection Stereo Switch 15, capacitor 16 filtering, audio manifold block 17 programmings are played out ground connection sounder 19 after triode 18 amplifies and are furnished with the musical sound that earth fault is handled the lyrics; Grounding relay 12 is by commutation diode 9 power supply, start after resistor 10 current limlitings, capacitor 11 filtering, closed its contact 21, supply 20 make ground connection timer 22 show and begin to measure ground connection second, branch, the time.Take place simultaneously in the zero sequence current mutual inductor 1 of earth fault line by the ground current value of full electric network, the zero-sequence current table 3 that its secondary is connected through umbilical cable 2 is also indicated two sub-values of the whole network ground current; And the circuit of earth fault does not take place, only pass through this circuit zero sequence out-of-balance current in its zero-sequence transformer, be presented at zero-sequence current table 3 ' in, the indicated value of the zero-sequence current table of ground path is maximum and greater than the summation of the zero-sequence current table indicated value of other unearthed circuits, because the zero sequence current mutual inductor model unanimity that each circuit of power distribution network is installed, characteristic is the same, the model of zero-sequence current table, range is all the same, and install concentratedly and selecting on the ground path dish 23, so the person on duty of generating plant or transformer station can more clearly understand electrical network ground connection situation, energy safety, convenient, fast, select the circuit that earth fault takes place exactly.When allowing to continue not investigate and prosecute in 2 hours working times the maybe necessary power failure ability of earth fault handling failure in accordance with regulations as single-phase earthing, just must cut off this distribution line electricity consumption, so just the circuit number of times of operating a switch be minimized and avoided power failure to unearthed line user.

Claims

1, the power distribution network of a kind of three-phase alternating current, isolated neutral selects the ground path device to be made up of zero sequence current mutual inductor (1), umbilical cable (2), selection ground path dish (23) etc., it is characterized in that: on the bus of a power distribution network, the head end of each distribution line is all installed zero sequence current mutual inductor (1), and each is connected its secondary circuit with the zero-sequence current table (3 or 3 ') of selecting ground path dish (23) to go up this circuit through umbilical cable (2); Ground voltage table (5), ground connection alarm window (7), ground connection sounder switch (15) also are installed in ground connection sounder (19), grounding relay (12), fuse (4) and select to be connected with the open delta secondary coil loop of distribution bus voltage transformer (VT) on the ground path dish (23); The normally opened contact (21) of ground connection timer (22) through grounding relay (12) is connected with supply (20) all to be installed in to be selected on the ground path dish (23).

2, power distribution network according to claim 1 is selected the ground path device, and the model of all zero sequence current mutual inductors should be consistent, and the model of all zero-sequence current tables, range are all the same.