CN202649370U - PT (potential transformer) secondary loop multipoint grounding online monitor - Google Patents

PT (potential transformer) secondary loop multipoint grounding online monitor Download PDF

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Publication number
CN202649370U
CN202649370U CN 201220311316 CN201220311316U CN202649370U CN 202649370 U CN202649370 U CN 202649370U CN 201220311316 CN201220311316 CN 201220311316 CN 201220311316 U CN201220311316 U CN 201220311316U CN 202649370 U CN202649370 U CN 202649370U
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CN
China
Prior art keywords
pulpit
secondary circuit
point
lightning arrester
milliammeter
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN 201220311316
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Chinese (zh)
Inventor
王永辉
赵青
刘鹏
郭桐
穆炽玮
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
State Grid Corp of China SGCC
State Grid Hebei Electric Power Co Ltd
Shijiazhuang Power Supply Co Ltd
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Shijiazhuang Power Supply Co Ltd
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Priority to CN 201220311316 priority Critical patent/CN202649370U/en
Application granted granted Critical
Publication of CN202649370U publication Critical patent/CN202649370U/en
Anticipated expiration legal-status Critical
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Abstract

The utility model relates to a PT (potential transformer) secondary loop multipoint grounding online monitor which comprises a control chamber one-point grounding connecting wire (1) of a PT secondary loop, a lightning arrester F, a milliammeter A, a small disconnecting link K and a slide-wire rheostat R. The control chamber one-point grounding connecting wire (1) is connected between a control chamber zero phase N600 of the PT secondary loop and a secondary equipotential ground screen B, the milliammeter A, the small disconnecting link K and the slide-wire rheostat R are sequentially connected in series and then are connected in parallel with the control chamber one-point grounding connecting wire (1), and the lightning arrester F is connected between the control chamber zero phase N600 and the secondary equipotential ground screen B. The PT secondary loop multipoint grounding online monitor has the advantage that the online monitor can accurately judge hidden trouble of multipoint grounding and provide technical support for troubleshooting the hidden trouble of relay protection on the premise of ensuring the running PT secondary loop not to lose grounding points without affecting normal operation of the online monitor.

Description

PT secondary circuit multipoint earthing on-line monitoring instrument
Technical field
The utility model relates to a kind of PT secondary circuit multipoint earthing on-line monitoring instrument.
Background technology
Transformer station has occured a lot of because the example of the protection malfunction that PT secondary circuit multipoint earthing causes at present; the PT secondary circuit multipoint earthing occurs owing to transformer station's reorganization and expansion causes; for such problem; existing LT-N600 PT multipoint earth faults orientator need to add electric signal to the PT secondary circuit; judge with the variation that detects this signal whether the PT secondary circuit multipoint earthing has occured; this electric signal can cause interference to the protection equipment of operation; affect its normal operation, may cause the malfunction and movement resistance of protection equipment.Therefore, need a kind of equipment that the PT secondary circuit does not lose earth point and do not affect the on-line monitoring PT secondary circuit multipoint earthing of the normal operation of protection equipment that can guarantee to move.
The utility model content
Technical problem to be solved in the utility model provides a kind of PT secondary circuit guaranteeing operation and does not lose earth point and do not affect under the prerequisite that protection equipment normally moves, and can accurately judge the PT secondary circuit multipoint earthing on-line monitoring instrument of multipoint earthing hidden danger.
The technical scheme that the utility model adopts for its technical matters:
The utility model is comprised of pulpit one point earth connecting line, lightning arrester F, milliammeter A, pocket knife lock K and the rheochord R of PT secondary circuit; Described pulpit one point earth connecting line is connected between the pulpit zero phase N600 and secondary equipotential earth mat B of PT secondary circuit; It is in parallel with described pulpit one point earth connecting line after described milliammeter A, pocket knife lock K and rheochord R connect successively; Described lightning arrester F is connected between pulpit zero phase N600 and the secondary equipotential earth mat B.
Described lightning arrester F adopts low-voltage ZnO lightning arrester, and its voltage breakdown is 380V.
The Standard resistance range of described rheochord R is 0-10 Ω; The precision of described milliammeter A is 1mA, and range is 0-100 mA; The rated voltage of described pocket knife lock K is more than the 220V, and rated current is more than the 20A.
The beneficial effects of the utility model are as follows:
Feasible in the substation field simulated experiment, do not lose earth point and do not affect under the prerequisite that protection equipment normally moves at the PT secondary circuit that guarantees operation, can accurately judge the hidden danger of multipoint earthing, provide technical guarantee to the relay protection hidden troubles removing.
Description of drawings
Fig. 1 is the circuit theory diagrams of PT secondary circuit multipoint earthing on-line monitoring instrument.
Fig. 2 is the equivalent circuit diagram of PT secondary circuit one point earth.
Fig. 3 is the equivalent circuit diagram of 2 ground connection of PT secondary circuit.
In Fig. 1-3,1 for pulpit one point earth connecting line, the F of PT secondary circuit be that lightning arrester, A are that milliammeter, K are that little disconnecting link, R are that rheochord, C are over the ground distributed capacitance, U of PT secondary circuit cable 1For threshold voltage, the O such as PT secondary are that one point earth point, the F of substation PT secondary loop in the pulpit is another earth point, the U of substation PT secondary loop except the one point earth point O of pulpit 2Be electric potential difference, the R that exists on secondary equipotential ground between earth point O and the earth point F on the net fBe the cable resistance between earth point O and the earth point F.
Embodiment
By embodiment shown in Figure 1 as can be known, the utility model is comprised of pulpit one point earth connecting line 1, lightning arrester F, milliammeter A, pocket knife lock K and the rheochord R of PT secondary circuit; Described pulpit one point earth connecting line 1 is connected between the pulpit zero phase N600 and secondary equipotential earth mat B of PT secondary circuit; It is in parallel with described pulpit one point earth connecting line 1 after described milliammeter A, pocket knife lock K and rheochord R connect successively; Described lightning arrester F is connected between pulpit zero phase N600 and the secondary equipotential earth mat B.
Described lightning arrester F adopts low-voltage ZnO lightning arrester, and its voltage breakdown is 380V.
The Standard resistance range of described rheochord R is 0-10 Ω; The precision of described milliammeter A is 1mA, and range is 0-100 mA; The rated voltage of described pocket knife lock K is more than the 220V, and rated current is more than the 20A.
The pulpit one point earth connecting line 1 of described PT secondary circuit is 4mm 2The multiply annealed copper wire; The effect of described lightning arrester F is to prevent because after a variety of causes PT secondary circuit loses earth point, to secondary equipotential earth mat B potential rise, the crisis person and device security are after lightning arrester F punctures, the PT secondary circuit meets secondary equipotential earth mat B again, thereby has guaranteed the person and device security; The effect of described milliammeter A is the electric current of measuring branch road.
The using method of present embodiment:
Termination secondary equipotential earth mat B with rheochord R, the end of milliammeter A is linked to each other with pulpit zero phase N600, disconnecting link K closes, take the pulpit one point earth connecting line 1 of PT secondary circuit apart, the resistance of regulating rheochord R changes between 0-10 Ω, electric current on the rheochord R is observed the current value of namely observing milliammeter A change, show if the current value of milliammeter A changes to have multipoint earthing, otherwise do not have multipoint earthing.
When there is one point earth in the pulpit of PT secondary circuit zero phase N600 (referring to Fig. 2), the PT secondary circuit cable is distributed capacitance C, the equivalent voltage U of PT secondary over the ground 1Form the loop with the pulpit one point earth connecting line 1 of PT secondary circuit.C is very little for distributed capacitance, is high impedance, capacitor C capacitive reactance and U 1Determine the size of loop current I.Slide wire resistor R is connected in parallel at pulpit one point earth connecting line 1 place, after taking pulpit one point earth connecting line 1 apart, because of R<<(1/jwC), so change the resistance (less than 10 Ω) of slide wire resistor R, do not affect loop current I, the size of I remains unchanged.
When existing multipoint earthing, the pulpit of PT secondary circuit zero phase N600 (analyzes as an example of 2 ground connection example, referring to Fig. 3), the substation PT secondary loop also has earth point F except 1 the O ground connection in pulpit, and there is electric potential difference U in two earth points at secondary equipotential earth mat B 2, the cable resistance of establishing between earth point F and the earth point O is R f, R fStandard resistance range be 1-5 Ω; Slide wire resistor R is connected in parallel at pulpit one point earth connecting line 1 place; After taking pulpit one point earth connecting line 1 apart, can be drawn by Fig. 3: I=U 2/ (R+R f).When R=0 Ω, I=U 2/ R f, when R=10 Ω, I=U 2/ (R+R f), because the Standard resistance range of rheochord R is 0-10 Ω; When therefore rheochord R being transferred to 10 Ω by 0 Ω, electric current I will significantly reduce.
Hence one can see that, and changing impact on current value by loop resistance, can to judge whether to exist multipoint earthing be feasible in theory.
The present embodiment on-site verification: simulation test can be carried out in conjunction with 10KV II section full cut-off just at comprehensive reformation in the Dong Si station in the recent period.Zero phase N600 at PT cabinet place adds 0.05V voltage, at 10KV562 shunt PT secondary circuit place, zero phase N600 is linked to each other with secondary equipotential earth mat B, at 10KV public testing screen place, the end of milliammeter A of the present utility model is linked to each other with pulpit zero phase N600, termination secondary equipotential earth mat B with rheochord R, pocket knife lock K closes, disconnect pulpit one point earth connecting line 1, rheochord R is transferred to 10 Ω by 0 Ω, current value has become 5mA by 50mA, and explanation this moment exists and also have other earth point except the one point earth of pulpit; Take the grounding connection line at 562 shunt PT secondary circuit places apart, rheochord R is transferred to 10 Ω by 0 Ω, current value is almost nil, and does not change, and this moment, there was not multipoint earthing in explanation.Repeatedly test, the result is unified.

Claims (3)

1. a PT secondary circuit multipoint earthing on-line monitoring instrument is characterized in that being comprised of pulpit one point earth connecting line (1), lightning arrester F, milliammeter A, pocket knife lock K and the rheochord R of PT secondary circuit; Described pulpit one point earth connecting line (1) is connected between the pulpit zero phase N600 and secondary equipotential earth mat B of PT secondary circuit; It is in parallel with described pulpit one point earth connecting line (1) after described milliammeter A, pocket knife lock K and rheochord R connect successively; Described lightning arrester F is connected between pulpit zero phase N600 and the secondary equipotential earth mat B.
2. PT secondary circuit multipoint earthing on-line monitoring instrument according to claim 1 is characterized in that described lightning arrester F adopts low-voltage ZnO lightning arrester, and its voltage breakdown is 380V.
3. PT secondary circuit multipoint earthing on-line monitoring instrument according to claim 1, the Standard resistance range that it is characterized in that described rheochord R is 0-10 Ω; The precision of described milliammeter A is 1mA, and range is 0-100 mA; The rated voltage of described pocket knife lock K is more than the 220V, and rated current is more than the 20A.
CN 201220311316 2012-06-29 2012-06-29 PT (potential transformer) secondary loop multipoint grounding online monitor Expired - Fee Related CN202649370U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 201220311316 CN202649370U (en) 2012-06-29 2012-06-29 PT (potential transformer) secondary loop multipoint grounding online monitor

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Application Number Priority Date Filing Date Title
CN 201220311316 CN202649370U (en) 2012-06-29 2012-06-29 PT (potential transformer) secondary loop multipoint grounding online monitor

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103323745A (en) * 2013-06-21 2013-09-25 深圳供电局有限公司 Method and device for monitoring and locating hidden defect of TV secondary neutral line for relay protection
CN103983895A (en) * 2014-04-08 2014-08-13 广西电网公司电力科学研究院 PT secondary circuit online N-line multipoint ground fault detection method and device
CN104777405A (en) * 2015-04-30 2015-07-15 国家电网公司 Passive voltage transformer secondary circuit N600 multipoint grounding finder and operation method thereof
CN105589004A (en) * 2014-10-13 2016-05-18 国家电网公司 Method and device for judging substation relay protection-used PT secondary common circuit single-point grounding
CN105954642A (en) * 2016-06-08 2016-09-21 国网山西省电力公司阳泉供电公司 Portable PT one-point grounding tester
CN106772192A (en) * 2016-12-12 2017-05-31 国家电网公司 Secondary Circuit of Potential Transformer multipoint earthing detection means

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103323745A (en) * 2013-06-21 2013-09-25 深圳供电局有限公司 Method and device for monitoring and locating hidden defect of TV secondary neutral line for relay protection
CN103983895A (en) * 2014-04-08 2014-08-13 广西电网公司电力科学研究院 PT secondary circuit online N-line multipoint ground fault detection method and device
CN103983895B (en) * 2014-04-08 2016-08-17 广西电网公司电力科学研究院 The online N line multipoint earth faults detection method of PT secondary circuit
CN105589004A (en) * 2014-10-13 2016-05-18 国家电网公司 Method and device for judging substation relay protection-used PT secondary common circuit single-point grounding
CN104777405A (en) * 2015-04-30 2015-07-15 国家电网公司 Passive voltage transformer secondary circuit N600 multipoint grounding finder and operation method thereof
CN104777405B (en) * 2015-04-30 2018-07-31 国家电网公司 Passive type Secondary Circuit of Potential Transformer N600 multipoint earthing locators and its operation method
CN105954642A (en) * 2016-06-08 2016-09-21 国网山西省电力公司阳泉供电公司 Portable PT one-point grounding tester
CN106772192A (en) * 2016-12-12 2017-05-31 国家电网公司 Secondary Circuit of Potential Transformer multipoint earthing detection means

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C14 Grant of patent or utility model
GR01 Patent grant
ASS Succession or assignment of patent right

Owner name: STATE ELECTRIC NET CROP.

Free format text: FORMER OWNER: SHIJIAZHUANG POWER SUPPLY COMPANY

Effective date: 20130410

Owner name: HEBEI ELECTRIC POWER CORPORATION SHIJIAZHUANG POWE

Effective date: 20130410

C41 Transfer of patent application or patent right or utility model
COR Change of bibliographic data

Free format text: CORRECT: ADDRESS; FROM: 050091 SHIJIAZHUANG, HEBEI PROVINCE TO: 100031 XICHENG, BEIJING

TR01 Transfer of patent right

Effective date of registration: 20130410

Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing

Patentee after: State Grid Corporation of China

Patentee after: Hebei Electric Power Corporation

Patentee after: Shijiazhuang Power Supply Co.,Ltd.

Address before: 050091 No. 529 South China Avenue, Hebei, Shijiazhuang

Patentee before: Shijiazhuang Power Supply Co.,Ltd.

CF01 Termination of patent right due to non-payment of annual fee
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20130102

Termination date: 20180629