CN207882369U - Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument - Google Patents
Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument Download PDFInfo
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- CN207882369U CN207882369U CN201721582971.7U CN201721582971U CN207882369U CN 207882369 U CN207882369 U CN 207882369U CN 201721582971 U CN201721582971 U CN 201721582971U CN 207882369 U CN207882369 U CN 207882369U
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Abstract
The utility model discloses Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument, which includes variable voltage source, adjustable resistance, main power source output loop switch, adjustable resistance switch, by-pass switch and current detector；Variable voltage source is connected with adjustable resistance, forms main power source output loop；Main power source output loop switch is serially connected in main power source output loop, and adjustable resistance switch is serially connected between main power source output loop switch and adjustable resistance；One end of by-pass switch is connected with adjustable resistance switch, and the other end is connected with adjustable resistance switch；Current detector is serially connected in respectively in the branch of main power source output loop and adjustable resistance.This position indicator can be based on electric-resistivity method, shunting searches earth point, various Groundings can effectively be applied to, it is applied widely, so that the lookup of Secondary Circuit of Potential Transformer multipoint earthing, positioning is not influenced by Contact patch, earth point can quickly be searched under any circumstance.
Description
Technical field
The utility model is related to technical field of electric power detection, and in particular to Secondary Circuit of Potential Transformer multipoint earthing is quick
Position indicator and lookup method
Background technology
Regulation, the secondary circuit of voltage transformer is arranged only to allow have one point earth according to counter.But transformer substation voltage mutual inductance
Device common return connection equipment is more, and expanded range is wide, due to artificial wiring error or cable insulation aging etc., occurs frequently in
Multipoint earthing in the common return of one electrical connection.When N600 respectively switch yard ground connection and control room ground connection when, if being
System breaks down, and substation ground network will flow through major break down electric current, and at this moment the both ends N600 will appear potential difference, it will cause neutral point
Voltage-phase offset, while this additional earth potential difference component can cause failure phase protective relay according to dynamic or malfunction
(reversed malfunction or positive surmount).If N600 poor contacts, the voltage-phase offset of neutral point will also result in.South electric network model
A lot of 220kV caused by protective voltage transformer, secondary circuit multipoint earthing and the above false protection thing has occurred in enclosing
Part.South counter arrange of net is distinctly claimed that Secondary Circuit of Potential Transformer has and only one point earth, multipoint earthing currently on the market are looked into
Look for instrument generally using the principle for adding the shunting of low-frequency d signal, but there are two point defects for the principle：
1, shunting requires two ground branch resistance suitable, but on-site actual situations are that intrinsic earth point ground connection is good
Good, resistance is generally in 0.01 ohms, and fault ground point is frequently due to the reasons such as cable core breakage ground connection, there is ground connection
Resistance, generally at 10 ohm or more, 1000 times of difference of them, therefore fault ground point shunts very little, it is difficult to it measures.But it is live
Fault ground point forms voltage difference due to having between induced voltage, and intrinsic earth point in practice, therefore can form electric current.Cause
This on-site actual situations and the difference of principle of instrument cause in the market instrument practicability on sale it is very poor, do not meet live practical need
It wants.
2, instrument is constant-current source, and export control is electric current, but is not limited explicitly voltage, if intrinsic earth point
It is grounded bad, there are 10 ohms resistance, then instrument output voltage is higher, which scurries into ac voltage circuit, deposits
In larger security risk.
Therefore, it there is no at present and adapt to the maturing apparatus of various situations for relay protection personnel use.The prior art has much room for improvement
And development.
Invention content
The purpose of the utility model is to overcome above-mentioned the deficiencies in the prior art, provide a kind of Secondary Circuit of Potential Transformer
Multipoint earthing Quick positioning instrument and lookup method make the lookup of Secondary Circuit of Potential Transformer multipoint earthing, positioning are not grounded
Form influence, earth point can quickly be searched and be improved under any circumstance operational security, to greatest extent reduction connect
It searches the time, reduce the influence to running equipment in place.
To achieve the above object, the technical solution of the utility model is：
Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument, including variable voltage source, adjustable resistance, main power source are defeated
Go out circuit switching, adjustable resistance switch, by-pass switch and current detector；Wherein,
Variable voltage source is connected with adjustable resistance, forms main power source output loop；Main power source output loop switch concatenation
In main power source output loop, adjustable resistance switch is serially connected between main power source output loop switch and adjustable resistance；Bypass is opened
One end of pass is connected with adjustable resistance switch, and the other end is connected with adjustable resistance switch；Current detector is serially connected in respectively
In the branch of main power source output loop and adjustable resistance, with detect respectively main power source output loop size of current and can
Adjust the size of current of the branch of resistance.
The Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument, further includes current-limiting protection circuit, and current limliting is protected
Protection circuit is mutually concatenated with main power source output loop, for protecting main power source output loop.
The Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument further includes capacitance touch operating display, electricity
Hold touch operation display screen respectively with adjustable resistance, main power source output loop switch, adjustable resistance switch, by-pass switch and electricity
Current sensor is connected, and for being operated to main power source output loop switch, adjustable resistance switch and by-pass switch, adjusts
The resistance value of adjustable resistance shows the size of current of main power source output loop and the size of current of adjustable resistance branch.
The main power source output loop switch, adjustable resistance switch, by-pass switch are all made of double-pole single throw.
The adjustable resistance is made of multiple resistance, ranging from 1~399 ohm of resistance adjustment, and minimum scale is 2 ohm.
The voltage range of variable voltage source output is：1~20V, display resolution：1V, error：≤±0.2V；It is defeated
Go out
Current range is：0~200mA.
The detection range of the current detector：0~200mA；Display resolution：0.01mA；Error≤± 0.5mA ±
1%.
Compared with prior art, advantage is the utility model：
1, Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument provided by the utility model can be based on electric-resistivity method, divide
Stream method searches earth point, can effectively apply to various Groundings, applied widely.
2, instrument carries current detector to output current and flows through adjustable resistance electric current and measured in real time, without
External split-core type meter and it can determine whether that there are two points ground faults.
3, man-machine interface is friendly, division switch, regulation resistance, measure the operations such as electric current can in liquid crystal display into
Row, moreover it is possible to which display instrument main electrical scheme grasps field test wiring convenient for technical staff in real time, avoids the wind such as mis-wired maloperation
Danger.
Description of the drawings
Fig. 1 is the electricity for the Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument that the utility model embodiment 1 provides
Road schematic diagram；
Fig. 2 is the circuit diagram that current-limiting protection circuit is serially connected on the basis of Fig. 1；
Fig. 3 a-3c are the circuit diagram of current-limiting protection circuit；
Fig. 4 is the method for the lookup Secondary Circuit of Potential Transformer multipoint earthing that the utility model embodiment 2 and 3 provides
Flow chart；
Fig. 5 is that control room PT secondary circuits N600 is collected the circuit diagram after ground connection connection line accesses Fig. 1.
Specific implementation mode
The content of the utility model is described in further details with reference to the accompanying drawings and detailed description.
Embodiment 1：
As shown in fig.1, for the electricity of Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument provided in this embodiment
Road schematic diagram, the Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument include variable voltage source, adjustable resistance R, main electricity
Source output loop switch K2, adjustable resistance switch K, by-pass switch K and current detector.Specifically, it leads in the present embodiment
Power supply output loop switch K2, adjustable resistance switch K and by-pass switch K are all made of double-pole single throw, i.e., two secondary contacts are simultaneously
Connection, with the switch reliability of raising.
Wherein, which is connected with adjustable resistance, main power source output loop is formed, specifically, in this implementation
In example, the DC voltage range of variable voltage source output is 1~20V, display resolution：1V, error：≤±0.2V；Output
Current range is：0~200mA.The upper voltage limit exported by the way that variable voltage source is arranged, shadow is caused to avoid to operating loop
It rings；Main power source output loop switch is serially connected in main power source output loop, and adjustable resistance switch is serially connected in main power source output loop
Between switch and adjustable resistance；One end of by-pass switch is connected with adjustable resistance switch, and the other end and adjustable resistance switch phase
Connection；Current detector is serially connected in respectively in the branch of main power source output loop and adjustable resistance, to detect main electricity respectively
The size of current of the size of current of source output loop and the branch of adjustable resistance, specifically, the detection range of current detector：
0~200mA；Display resolution：0.01mA；Error≤± 0.5mA ± 1%., current detector passes through standard electric known to acquisition
The voltage drop generated when electric current flows through being hindered, according to Ohm's law, size of current is obtained by can measure.
By so designing, this Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument can be based on electric-resistivity method, shunting
Method searches earth point, can effectively apply to various Groundings, applied widely, keeps Secondary Circuit of Potential Transformer more
Lookup, the positioning of point ground connection are not influenced by Contact patch, and earth point quickly can be searched and be improved under any circumstance
Operational security reduces the earth point lookup time, reduces the influence to running equipment to greatest extent.Meanwhile this instrument charges certainly
Current sensor is to output current and flows through adjustable resistance electric current and is measured in real time, without external split-core type meter and can determine whether
There are two points ground faults.
One kind as the present embodiment is preferred, as shown in Fig. 2, above-mentioned Secondary Circuit of Potential Transformer multipoint earthing is quick
Position indicator further includes current-limiting protection circuit, and current-limiting protection circuit is serially connected in main power source output loop, current-limiting protection circuit pair
The electric current that main power source output loop flows through is limited and (is no more than 200mA) to protect instrument not burnt because of short circuit.Such as Fig. 3 a
Shown, which converts size of current to voltage value first, and (electric current flows through known measuring resistance and is converted into voltage (figure
Middle TX-MASK)), then as shown in Figure 3b, by the voltage value, (corresponding 200mA flows through standard electric resistance value with the voltage value of setting
Voltage drop) input comparator is compared, and comparison result carries out operation as the input of rest-set flip-flop, and the output of rest-set flip-flop
Controlling potential as the relay being concatenated into main power source current supply circuit.As shown in Figure 3c, when main circuit current is more than 200mA
When, relay controlling potential is high level, relay loss of excitation and so that the contact being serially connected in main power circuit is disconnected, to by instrument
Device output disconnects, and achievees the purpose that current-limiting protection, and then ensure the accuracy safe to use and testing result of this instrument.
Preferably, above-mentioned Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument is also for another kind as the present embodiment
Including touch operation display screen, touch operation display screen is opened with adjustable resistance, main power source output loop switch, adjustable resistance respectively
Pass, by-pass switch and current detector are connected, for main power source output loop switch, adjustable resistance to be switched and bypassed
Switch is operated, and the resistance value of adjustable resistance is adjusted, and shows main power source output loop electric current and adjustable resistance branch current.
That is, the operations such as division switch, regulation resistance, measurement electric current can carry out in operating display, meanwhile, the operation is aobvious
Display screen can also display instrument main electrical scheme, grasping field test wiring in real time convenient for technical staff, (test connection is divided into external experiment
Line and closed test line, the black line that external test connection has the red line for connecing positive terminal and connects negative pole end, closed test wiring have master
The division state of power supply output loop switch, adjustable resistance switch, by-pass switch), mis-wired maloperation equivalent risk is avoided, specifically
Ground, in the present embodiment, the operating display are capacitance touch operating display, in order to the operation of technical staff.
Specifically, in the present embodiment, above-mentioned adjustable resistance is made of multiple resistance, 1~399 Europe of resistance adjustment range
Nurse, minimum scale is 2 ohm, can accurately adjust the variation of output voltage, so as to accurately search earth current.
Embodiment 2：
As shown in figure 4, for a kind of stream of method that searching Secondary Circuit of Potential Transformer multipoint earthing provided by the embodiment
Cheng Tu includes the following steps：
S1, as shown in Figure 5, control room PT secondary circuits N600 is collected ground connection connection line, and to access voltage shown in FIG. 1 mutual
In the detection interface of sensor secondary circuit multipoint earthing Quick positioning instrument；Wherein, PT secondary circuits N600 has n items and alignment branch
Road.
S2, judge PT voltage secondary circuits N600 whether one point earth inspection
S201, main power source output loop switch K2 is disconnected, closes by-pass switch K, disconnect ground connection connection line；
S202, the resistance value for adjusting adjustable resistance are 0 ohm, close adjustable resistance switch R, disconnect by-pass switch K, read
The branch current of adjustable resistance R；In the present embodiment, the branch current of adjustable resistance R is 40mA；
S203, by-pass switch K is closed, disconnects adjustable resistance switch K1, the resistance value of adjustable resistance R is increased into 11 Europe
Nurse, to obtain apparent curent change, (specific resistance value is grounded depending on field condition with the ground resistance of another earth point and two
Voltage difference between point is related, if curent change is smaller can suitably to increase or reduce adjustable electric resistance value, is become with obtaining apparent electric current
Turn to principle), adjustable resistance switch K1 is closed, by-pass switch K is disconnected, reads the branch current of adjustable resistance R, at this time adjustable electric
Hinder the branch current 7mA of R；
S204, the branch current of the adjustable resistance of step S202 and S203 is analyzed, electric current changes, then it represents that
There are 2 points or multipoint earthings by PT voltage secondary circuits N600, and enter step S3；
S3, the more a earth points of each branch PT secondary circuits N600 (use electric-resistivity method, without add variable voltage source) are searched, led to
It crosses on the basis of step S1 and S2 after confirming and having two points ground fault, can continue to exclude earth point specifically in which branch with electric-resistivity method
On, following finding step is executed successively：
S301, it disconnects main power source output loop switch K2, close by-pass switch K, the resistance value of adjustment adjustable resistance R is 11
Ohm (for specific resistance value depending on field condition, the voltage difference between the ground resistance of another earth point and two earth points is related, if
Curent change is smaller can suitably to increase or reduce adjustable electric resistance value, to obtain apparent curent change as principle), disconnect ground connection connection
Adjustable resistance switch K1 is closed in wiring；
S302, high-precision clamp ammeter (alternating current shelves) is used to clamp each line branch of PT secondary circuits N600
It is firmly motionless；
S303, by-pass switch K is closed, measures the first electric current I of each line branches of N600, disconnect by-pass switch K, measured
The the second electric current I ' for going out each line branches of N600 compares the first electric current I of each line branch and value I ' of the second electric current, if a certain
The value of the first electric current I and the second electric current I ' of line branch do not change, then it represents that and earth point is not present in the line branch, if certain
The value of the first electric current I and the second electric current I ' of one line branch change, then it represents that there are earth points for the line branch.
Embodiment 3：
The present embodiment is basic and embodiment 2 is identical, the difference is that step S3, in the present embodiment,
S3, the more a earth points (using shunting, variable voltage source must be added) of each branch PT secondary circuits N600 are searched, passed through
Confirm on the basis of step S1 and S2 after having two points ground fault, if indoors due to two earth points, voltage between two earth points
Secondary voltage circuit three-phase load is unbalanced in poor very little, or station, causes N600 to flow through larger out-of-balance current interference and sentences
It is disconnected, it can not continue to exclude earth point specifically on any Tiao Zhi road with electric-resistivity method, then shunting can be used, pass through and adjustable electric is added
Potential source judges earth point.
S301, it closes main power source output loop switch K2, close by-pass switch K, the resistance value of adjustment adjustable resistance R is 11
(resistance of fault ground point is generally between several ohm to hundreds of ohm ohm in live actual motion, and adjustable resistance is set as
11 ohm can form apparent shunting), ground connection connection line is disconnected, adjustable resistance switch R is closed, closes main power source output loop
Switch K2；
S302, each line branch of PT secondary circuits N600 is vised with clamp current detector it is motionless；
S302, by-pass switch is disconnected, setting variable voltage source output voltage is 1V (since adjustable resistance is set as 11 Europe
Nurse, no matter why fault ground point ground resistance is worth, and entire loop resistance will be not more than 11 ohm, and output voltage, which is 1V, to be obtained
Take the electric current not less than 90mA, and the relatively low influence be conducive in reduction search procedure as far as possible to running equipment of output voltage),
The size of current for reading the size of current and adjustable resistance branch of main power source output loop, measures each line branches of N600 successively
Size of current I1、I2、I3……In；
If a certain line branch measures size of current and is not zero, and the sum of the branch current of the line branch current and adjustable resistance
Equal to the electric current of main power source output loop, then judge that there are earth points for the line branch.
Above-described embodiment simply to illustrate that the utility model technical concepts and features, the purpose is to be to allow this field
Interior those of ordinary skill can understand the content of the utility model and implement according to this, can not limit the utility model with this
Protection domain.The equivalent changes or modifications that every essence according to the utility model content is made, should all cover in this reality
With in novel protection domain.
Claims (7)
1. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument, which is characterized in that including variable voltage source, adjustable electric
Resistance, main power source output loop switch, adjustable resistance switch, by-pass switch and current detector；Wherein,
Variable voltage source is connected with adjustable resistance, forms main power source output loop；Main power source output loop switch is serially connected in master
In power supply output loop, adjustable resistance switch is serially connected between main power source output loop switch and adjustable resistance；By-pass switch
One end is connected with adjustable resistance switch, and the other end is connected with adjustable resistance switch；Current detector is serially connected in main electricity respectively
In the branch of source output loop and adjustable resistance, to be respectively used to the detection size of current of main power source output loop and adjustable
The branch current size of resistance.
2. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument as described in claim 1, which is characterized in that further include
Current-limiting protection circuit, current-limiting protection circuit are mutually concatenated with main power source output loop, for protecting main power source output loop.
3. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument as claimed in claim 1 or 2, which is characterized in that also
Including capacitance touch operating display, capacitance touch operating display respectively with adjustable resistance, main power source output loop switch, can
Resistance switch, by-pass switch and current detector is adjusted to be connected, for being switched to main power source output loop switch, adjustable resistance
And by-pass switch is operated, and adjusts the resistance value of adjustable resistance, show main power source output loop size of current and can
Adjust the branch current size of resistance.
4. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument as claimed in claim 1 or 2, which is characterized in that institute
It states main power source output loop switch, adjustable resistance switch, by-pass switch and is all made of double-pole single throw.
5. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument as described in claim 1, which is characterized in that it is described can
Resistance is adjusted to be made of multiple resistance, ranging from 1~399 ohm of resistance adjustment, minimum scale is 2 ohm.
6. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument as described in claim 1, which is characterized in that it is described can
Adjust voltage source output voltage range be：1~20V, display resolution：1V, error：≤±0.2V；The current range of output is：
0~200mA.
7. Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument as described in claim 1, which is characterized in that the electricity
The detection range of current sensor：0~200mA；Display resolution：0.01mA；Error≤± 0.5mA ± 1%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721582971.7U CN207882369U (en) | 2017-11-23 | 2017-11-23 | Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721582971.7U CN207882369U (en) | 2017-11-23 | 2017-11-23 | Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207882369U true CN207882369U (en) | 2018-09-18 |
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ID=63501098
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721582971.7U Active CN207882369U (en) | 2017-11-23 | 2017-11-23 | Secondary Circuit of Potential Transformer multipoint earthing Quick positioning instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207882369U (en) |
-
2017
- 2017-11-23 CN CN201721582971.7U patent/CN207882369U/en active Active
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