CN202177679U - One-point grounding detection device for secondary coil neutral wire of voltage transformer - Google Patents
One-point grounding detection device for secondary coil neutral wire of voltage transformer Download PDFInfo
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- CN202177679U CN202177679U CN2011202936018U CN201120293601U CN202177679U CN 202177679 U CN202177679 U CN 202177679U CN 2011202936018 U CN2011202936018 U CN 2011202936018U CN 201120293601 U CN201120293601 U CN 201120293601U CN 202177679 U CN202177679 U CN 202177679U
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- voltage transformer
- secondary coil
- coil neutral
- point
- neutral wire
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Abstract
The utility model discloses an one-point grounding detection device for the secondary coil neutral wire of a voltage transformer. The one-point grounding detection device for the secondary coil neutral wire of a voltage transformer is characterized in that an ammeter and a slide rheostat are connected in a series manner and then are connected between the secondary coil neutral wire of a voltage transformer and an equipotential ground screen; the resistance value of the slide rheostat is adjusted to obtain corresponding current readings in the ammeter; a voltmeter is connected between the secondary coil neutral wire of the voltage transformer and the equipotential ground screen; the variance of the resistance value of the slide rheostat is detected by the voltmeter; a discharging gap and a knife gate switch are respectively connected between the secondary coil neutral wire of the voltage transformer and the equipotential ground screen; and the discharging gap is used for overvoltage protection, and the knife gate switch is used for controlling switch-on and switch-off of the grounding point during the detection. The one-point grounding detection device of the utility model is suitable for grounding reliability detection for the secondary loop of the voltage transformer during operation, allows the correct rate of relay protection motions in a transformer station, and enables safety to be guaranteed.
Description
Technical field
The utility model is the device that the voltage transformer secondary coil neutral line in service (N600) one point earth reliability is detected.
Background technology
Current, transformer substation voltage mutual inductor secondary coil neutral line N600 ground connection reliability in service can't detect, and whether, whether ground connection have multipoint earthing all can not obtain detecting when normally moving.When system's generation earth fault, substation ground network will flow through zero-sequence current, if multipoint earthing is arranged; Then can between two earth points, produce pressure reduction; Cause the protector measuring magnitude of voltage incorrect, wave form distortion causes the incorrect operation of impedor and directional element.If lose earth point, the distributed capacitance between voltage transformer (VT) first and second coil and the ground capacitance of secondary circuit form dividing potential drop, high tension voltage are introduced secondary circuit, the safety of the critical person and secondary device.
" 18 great anti-accident measures of electrical network of State Grid Corporation of China " relay protection specialty emphasis is implemented to require regulation: the secondary circuit of utility voltage mutual inductor only allows that one point earth is arranged in the pulpit; The voltage transformer secondary coil of one point earth in the pulpit, should be at switch yard with the secondary coil neutral point through discharging gap ground connection; Should make regular check on discharging gap, prevent to cause the phenomenon of voltage secondary circuit multipoint earthing.
For satisfying relevant regulations, need a kind of detection method and pick-up unit easily and effectively, be convenient to field personnel's concrete operations and judgement.
The utility model content
The utility model is the weak point for avoiding above-mentioned prior art to exist; A kind of voltage transformer secondary coil neutral line one point earth pick-up unit that is applicable to that voltage transformer secondary in service loop ground connection reliability detects is provided; To improve relay protection action accuracy in the transformer station, guarantee the person and device security.
The utility model technical solution problem adopts following technical scheme.
The characteristics of the utility model voltage transformer secondary coil neutral line one point earth pick-up unit are:
With reometer A be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat after rheochord R connects; Regulate the size of the resistance value of rheochord R, obtain corresponding current indication among the reometer A;
Be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat with voltage table V; Detect the variable quantity of the resistance value of rheochord R with said voltage table V;
Be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat with discharging gap JB and disconnecting link K, carry out overvoltage protection, control in test opening of earth point with disconnected with said disconnecting link K with said discharging gap JB.
The characteristics of the utility model voltage transformer secondary coil neutral line one point earth pick-up unit also are:
The range of said voltage table V is 0-10V;
The range of said reometer A is 0-100mA;
The resistance of said rheochord R is 0-10 Ω;
Said discharging gap JB is the 250V type.
The method that the utility model voltage transformer secondary coil neutral line one point earth pick-up unit detects is:
At first that disconnecting link is closed, remove voltage transformer secondary loop ground wire in the original system, connect test connection, warranty test loop earth point is reliable;
Rheochord R is transferred to 0 Ω, open disconnecting link K, the reading of record reometer A this moment is the reading U1 of I1 and voltage table; Regulate rheochord numerical value, test altogether 5 times, reading Ix and Ux that difference recording ammeter and voltage become, said x is respectively 1,2,3,4,5;
If in process of the test, the reading of reometer does not change, and judges that then voltage transformer secondary coil neutral line N600 loop one point earth is reliable at this moment;
If in process of the test, the reading of reometer changes, and judges that then the voltage transformer secondary coil neutral line N600 loop of this moment has multipoint earthing.
Compared with present technology, the utility model beneficial effect is embodied in:
1, the utility model does not influence the operate as normal of voltage transformer (VT) when detecting earth point, can not influence measurement loop, relay protection circuit, personal equipment is not constituted harm.
2, the utility model compares through the electric current that detection and differential pressure loop to the tank capacitance electric current form, and judges the working condition of earth point, and principle is simple, convenient in application.
Description of drawings
Fig. 1 is the utility model circuit theory diagrams;
Fig. 2 is the capacitance current synoptic diagram;
Fig. 3 causes current diagram for differential pressure;
Embodiment
Referring to Fig. 1, voltage transformer secondary coil neutral line one point earth pick-up unit is set in the present embodiment:
With reometer A be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat after rheochord R connects; Regulate the size of the resistance value of rheochord R, obtain corresponding current indication among the reometer A;
Be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat with voltage table V; Detect the variable quantity of the resistance value of rheochord R with said voltage table V;
Be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat with discharging gap JB and disconnecting link K, carry out overvoltage protection, control in test opening of earth point with disconnected with said disconnecting link K with said discharging gap JB.
In the practical implementation, the range of voltage table V is 0-10V; The range of reometer A is 0-100mA; The resistance of rheochord R is 0-10 Ω; Discharging gap JB is the 250V type.
Test method:
Earlier that disconnecting link is closed, remove voltage transformer secondary loop ground wire in the original system, connect test connection, warranty test loop earth point is reliable.Rheochord R is transferred to 0 Ω, open disconnecting link K, the reading of record reometer A this moment is the reading U1 of I1 and voltage table; Regulate rheochord numerical value, test altogether 5 times, reading Ix and Ux that difference recording ammeter and voltage become, x is respectively 1,2,3,4,5.
If in process of the test; The reading of reometer does not change; Can judge that voltage transformer secondary coil neutral line N600 loop one point earth is reliable at this moment; Only be that the closure with disconnecting link K forms place's ground connection this moment, and judge the place that underproof loop is merely in the test to be removed thus and form one point earth; Its principle is as shown in Figure 2, and the test loop does not have earth point, and the electric current that flows through reometer all is a secondary line capacitance current over the ground, and its size does not change with the change of resistance value, and judging does not have other earth point this moment, and voltage transformer (VT) is in proper working order.
If in process of the test; The reading of reometer changes, and judges that then the voltage transformer secondary coil neutral line N600 loop of this moment has multipoint earthing, in fact is meant; This moment is except the closed place's ground connection that forms of disconnecting link; Voltage transformer secondary coil in the test also has other earth point, judges place's ground connection that underproof voltage transformer secondary coil not only is merely in the test to be removed thus, need continue to search other earth point then; Its principle is as shown in Figure 3.Owing to also have another earth point in the switch yard, be meant the earth point that another is not removed, the electric current of surveying is the formed electric current of differential pressure Δ U between 2 of switch yard and the experimental stations in test this moment; Change loop resistance; According to Ohm law: voltage is constant, and it is big that resistance becomes, and electric current will diminish.Therefore judge the N600 loop and have other earth point.
Claims (2)
1. voltage transformer secondary coil neutral line one point earth pick-up unit is characterized in that:
With reometer A be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat after rheochord R connects; Regulate the size of the resistance value of rheochord R, obtain corresponding current indication among the reometer A;
Be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat with voltage table V; Detect the variable quantity of the resistance value of rheochord R with said voltage table V;
Be connected between the voltage transformer secondary coil neutral line and the equipotential earth mat with discharging gap JB and disconnecting link K, carry out overvoltage protection, control in test opening of earth point with disconnected with said disconnecting link K with said discharging gap JB.
2. voltage transformer secondary coil neutral line one point earth pick-up unit according to claim 1 is characterized in that:
The range of said voltage table V is 0-10V;
The range of said reometer A is 0-100mA;
The resistance of said rheochord R is 0-10 Ω;
Said discharging gap JB is the 250V type.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202936018U CN202177679U (en) | 2011-08-12 | 2011-08-12 | One-point grounding detection device for secondary coil neutral wire of voltage transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011202936018U CN202177679U (en) | 2011-08-12 | 2011-08-12 | One-point grounding detection device for secondary coil neutral wire of voltage transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202177679U true CN202177679U (en) | 2012-03-28 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011202936018U Expired - Fee Related CN202177679U (en) | 2011-08-12 | 2011-08-12 | One-point grounding detection device for secondary coil neutral wire of voltage transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202177679U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102288868A (en) * | 2011-08-12 | 2011-12-21 | 安徽省电力公司淮南供电公司 | One-point grounding detector and detection method for voltage transformer secondary coil neutral line |
| 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 |
| 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 |
| 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 |
-
2011
- 2011-08-12 CN CN2011202936018U patent/CN202177679U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102288868A (en) * | 2011-08-12 | 2011-12-21 | 安徽省电力公司淮南供电公司 | One-point grounding detector and detection method for voltage transformer secondary coil neutral line |
| 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 |
| 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 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120328 Termination date: 20200812 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |