CN209088533U - Gas power station two-stage small current grounding protection control system - Google Patents
Gas power station two-stage small current grounding protection control system Download PDFInfo
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- CN209088533U CN209088533U CN201821942004.1U CN201821942004U CN209088533U CN 209088533 U CN209088533 U CN 209088533U CN 201821942004 U CN201821942004 U CN 201821942004U CN 209088533 U CN209088533 U CN 209088533U
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Abstract
The utility model discloses a kind of gas power station two-stage small current grounding protection control systems, the neutral point of unit G1-Gn is connected respectively to one end of respectively neutral point-contactor JC1-JCn, the other end of JC1-JCn is connected on common neutral copper bar NN, the common neutral copper bar NN shares one end of small resistance RL by contactor JC0 connection, the common neutral copper bar NN shares one end of big resistance RH by disconnecting switch SW0 connection, the small resistance RL and the big resistance RH other end are connect with grounded screen, it shares zero sequence current mutual inductor CT0 and detects the small resistance RL loop fault electric current；Utility model has the advantages that intelligent recognition fault coverage, improves system protection performance and efficiency, extends service life of equipment.
Description
Technical field
The utility model relates to a kind of ground protection control system, specifically a kind of gas power station two-stage low current
Ground protection control system belongs to ground protection control system field.
Background technique
In distributed busbar protection, due to jet dynamic control as normal operating unit and often in the form of multimachine and machine
It with power grid paired running, protects system cooperation complicated, therefore electrical protection systems is correctly identified between fault coverage and system
Reliable fit has higher requirements.Standard provides that 6-35KV medium voltage distribution network uses neutral non-effective grounding mode, i.e. low current
Earthing mode, so the usual resistance grounded of 10KV and 6KV voltage class generator neutral point, engineering is in practice and in electromechanical station
Property point resistance there are many grounding schemes.
As power distribution network develops, especially cable run increases, and is continuously increased electric capacity and current with single-phase earthing in system, causes
System single-phase earth fault development is that the probability of accident improves, and capacitance current and system stray electrical current make big resistance value neutral point
The sensitivity of ground protection is also a greater impact.Mostly use low resistance neutral point protection at present, when system single-phase earthing, control
Current in the fault point is in 100A to starting zero-sequenceprotection between 500A.The sensitivity of low resistance neutral point protection is preferable and can reduce
Apparatus insulated cost, once however zero-sequenceprotection tripping or not in time, since fault current is larger, will lead to exhausted near fault point
Edge is by bigger harm, or even expands as phase-to phase fault；In addition, of short duration or continuous earth failure acts on tripping, make user
Line tripping number increases, power supply reliability decline.
More seriously, when being grounded inside Gas Generator Set generator windings, biggish fault current can be damaged seriously
Bad equipment is even scrapped.The neutral point protection system that pressure and electromechanical station use at present, the fault point to any range be all by
According to the low resistance equipment adjusting selected, inside the gas electricity generator when winding failure, although breaker open operation is by failure unit
Cut off from system, but unit moment emergency stop must also be set, otherwise larger fault current persistently to winding failure point power and
Badly damaged generator；However the unexpected emergency stop of unit of long-time run with load, again to gas engine and critical component service life
It is extremely harmful.This is the contradiction for having to solve.
In currently used several neutral point schemes, to above situation consider and take into account deficiency, especially when unit around
When group ground fault and processing, reduction generator and engine damage are not combined.The first common approach is every
Unit has neutral point device independent, the disadvantage is that multicomputer provides power supply, especially generator windings to earth fault
When ground fault, it is enough badly damaged generator within the system mating protection time；Second scheme is in the first scheme
In each neutral point install controllable a contactor or switch additional, the neutrality of a unit is whenever only selected in operating unit
Point resistance put into operation, major defect is that equipment is more, when the unit that neutral point puts into operation do not close a floodgate and multimachine starting rise
During speed, all units are isolated neutral and system are made to be in the precarious position for losing ground protection, and due to low-resistance
It is worth neutral point protection, the electric current damage problem of generator windings ground connection still has；The third scheme is all unit neutral points
By a resistance eutral grounding after connection, the disadvantage is that any point ground fault can all make the unit in stoppage in transit maintenance be in high potential
Precarious position, and increase triple-frequency harmonics circulation circuit.
Summary of the invention
To solve the above-mentioned problems, the utility model devises a kind of gas power station two-stage small current grounding protection control
System improves work efficiency, and extends service life of equipment.
The technical solution of the utility model are as follows:
Gas power station two-stage small current grounding protection control system, for N platform jet dynamic control G1-Gn and machine station,
Specifically include that neutral point shares small resistance RL and contactor JC0, neutral point share big resistance RH and disconnecting switch SW0, share zero
Sequence current protective relay ZR and shared zero sequence current mutual inductor CT0, controller PLC, unit neutrality point-contactor JC1-JCn,
Unit differential protector D1-Dn, differential current transformer CT11/CT12-CTn1/CTn2, unit breaker CB1-CBn；
The neutral point of unit G1-Gn is connected respectively to one end of respectively neutral point-contactor JC1-JCn, and JC1-JCn's is another
One end is connected on common neutral copper bar NN, and the common neutral copper bar NN shares small resistance by contactor JC0 connection
One end of RL, the common neutral copper bar NN share one end of big resistance RH, the small electricity by disconnecting switch SW0 connection
Resistance RL and the big resistance RH other end are connect with grounded screen, are shared zero sequence current mutual inductor CT0 and are detected the circuit small resistance RL
Fault current；
Unit G1-Gn respectively through respective outlet breaker CB1-CBn be connected to it is middle pressure bus-bar system and machine bus, it is described
And machine bus external connection network system and distribution load route on the spot；Generator output end differential current transformer CT11-
CTn1 and power generation machine tail end differential current transformer CT12-CTn2 are separately input to corresponding unit differential protector D1-Dn, described
Differential protector D1-Dn controls corresponding machine set outlet breaker protection separating brake respectively；Controller PLC believes through control loop and position
Number feedback loop is separately connected: unit neutrality point-contactor JC1-JCn and contactor JC0, sharing residual current relay ZR, machine
Group differential relay D1-Dn, unit breaker CB1-CBn.
System normal operating mode is that the disconnecting switch SW0 of resistance RH keeps normally closed, and resistance RL is closed through contactor JC0
It puts into operation, according to the parameter of 6KV-10KV not homologous ray, resistance RL configures specification limit and configures in 100A-500A, resistance RH
It can be 10A-20A, valued resistor RH should be 10 times of RL or more；It runs in the unit with load, in only one unit
Property point-contactor JC1-JCn puts into operation, other units JC is disconnected locking；The investment of any contactor JC1-JCn is latched item
Part is that existing operating unit contactor JC puts into operation；It is that unit all starts and do not have that whole JC1-JCn, which put into condition simultaneously,
Organic assembling lock, that closes a floodgate first is kept in contact device JC investment, remaining contactor JC is exited；Any contactor JC1-JCn investment
Condition is that unit fault-free starts or run and do not detect other units JC investment and the movement of unit G1-Gn differential protection
It exports and trips；It is that unit G1-Gn shutdown is exited or differential separating brake and unit in the disconnection condition of operation contactor JC1-JCn
G1-Gn completes cooling shut down and has dropped out；Contactor JC0 exit criteria is, any unit differential protector D1-Dn movement output and
Differential failure unit does not complete cooling shut down；Contactor SW0 is only exited when resistance RH is repaired.
The judgement of fault coverage is handled.When exterior singlephase earth fault, for example, fault point F1, this system ground protection
Selective protection is carried out by proper engagement adjusting with distribution system, cuts off failure by external respective circuit breakers.And machine bus ranges
When ground fault, such as fault point F2, unit differential protector D1-Dn will not be acted, but Current Transmit 0 and system electricity
Pressure mutual inductor open delta has protection to alarm, and controller PLC is judged as external fault, and contactor group does not need to act, this system
It is acted according to the sensitivity protection rule and setting time limit of small resistance RL/CT0 detection earth current, in F2, institute is organic for fault point
Cooling shutdown is taken when group is by cooperation time limit separating brake.Situation as shown in Figure 1, fault point is in F3, differential protection attonity, institute
In failure unit G1-Gn if it is JCi(i=1-n) investment state then still takes cooling shutdown after separating brake, if JCi is not to throw
Entering state then leads to unit Gi independently earth-free state, and non-faulting phase voltage, which increases, threatens to unit Gi insulation, when logic
The more difficult identifying processing of sequence, two measures in response to this are, perhaps carry out split-phase Seal treatment to the position F3 or will be poor
Streaming current mutual inductor CT11-CTn1 is mounted on breaker and machine bus bar side, as shown in Figure 2.In Fig. 2, F3 and F4 at
For the same fault point, belong to the internal fault of differential protection range.
When internal system singlephase earth fault, such as fault point F4, especially generator winding, differential protection Di first
Breaker CBi separating brake is first cut off into failure unit, hereafter in two kinds of situation.The neutral point of the first situation, failure unit Gi connects
Tentaculum JCi is in investment state, and differential Di and zero phase-sequence relay ZR combinational logic throw another unit JC according to priority at this time
Enter and contactor JC0 is exited, whole system is still in neutral ground state by resistance RH, while JCi being kept to continue to throw
Entering state until complete unit exits, unit Gi generator winding faults point in cooling stopping process maintains glitch electric current,
Engine is allowed to be able to normal cooling simultaneously, after unit Gi is exited completely, contactor JCi is exited, contactor JC0 restores investment fortune
Row.Second situation, the neutral point-contactor JCi of failure unit Gi is in off-state, and contactor JC0 is exited at this time, JCi is by patrolling
Investment is collected, other units JC keeps original state, and unit Gi is cooling in small grounding current to shut down, and exits rear JCi completely
It exits, JC0 recovery puts into operation.The above process ensure that system neutral small current neutral grounding holding and other systems normally transport
While row, the damage of the generator and engine of failure unit has all reached minimum.Neutral resistor RL and RH be not for
Adaptable effect has been each served as with situation, has constituted two-stage small current grounding protection system.
Logical process is completed by programmable controller PLC, controller PLC status monitoring object include contactor JC1-JCn,
Contactor JC0, residual current relay ZR, differential protection relay D1-Dn, breaker CB1-CBn；Controller PLC control pair
As including contactor JC1-JCn, contactor JC0；The controller communication monitoring unit data of controller PLC and unit G1-Gn.
Utility model has the advantages that
(1) when any generator winding earth failure, neutral dot system automatically switches to minimum fault current ground connection
Mode while so that system is continued to keep the safe condition of neutral non-effective grounding, allows failure unit is normally cooling to shut down,
To make generator and engine damage minimize；
(2) only whole station ground connection can be realized with a set of two neutral resistors (a small resistance and a big resistance) in whole station
It is convenient for safeguarding to save equipment for defencive function, and keeps single supply neutral ground by neutral point-contactor control, guarantees simultaneously
System is not in the precarious position of isolated neutral, stoppage in transit maintenance unit will not occurs by neutral point circuit and return to band
Electricity；
(3) ground fault point range is judged, uses unit differential protection and combine shared zero-sequenceprotection, outside connects
Using sensitive small resistance protection, unit inner ground then switches big resistance in conjunction with differential and zero-sequenceprotection, accuracy and spirit on ground
The technology realization of sensitivity is more more reliable than zero sequence power direction, realizes system protection cooperation greatly simplified.
The utility model is described in further detail with reference to the accompanying drawings and examples.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of the utility model embodiment；
Fig. 2 is another structural schematic diagram of the utility model embodiment.
Specific embodiment
The preferred embodiment of the utility model is illustrated below, it should be understood that preferred embodiment described herein
It is only used for describing and explaining the present invention, is not used to limit the utility model.
Embodiment 1
A kind of gas power station two-stage small current grounding protection control system, for N platform jet dynamic control G1-Gn and machine
It stands, specifically includes that neutral point shares small resistance RL and contactor JC0, neutral point share big resistance RH and disconnecting switch SW0, are total to
With zero-sequence current protection relay ZR and shared zero sequence current mutual inductor CT0, controller PLC, unit neutrality point-contactor JC1-
JCn, unit differential protector D1-Dn, differential current transformer CT11/CT12-CTn1/CTn2, unit breaker CB1-CBn；
As shown in Figure 1, the neutral point of unit G1-Gn is connected respectively to one end of respectively neutral point-contactor JC1-JCn,
The other end of JC1-JCn is connected on common neutral copper bar NN, and the common neutral copper bar NN passes through contactor JC0 connection
One end of small resistance RL is shared, the common neutral copper bar NN shares one end of big resistance RH by disconnecting switch SW0 connection,
The small resistance RL and the big resistance RH other end are connect with grounded screen, and it is described small to share zero sequence current mutual inductor CT0 detection
Resistance RL loop fault electric current；
Unit G1-Gn respectively through respective outlet breaker CB1-CBn be connected to it is middle pressure bus-bar system and machine bus, it is described
And machine bus external connection network system and distribution load route on the spot；Generator output end differential current transformer CT11-
CTn1 and power generation machine tail end differential current transformer CT12-CTn2 are separately input to corresponding unit differential protector D1-Dn, described
Differential protector D1-Dn controls corresponding machine set outlet breaker protection separating brake respectively；Controller PLC believes through control loop and position
Number feedback loop is separately connected: unit neutrality point-contactor JC1-JCn and contactor JC0, sharing residual current relay ZR, machine
Group differential relay D1-Dn, unit breaker CB1-CBn.
System normal operating mode is that the disconnecting switch SW0 of resistance RH keeps normally closed, and resistance RL is closed through contactor JC0
It puts into operation, according to the parameter of 6KV-10KV not homologous ray, resistance RL configures specification limit and configures in 100A-500A, resistance RH
It can be 10A-20A, valued resistor RH should be 10 times of RL or more；It runs in the unit with load, in only one unit
Property point-contactor JC1-JCn puts into operation, other units JC is disconnected locking；The investment of any contactor JC1-JCn is latched item
Part is that existing operating unit contactor JC puts into operation；It is that unit all starts and do not have that whole JC1-JCn, which put into condition simultaneously,
Organic assembling lock, that closes a floodgate first is kept in contact device JC investment, remaining contactor JC is exited；Any contactor JC1-JCn investment
Condition is that unit fault-free starts or run and do not detect other units JC investment and the movement of unit G1-Gn differential protection
It exports and trips；It is that unit G1-Gn shutdown is exited or differential separating brake and unit in the disconnection condition of operation contactor JC1-JCn
G1-Gn completes cooling shut down and has dropped out；Contactor JC0 exit criteria is, any unit differential protector D1-Dn movement output and
Differential failure unit does not complete cooling shut down；Contactor SW0 is only exited when resistance RH is repaired.
The judgement of fault coverage is handled.When exterior singlephase earth fault, for example, fault point F1, this system ground protection
Selective protection is carried out by proper engagement adjusting with distribution system, cuts off failure by external respective circuit breakers.And machine bus ranges
When ground fault, such as fault point F2, unit differential protector D1-Dn will not be acted, but Current Transmit 0 and system electricity
Pressure mutual inductor open delta has protection to alarm, and controller PLC is judged as external fault, and contactor group does not need to act, this system
It is acted according to the sensitivity protection rule and setting time limit of small resistance RL/CT0 detection earth current, in F2, institute is organic for fault point
Cooling shutdown is taken when group is by cooperation time limit separating brake.Situation as shown in Figure 1, fault point is in F3, differential protection attonity, institute
In failure unit G1-Gn if it is JCi(i=1-n) investment state then still takes cooling shutdown after separating brake, if JCi is not to throw
Entering state then leads to unit Gi independently earth-free state, and non-faulting phase voltage, which increases, threatens to unit Gi insulation, when logic
The more difficult identifying processing of sequence, two measures in response to this perhaps carry out split-phase Seal treatment or will be differential to the position F3
Current Transmit 11-CTn1 is mounted on breaker and machine bus bar side, as shown in Figure 2.In Fig. 2, F3 and F4 become
The same fault point belongs to the internal fault of differential protection range.
When internal system singlephase earth fault, such as fault point F4, especially generator winding, differential protection Di first
Breaker CBi separating brake is first cut off into failure unit, hereafter in two kinds of situation.The neutral point of the first situation, failure unit Gi connects
Tentaculum JCi is in investment state, and differential Di and zero phase-sequence relay ZR combinational logic throw another unit JC according to priority at this time
Enter and contactor JC0 is exited, whole system is still in neutral ground state by resistance RH, while JCi being kept to continue to throw
Entering state until complete unit exits, unit Gi generator winding faults point in cooling stopping process maintains glitch electric current,
Engine is able to normal cooling simultaneously, and after unit Gi is exited completely, contactor JCi is exited, contactor JC0 recovery puts into operation.
Second situation, the neutral point-contactor JCi of failure unit Gi is in off-state, and contactor JC0 is exited at this time, JCi is by logic
Investment, other units JC keep original state, and unit Gi is cooling in small grounding current to shut down, and exit rear JCi completely and move back
Out, JC0 recovery puts into operation.The above process ensure that system neutral small current neutral grounding holding and other systems normal operation
While, the damage of the generator and engine of failure unit has all reached minimum.Neutral resistor RL and RH are for difference
Situation has each served as adaptable effect, constitutes two-stage small current grounding protection system.
Logical process is completed by programmable controller PLC, and controller PLC uses siemens PLC SMART controller,
Programming software version number is STEP7-MicroWIN SMART V2.3.Controller PLC status monitoring object includes contactor JC1-
JCn, contactor JC0, residual current relay ZR, differential protection relay D1-Dn, breaker CB1-CBn；Controller PLC control
Object processed includes contactor JC1-JCn, contactor JC0；Controller PLC is communicated with the controller of unit G1-Gn to monitor unit
Data.
Claims (3)
1. gas power station two-stage small current grounding protection control system, it is characterised in that: be directed to N platform jet dynamic control G1-
Gn and machine station, specifically include that neutral point shares small resistance RL and contactor JC0, neutral point share big resistance RH and disconnecting switch
SW0, zero-sequence current protection relay ZR and shared zero sequence current mutual inductor CT0, controller PLC, unit neutrality point contact are shared
Device JC1-JCn, unit differential protector D1-Dn, differential current transformer CT11/CT12-CTn1/CTn2, unit breaker
CB1-CBn；
The neutral point of unit G1-Gn is connected respectively to one end of respectively neutral point-contactor JC1-JCn, the other end of JC1-JCn
It is connected on common neutral copper bar NN, the common neutral copper bar NN shares small resistance RL's by contactor JC0 connection
One end, the common neutral copper bar NN share one end of big resistance RH, the small resistance RL by disconnecting switch SW0 connection
It is connect with grounded screen with the big resistance RH other end, shares zero sequence current mutual inductor CT0 and detect the small resistance RL loop fault
Electric current.
2. gas power station two-stage small current grounding protection control system according to claim 1, it is characterised in that: unit
G1-Gn is connected to middle pressure bus-bar system through respective outlet breaker CB1-CBn respectively and machine bus, outside described and machine bus
Connect network system and on the spot distribution load route；Generator output end differential current transformer CT11-CTn1 and power generation tail
End differential current transformer CT12-CTn2 is separately input to corresponding unit differential protector D1-Dn, the differential protector D1-
Dn controls corresponding machine set outlet breaker protection separating brake respectively；Controller PLC is through control loop and position signal feedback loop point
Not Lian Jie: unit neutrality point-contactor JC1-JCn and contactor JC0, share residual current relay ZR, unit differential relay
D1-Dn, unit breaker CB1-CBn.
3. gas power station two-stage small current grounding protection control system according to claim 1 or 2, it is characterised in that:
Controller PLC status monitoring object include contactor JC1-JCn, contactor JC0, residual current relay ZR, differential protection after
Electric appliance D1-Dn, breaker CB1-CBn；Controller PLC control object includes contactor JC1-JCn, contactor JC0；Controller
PLC is communicated with the controller of unit G1-Gn to monitor unit data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821942004.1U CN209088533U (en) | 2018-11-23 | 2018-11-23 | Gas power station two-stage small current grounding protection control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821942004.1U CN209088533U (en) | 2018-11-23 | 2018-11-23 | Gas power station two-stage small current grounding protection control system |
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| CN209088533U true CN209088533U (en) | 2019-07-09 |
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| CN201821942004.1U Active CN209088533U (en) | 2018-11-23 | 2018-11-23 | Gas power station two-stage small current grounding protection control system |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111521938A (en) * | 2020-05-06 | 2020-08-11 | 中国大唐集团科学技术研究院有限公司华东电力试验研究院 | One-point grounding diagnosis method and device for generator excitation system |
-
2018
- 2018-11-23 CN CN201821942004.1U patent/CN209088533U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111521938A (en) * | 2020-05-06 | 2020-08-11 | 中国大唐集团科学技术研究院有限公司华东电力试验研究院 | One-point grounding diagnosis method and device for generator excitation system |
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