CN205017000U - Power plant earth fault protection device - Google Patents
Power plant earth fault protection device Download PDFInfo
- Publication number
- CN205017000U CN205017000U CN201520780887.0U CN201520780887U CN205017000U CN 205017000 U CN205017000 U CN 205017000U CN 201520780887 U CN201520780887 U CN 201520780887U CN 205017000 U CN205017000 U CN 205017000U
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- CN
- China
- Prior art keywords
- power plant
- ground
- relay
- circuit breaker
- circuit
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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
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Abstract
The utility model discloses a power plant earth fault protection device, including ground protective relay and circuit breaker, ground protective relay's coil inserts zero sequence circuit, and the circuit breaker is connected on the three -phase power in power plant line, and ground protective relay's normally open contact establishes ties on a set of 220V alternating current circuit in power plant with a set of trip coil of circuit breaker. The utility model provides a power plant ground connection protection device, because the coil with ground protective relay inserts zero sequence circuit, ground protective relay's normally closed contact more changes normally open contact into in the protection return circuit to establish ties on the 220V alternating current circuit in power plant with the trip coil of circuit breaker, structurally anti -vibration performance can poor problem to have avoided normally closed contact, effectively prevents the malfunction in ground protection return circuit, very big improvement power plant security and the reliability moved, little to the change of the original electric loop in power plant simultaneously, work load is few, and is with low costs, easy to carry out.
Description
Technical field
The utility model belongs to power-plant operation protection field, is specifically related to a kind of station grounding failure protecting device.
Background technology
Now, along with the automatic operating degree in power plant is more and more higher, all kinds of protective loop in power plant and protective device also get more and more.The earth-fault protection in power plant is in all types of protective device in power plant extremely important one, the quality of its performance, and whether directly have influence on power plant can normally and economical operation.
In the prior art, the earth protective device in power plant is made up of ground(preference) relay and frame-type circuit breaker, its circuit theory diagrams are as shown in Figure 1: ground(preference) relay LDJ is current mode instantaneous operation electromagnetic type relay, its relay coil access zero sequence loop TA, the normally-closed contact of ground(preference) relay LDJ is connected with the undervoltage trip coil of frame-type circuit breaker incoming transport 380V loop; Upon the occurrence of a ground fault, the electric current of zero sequence loop TA reaches set point, then the coil of ground(preference) relay LDJ powers on, the normally-closed contact of ground(preference) relay LDJ disconnects, undervoltage trip coil dead electricity, switch trip, ground protection action, is grounded defencive function; In addition, frame-type circuit breaker also with breaking coil and closing coil, circuit breaker trip when breaking coil is charged, breaker closing when closing coil is charged.
But, because the environment in power plant is comparatively severe, during normal operation, have larger vibration.The normally-closed contact of relay is due to the problem of self structure, and under vibration environment condition, normally-closed contact may disconnect voluntarily, concrete principle as shown in Figure 2: the normally closed node of relay and Chang Kai node are kept by the movable contact spring of in relay.The vibration mark acceleration that so relay bears is that movable contact spring makes relay normally-closed contact group keep normally closed to can bear the limiting value of casing vibration acceleration, and movable contact spring is equivalent to one end and fixes the uniform cantilever beam that the other end has " weight " (contact).Cantilever beam has certain initial deflection and initial pressure F
o.When relay makes reed that vibration occurs under vibration environment condition, namely contact force changes, and the vanishing when vibration overload reaches certain numerical value, the critical condition before normally-closed contact loop disconnection that Here it is.Therefore, normally-closed contact contact is kept well can to describe with following formula
F
o≥F
j
F in formula
jfor the reaction force of contact point, which determine contact force value.
F
j＞F
o
When the reaction force of contact point is greater than initial pressure, normally closed contact will disconnect voluntarily, and this is the structural reason that normally-closed contact disconnects voluntarily.
Because the protection relay installation site in power plant often vibrates; the normally-closed contact of ground(preference) relay is caused to disconnect voluntarily in the uncharged situation of coil; thus cause the undervoltage trip coil dead electricity of frame-type circuit breaker; switch trip; cause the misoperation in station grounding loop, have a strong impact on safety and the economical operation in power plant.
Utility model content
The purpose of this utility model is to provide a kind of station grounding failure protecting device of reliable and stable, error-free motion.
This station grounding failure protecting device that the utility model provides; comprise ground(preference) relay LDJ and circuit breaker MN; the coil access zero sequence loop TA of ground(preference) relay LDJ; circuit breaker MN is connected in the three-phase power line in power plant, it is characterized in that the normally opened contact of ground(preference) relay LDJ and one group of breaking coil F of circuit breaker MN are connected on one group, power plant 220V ac circuit.
Described relay adopts current relay.
Described current relay is instantaneous operation electromagnetic type relay.
Described circuit breaker adopts frame-type circuit breaker.
The station grounding protective device that the utility model provides, due to the coil of ground(preference) relay is accessed zero sequence loop, the normally-closed contact of protective loop repeat circuit is replaced with normally opened contact, and be connected on the 220V ac circuit in power plant with the breaking coil of circuit breaker, avoid the problem of normally-closed contact structurally shock resistance difference, effectively prevent the misoperation of earth fault protection circuit, greatly improve the safety and reliability of power-plant operation; Change little to the original electric loop in power plant, workload is few, and cost is low, easy to implement simultaneously.
Accompanying drawing explanation
Fig. 1 is the circuit connection diagram of prior art.
Fig. 2 is prior art repeat circuit contact schematic diagram.
Fig. 3 is the circuit connection diagram of the utility model station grounding protective device.
Embodiment
As shown in Figure 3, the circuit connection diagram of the station grounding protective device provided for the utility model; Power plant protective device comprises the breaking coil (indicating F in figure) of the coil (indicating LDJ in figure) of ground(preference) relay, the normally opened contact (indicating 1LDJ in figure) of ground(preference) relay and circuit breaker.In figure, the coil of ground(preference) relay is still connected in the TA of zero sequence loop; One group of normally opened contact of ground(preference) relay and the breaking coil of circuit breaker are connected in one group of 220V ac circuit in power plant, constitute earth-fault protection; The ground protection that the device (indicating LP in figure) of connecting with the normally opened contact of ground(preference) relay in figure is power plant is thrown and is moved back pressing plate; putting into operation or cutting off the access of earth protective device for earth protective device is the connected state of short circuit when normal operation.When power plant normally runs, electric current is not had in the TA of zero sequence loop, the coil of ground(preference) relay is not charged, the normally opened contact of ground(preference) relay and the breaking coil of circuit breaker are connected in one group of 220V ac circuit in power plant, and the node (indicating 36 in figure) when switch (indicating SQ in figure) normally runs and in circuit is connected; Once there is earth fault in power plant; zero-sequence current will be produced in the TA of zero sequence loop; the coil of ground(preference) relay is by charged; the normally opened contact of ground(preference) relay will close; connect the 220V ac circuit at normally opened contact and circuit breaker trip coil place, the breaking coil of circuit breaker will power on, and circuit breaker will trip power-off immediately; system auto-breaking is protected, and ensure that the security of operation in power plant.
Claims (4)
1. a station grounding failure protecting device; comprise ground(preference) relay and circuit breaker; the coil access zero sequence loop of ground(preference) relay; circuit breaker is connected in the three-phase power line in power plant, it is characterized in that the normally opened contact of ground(preference) relay and one group of breaking coil of circuit breaker are connected on one group, power plant 220V ac circuit.
2. station grounding failure protecting device according to claim 1, is characterized in that described relay adopts current relay.
3. station grounding failure protecting device according to claim 2, is characterized in that described current relay is instantaneous operation electromagnetic type relay.
4., according to the station grounding failure protecting device one of claim 1 ~ 3 Suo Shu, it is characterized in that described circuit breaker adopts frame-type circuit breaker.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520780887.0U CN205017000U (en) | 2015-10-10 | 2015-10-10 | Power plant earth fault protection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520780887.0U CN205017000U (en) | 2015-10-10 | 2015-10-10 | Power plant earth fault protection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205017000U true CN205017000U (en) | 2016-02-03 |
Family
ID=55215584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520780887.0U Expired - Fee Related CN205017000U (en) | 2015-10-10 | 2015-10-10 | Power plant earth fault protection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205017000U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107482592A (en) * | 2017-06-29 | 2017-12-15 | 中石油北方工程设计有限公司 | A kind of station grounding fault protection system |
| CN109066590A (en) * | 2018-08-03 | 2018-12-21 | 河南森源电气股份有限公司 | A kind of ground protection circuit and motor power supply system |
-
2015
- 2015-10-10 CN CN201520780887.0U patent/CN205017000U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107482592A (en) * | 2017-06-29 | 2017-12-15 | 中石油北方工程设计有限公司 | A kind of station grounding fault protection system |
| CN109066590A (en) * | 2018-08-03 | 2018-12-21 | 河南森源电气股份有限公司 | A kind of ground protection circuit and motor power supply system |
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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: 20160203 Termination date: 20171010 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |