CN104638635A - Power grid neutral point active resistor grounding method - Google Patents
Power grid neutral point active resistor grounding method Download PDFInfo
- Publication number
- CN104638635A CN104638635A CN201310550579.4A CN201310550579A CN104638635A CN 104638635 A CN104638635 A CN 104638635A CN 201310550579 A CN201310550579 A CN 201310550579A CN 104638635 A CN104638635 A CN 104638635A
- Authority
- CN
- China
- Prior art keywords
- phase
- current
- earth
- brachium pontis
- network
- Prior art date
- 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.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a power grid neutral point grounding active resistor method. The method is realized through arranging a power electron commutation assembly and a corresponding detection and control assembly between a three-phase bus and the ground in a neutral-point small grounding mode power grid. When single-phase grounding fault happens to the power grid, the power electron commutation assembly generates current, resistive current passing through a grounding point is close to a certain set value, a relay protection device is started to cut off a fault line and the grounding point, a grounding arc can be prevented from being generated for a long time, and a neutral-point grounding transformer and a grounding resistor are replaced.
Description
Technical field
The present invention relates to technical field of electric power, relate to a kind of neutral point of electric network ground connection active pull-up method specifically.
Background technology
Three-phase ac power system neutral, the i.e. transformer of Y-connection and the neutral point of motor, and the electric connecting mode between the earth, be called Power Network Neutral.Neutral grounding mode relates to security reliability, the economy of electrical network, directly affects the selection of apparatus insulated level, system overvoltage level and the means of relay protection, communication interference etc.
110kV and above electrical network generally adopt big current earthing mode, i.e. neutral point effective grounding mode, and such neutral point potential is fixed as earth potential, and when there is single phase ground fault, healthy phases voltage raises and can not run phase voltage more than 1.4 times; Temporary overvoltage level is also lower; Fault current is very large, and relaying protection can action be in tripping operation rapidly, and excision fault, it is shorter that system equipment bears the overvoltage time.In actual motion, for reducing single-phase-to-ground current, some transformers adopts earth-free mode.
3 ~ 66 kV power distribution networks generally adopt small current neutral grounding mode, isolated neutral or the three-phase system through arc suppression coil and high resistance grounding, when a certain earth fault of generation mutually, due to can not short-circuit loop be formed, earth fault current is often much smaller than load current, i.e. neutral non-effective grounding mode.This mode electrical network allows band single phase ground fault to run in short-term, and power supply quality is better.It is generally acknowledged in China
system belongs to small current neutral grounding system power network, the U.S. and West Europe generally handle
system belong to small current neutral grounding system.
Neutral point small current neutral grounding mode mainly can be divided into following three kinds: earth-free, through grounding through arc and resistance grounded.If regulation 35kV electrical network unbalanced earth fault capacitance current is greater than 10A in China's electric equipment design specification, if 3kV ~ 10kV electrical network earthing capacitance current is greater than 30A, all need to adopt neutral by arc extinction coil grounding mode.Along with the development of supply network, particularly adopt the user of cable line day by day to increase, electric capacity and current with single-phase earthing in system is constantly increased, the possibility causing single phase ground fault in electrical network to develop into accident increases.In order to avoid single phase ground fault expands; power distribution network adopts Neutral Grounding through Resistance in Electrical mode; coordinate relaying protection to excise faulty line fast day by day to increase; " 35kV, 10kV city net; when cable line is longer, system capacitive current is larger, also can adopt resistance mode " is specified in the 59th article, China's " urban power network planning Guidance Rule " (execution).
Neutral Grounding through Resistance in Electrical connects to access resistor between neutral point of electric network with the earth; when there is single phase ground fault, line-to-ground point produces larger zero-sequence current, and zero-sequenceprotection acts on tripping operation; excision faulty line and fault point, quick recovery system normal operating condition.The resistance of suitable selection grounding resistor, the energy of half-wave after single-phase earthing electric arc of can releasing, reduces the possibility of arc reignition, suppresses power network overvoltage, improve the sensitivity of protective relaying device, thus available protecting system is normally run.This earthing mode makes the tripping operation number of times of circuit increase, affect the normal power supply of user, the reliability decrease of customer power supply, but there is stand-by power supply particularly with in the electrical network of cable power supply, the reliability service of whole electrical network can be ensured, apply increasingly extensive, particularly the industrial park of Europe and China.
Neutral resistor grounding system generally adopts the grounding transformer access electrical network of star or zigzag star connection, resistor access grounding transformer neutral point, resistor needs the electric current and voltage bearing earth fault in short-term, should have corresponding capacity and heat dissipation element, resistance box needs specialized designs manufacture.
Summary of the invention
The invention provides a kind of power electronic technology being applicable to 3 ~ 66kV power network, being easy to realization, the advanced method of power network single phase ground fault Quick for the constant current in resistance property of earth point can be realized, substitute existing neutral resistor grounding technology.Can supply earth point current in resistance property by Quick after power network generation single phase ground fault, and keep current constant, thus start relaying protection tripping operation fast, excision faulty line, to reduce arcing time restriction system overvoltage.
The technical scheme that technical solution problem of the present invention is taked is: between the three-phase bus and ground network of the power network of isolated neutral, arrange three-phase four-arm power electronics change of current assembly and corresponding detection components, generation that control assembly is grounded a current in resistance property.
A kind of power network neutral point active pull-up earthing method of the present invention specifically comprises following content: detection components monitoring network voltage curent change; when judging power network generation single phase ground fault; control power electronics change of current assembly to exporting constant current in resistance property between fault phase and ground; earth point current in resistance property is provided; thus make protective relaying device starting tripping; excision faulty line and earth point, substitute neutral grounded transformer and earth resistance.Be equivalent to increase exchanges constant-current source between ground connection phase and ground, constant-current source energy source is in power network.
Compared with prior art the beneficial effect of the inventive method is:
1, play power electronics assembly and adjust feature fast, Quick is for ground connection current in resistance property.
2, by earth point current feedback, make by the electric current of earth point close to constant, constant earth current can make this circuit relay protection sensitivity improve, and ensures relaying protection correct operation.
3, static electric power reliability of electronic equipment is higher, installs simple, easy modularization.
4, reduce the wastage, improve utilization rate of equipment and installations.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of power network active pull-up earthing method.
Fig. 2 is the circuit diagram of power network active pull-up earthing method.
Fig. 3 is the isoboles of power network active pull-up earthing method.
Fig. 4 is the control chart of power network active pull-up earthing method.
Embodiment
Below in conjunction with accompanying drawing, the present invention is further described.
Power network neutral point active pull-up earthing method of the present invention, can be applied in 3 ~ 66kV power network, is used to provide the constant current in resistance property of earth point after single phase ground fault, realizes the function of excision faulty line fast.
Its specific implementation process is:
1. determine active resistance circuit structure
Owing to provide in 3 ~ 66kV power network current in resistance property over the ground to need to produce the zero-sequence current to ground network, and adjustable in the amplitude of electric current, phase place, frequency requirement certain limit.In the inventive method, three-phase four-arm structure power electronics change of current assembly general DC busbar, four brachium pontis outputs connect three-phase bus and ground network respectively, and high frequency wholly-controled device selected by power electronics change of current device.
(1) power electronics change of current assembly
In the present invention, described three-phase four-arm power electronics change of current assembly should select high frequency wholly-controled device.Selectable high frequency wholly-controled device comprises the devices such as IGBT, IGCT, GTO, MOSFET.
As shown in Figure 2, entirely control device IGBT for voltage-type and form change of current assembly, this assembly can produce the electric current of random waveform, and can realize needs power frequency constant current, to compensate the unsteadiness of arc resistance and system voltage.
The capacity of three-phase four-arm power electronics change of current assembly should meet the requirement of ground connection current in resistance property size, generally selects between 10 ~ 1000A, and particular capacity depends on configuration and the sensitivity requirement of relaying protection system.
(2) active pull-up ground connection principle during single-phase earthing
As shown in Figure 3, for A phase circuit metallic earthing, detection components detects that A phase voltage is zero, control assembly sends instruction, control A phase and the inversion of ground connection brachium pontis, the rectification of B, C two-phase brachium pontis runs, and produces A relatively resistive power current, inversion energy takes from electrical network, is supplied to DC bus by B, C two-phase brachium pontis.
As shown in Figure 1, A phase and ground connection brachium pontis can be equivalent to constant-current source, make by the electric current of A phase earth point close to a certain set point.
2. power network state recognition
Operationally, Real-Time Monitoring electrical network three-phase voltage, electric current, judge electric network state according to electric current and voltage change to power network capacitance current active compensation equipment.
When power network normally runs, due to three relatively parameter unbalances, do not replace as three-phase line or replace not exclusively etc., the system three phase-to-ground voltage non-equilibrium state caused can occur with residual voltage simultaneously, and voltage unbalance factor is substantially identical in system.And the unbalance voltage that the uneven reactive current caused by system asymmetric load etc. produces can not occur with residual voltage.
During single phase ground fault, different according to fault point transition resistance, power network neutral point voltage (residual voltage) changes between 0 to phase voltage.
According to above-mentioned electric current and voltage feature, can recognition system status.
3. determine the control procedure of active earth resistance
It is constant that content of the present invention needs to control current in resistance property, and control section needs to increase zero sequence voltage detection and feedback control element, develops new detection control algorithm.
A kind of control program as shown in Figure 4, illustrates active ground connection control principle with A phase ground connection.
Bus-bar potential transformer 1 is connected to system busbar 9, and three-phase brachium pontis 11,12,13 is connected to bus 9, and ground connection brachium pontis 10 connects ground network 0.Definite value input unit 5 can according to zero-sequence current protection definite value setting earth current value.
By the three-phase voltage that voltage transformer 1 provides, grounding of network detection components 2 judges that system is normal, PT breaks or single-phase earthing, automatic resetting when electrical network is normal, artificial involution after PT break alarm.After single-phase earthing being detected, send alarm signal, ground connection phase selection and voltage synthesis unit 4 synthesize Earth Phase voltage U an for inversion earth current provides phase angle, add earth current instrument transformer 8 between ground connection brachium pontis 10 and ground network 0 and detect grounding reverse supply current, definite value input unit 5 sets earth current value, above three kinds of signals by comparator 6 control PWM device 7 export driving pulse control four brachium pontis 10,11,12 and 13 run.Meanwhile, ground connection phase selection and voltage synthesis unit 4 are selected fault phase and are provided phase selection signal, locking B phase brachium pontis 12 and C phase brachium pontis 13 driving pulse, and B phase and C phase brachium pontis form full-bridge rectification, directly provide DC bus power supply from electrical network; Drive A phase brachium pontis 11 and ground connection brachium pontis 10 to form full-bridge inverting, fault point current in resistance property is provided.Add feedback current by comparator 6, overcome fault point earth resistance impact, ensure that earth current is constant, improve zero-sequenceprotection action accuracy.
In Fig. 4, current waveform is desirable compensation power frequency electric capacitance current, with A phase voltage phase place for reference phase.
If other phase ground connection, provide different Earth Phase voltage and phase selection to export by unit 4, different phase brachium pontis output resistance earth currents can be controlled easily.
Claims (9)
1. a power network neutral point active pull-up earthing method; it is characterized in that; between the three-phase bus and the earth of power network, install three-phase four-arm power electronics change of current assembly and corresponding to detect, control assembly to produce earth point current in resistance property, zero-sequenceprotection starting current is provided.
2. according to power network neutral point active pull-up earthing method according to claim 1, it is characterized in that, when judging power network generation single phase ground fault, by controlling power electronics change of current assembly to exporting constant current in resistance property between fault phase and ground, substitute neutral grounded transformer and earth resistance.
3. according to power network neutral point active pull-up earthing method according to claim 2; it is characterized in that; specific implementation process is: detect network voltage curent change; when judging power network generation single phase ground fault; the current in resistance property controlling the generation of power electronics assembly default is supplied to earth point; make by the electric current of earth point close to constant, thus make zero sequence protective relaying device starting tripping, fast excision faulty line and earth point.
4. according to the power network neutral point active pull-up earthing method described in claim 1,2 or 3, it is characterized in that, described three-phase four-arm power electronics change of current assembly general DC busbar, four brachium pontis connect three-phase bus and ground network respectively.
5. according to power network neutral point active pull-up earthing method according to claim 4, it is characterized in that, high frequency wholly-controled device selected by described power electronics change of current device.
6. according to power network neutral point active pull-up earthing method according to claim 5, it is characterized in that, the capacity of described three-phase four-arm power electronics change of current assembly meets the requirement of earth point tripping current.
7. according to power network neutral point active pull-up earthing method according to claim 5, it is characterized in that, the principle realizing active pull-up ground connection is: for A phase circuit metallic earthing, detection components detects that A phase voltage is zero, and control assembly sends instruction, control A phase and the inversion of ground connection brachium pontis, the rectification of B, C two-phase brachium pontis runs, produce A relatively resistive power current, inversion energy takes from electrical network, is supplied to DC bus by B, C two-phase brachium pontis.
8., according to power network neutral point active pull-up earthing method according to claim 5, it is characterized in that, a kind of control program of described active pull-up earthing method is:
Bus-bar potential transformer (1) is connected to system busbar (9), and three-phase brachium pontis (11), (12), (13) are connected to bus (9), and ground connection brachium pontis (10) connects ground network (0); Definite value input unit (5) is according to zero-sequence current protection definite value setting earth current value;
By the three-phase voltage that voltage transformer (1) provides, grounding of network detection components (2) judges that system is normal, PT breaks or single-phase earthing, automatic resetting when electrical network is normal, artificial involution after PT break alarm; After single-phase earthing being detected, send alarm signal, ground connection phase selection and voltage synthesis unit (4) synthesis Earth Phase voltage U an provide phase angle for inversion earth current, add earth current instrument transformer (8) between ground connection brachium pontis (10) and ground network (0) and detect grounding reverse supply current, definite value input unit (5) setting earth current value; Above three kinds of signals control PWM device (7) output driving pulse by comparator (6) and control four brachium pontis (10), (11), (12) and (13) operation; Meanwhile, ground connection phase selection and voltage synthesis unit (4) select fault phase provides phase selection signal, locking B phase brachium pontis (12) and C phase brachium pontis (13) driving pulse, and B phase and C phase brachium pontis form full-bridge rectification, directly provide DC bus power supply from electrical network; Drive A phase brachium pontis (11) and ground connection brachium pontis (10) composition full-bridge inverting, fault point current in resistance property is provided; Add feedback current by comparator (6), overcome fault point earth resistance impact, ensure that earth current is constant, improve zero-sequenceprotection action accuracy.
9., according to power network neutral point active pull-up earthing method according to claim 1, it is characterized in that, described power network refers to 3 ~ 66kV power network.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310550579.4A CN104638635B (en) | 2013-11-08 | 2013-11-08 | Power network neutral point active pull-up earthing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310550579.4A CN104638635B (en) | 2013-11-08 | 2013-11-08 | Power network neutral point active pull-up earthing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104638635A true CN104638635A (en) | 2015-05-20 |
| CN104638635B CN104638635B (en) | 2018-04-10 |
Family
ID=53217086
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310550579.4A Active CN104638635B (en) | 2013-11-08 | 2013-11-08 | Power network neutral point active pull-up earthing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104638635B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105244765A (en) * | 2015-09-29 | 2016-01-13 | 中国电子科技集团公司第四十一研究所 | Active grounding system |
| CN106786682A (en) * | 2017-02-13 | 2017-05-31 | 云南电网有限责任公司电力科学研究院 | The active suppressing method and device of power distribution network imbalance of three-phase voltage |
| CN106786471A (en) * | 2015-11-20 | 2017-05-31 | 中国石油化工股份有限公司 | A kind of unidirectional active power compensator of power network neutral point isolated neutral system |
| CN106786470A (en) * | 2015-11-19 | 2017-05-31 | 中国石油化工股份有限公司 | A kind of power network neutral point flexible ground system |
| CN107894543A (en) * | 2017-11-14 | 2018-04-10 | 云南电网有限责任公司电力科学研究院 | A kind of power distribution network parameter measuring apparatus, method and system over the ground |
| CN109030953A (en) * | 2018-08-29 | 2018-12-18 | 天津市海诺电子有限公司 | A kind of busbar grounding detection protection circuit |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201038753Y (en) * | 2007-05-10 | 2008-03-19 | 济南大学 | Stable state zero-sequence current boosting device |
| JP2011002297A (en) * | 2009-06-17 | 2011-01-06 | Mitsubishi Electric Corp | Residual magnetic flux measuring device, residual magnetic flux measuring method, and synchronous switching controller of circuit breaker |
-
2013
- 2013-11-08 CN CN201310550579.4A patent/CN104638635B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201038753Y (en) * | 2007-05-10 | 2008-03-19 | 济南大学 | Stable state zero-sequence current boosting device |
| JP2011002297A (en) * | 2009-06-17 | 2011-01-06 | Mitsubishi Electric Corp | Residual magnetic flux measuring device, residual magnetic flux measuring method, and synchronous switching controller of circuit breaker |
Non-Patent Citations (1)
| Title |
|---|
| 周林: "输电线路非全相运行时负序零序电流的补偿控制研究", 《万方学位论文》 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105244765A (en) * | 2015-09-29 | 2016-01-13 | 中国电子科技集团公司第四十一研究所 | Active grounding system |
| CN106786470A (en) * | 2015-11-19 | 2017-05-31 | 中国石油化工股份有限公司 | A kind of power network neutral point flexible ground system |
| CN106786471A (en) * | 2015-11-20 | 2017-05-31 | 中国石油化工股份有限公司 | A kind of unidirectional active power compensator of power network neutral point isolated neutral system |
| CN106786682A (en) * | 2017-02-13 | 2017-05-31 | 云南电网有限责任公司电力科学研究院 | The active suppressing method and device of power distribution network imbalance of three-phase voltage |
| CN107894543A (en) * | 2017-11-14 | 2018-04-10 | 云南电网有限责任公司电力科学研究院 | A kind of power distribution network parameter measuring apparatus, method and system over the ground |
| CN109030953A (en) * | 2018-08-29 | 2018-12-18 | 天津市海诺电子有限公司 | A kind of busbar grounding detection protection circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104638635B (en) | 2018-04-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Suonan et al. | A novel UHV/EHV transmission-line pilot protection based on fault component integrated impedance | |
| CN104638630B (en) | The New Method of Active Electronic Compensation of power network capacitive earth current | |
| Saleh et al. | Impacts of grounding configurations on responses of ground protective relays for DFIG-based WECSs—Part I: solid ground faults | |
| CN104638635A (en) | Power grid neutral point active resistor grounding method | |
| CN107276082B (en) | Active voltage reduction safe operation method for ground fault phase of non-effective grounding system | |
| Guo et al. | Fault phase selection method based on single-phase flexible arc suppression device for asymmetric distribution networks | |
| CN107979080B (en) | Method and device for determining rated voltage of lightning arrester along half-wavelength power transmission line | |
| CN104779602A (en) | Flexible control method of zero-sequence voltage of resonant earthed system based on active inversion | |
| CN106786470B (en) | Flexible grounding system for neutral point of power grid | |
| Li et al. | Impact research of inductive FCL on the rate of rise of recovery voltage with circuit breakers | |
| Ma et al. | Active voltage-type arc suppression device for single-line-to-ground fault in distribution networks with consideration of line impedance | |
| CN201004553Y (en) | Arc over voltage limit for power transmission and distribution system and integrated device for small current grounding and line selection | |
| Varetsky et al. | Study of transient overvoltages on CSI adjustable speed drives under arcing SLGF in the industrial cable grid | |
| CN113452014B (en) | Accurate and rapid suppression method for unbalanced zero sequence voltage of power distribution network | |
| Varetsky | Overvoltages in MV industrial grid under ground faults | |
| Li et al. | Research on DC component decay time constant of 1000 kV AC filter circuit breakers in UHV converter station | |
| CN103490384B (en) | Multi-generator ship intermediate voltage electric power system protection method and device | |
| Hussein et al. | Mitigation of adverse effects of gics on transformers using look-up table controlled ground resistance | |
| Zhen-xin et al. | Effects of series reactor on short-circuit current and transient recovery voltage | |
| CN114264942B (en) | Calculation method for generating selection-related voltage and current waveforms of high-voltage alternating current circuit breaker | |
| CN115693630B (en) | Hybrid arc extinguishing system based on split winding and working method thereof | |
| CN203434496U (en) | Current grounding system for wind farm | |
| Van Cutsem | Introduction to balanced fault analysis | |
| Meng et al. | Application of 66kV active intervention grounding arc suppression device | |
| CN212412739U (en) | Novel fault management control device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230822 Address after: 100728 No. 22 North Main Street, Chaoyang District, Beijing, Chaoyangmen Patentee after: CHINA PETROLEUM & CHEMICAL Corp. Patentee after: Sinopec (Dalian) Petrochemical Research Institute Co.,Ltd. Address before: 100728 No. 22 North Main Street, Chaoyang District, Beijing, Chaoyangmen Patentee before: CHINA PETROLEUM & CHEMICAL Corp. Patentee before: DALIAN RESEARCH INSTITUTE OF PETROLEUM AND PETROCHEMICALS, SINOPEC Corp. |