CN207705796U - A kind of multifunctional ligand power grid flexible ground device - Google Patents
A kind of multifunctional ligand power grid flexible ground device Download PDFInfo
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- CN207705796U CN207705796U CN201820038619.5U CN201820038619U CN207705796U CN 207705796 U CN207705796 U CN 207705796U CN 201820038619 U CN201820038619 U CN 201820038619U CN 207705796 U CN207705796 U CN 207705796U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E40/30—Reactive power compensation
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Abstract
The utility model discloses a kind of multifunctional ligand power grid flexible ground devices, the device is set to generator side, power distribution network Circuit Fault on Secondary Transformer or power distribution network bus bar side, the device includes 3-phase power converter and controllable switch, and 3-phase power converter neutral point can be grounded by controllable switch；Device is operated in reactive-load compensation pattern under normal circumstances, when singlephase earth fault occurs for power distribution network, controllable switch is closed, device injects zero sequence/common mode current or zero sequence/common-mode voltage into power distribution network three-phase line to achieve the purpose that singlephase earth fault extinguishing arc and fault location, and reactive-load compensation, singlephase earth fault extinguishing arc and fault location function can be carried out at the same time.The functions such as reactive-load compensation, line-to-ground parameter measurement, extinguishing arc, failure line selection positioning are integrated in same device by the utility model, and it can really realize machine multiplexing with the normal operation of the no-power compensation function of holding meanss while realizing the functions such as single-phase earthing extinguishing arc, single-phase earthing point route selection and positioning.
Description
Technical field
The reactive-load compensation of the utility model category power industry more particularly to three-phase isolated neutral system power distribution network, line
Road Parameter Measuring, singlephase earth fault extinguishing arc, single-phase earthing point route selection positioning field over the ground, specially a kind of multifunctional ligand
Power grid flexible earthing or grounding means.
Background technology
Domestic medium voltage distribution network mostly uses greatly the method for operation of isolated neutral, due to the development in city, city power distribution
Net constantly expands, and power cable usage amount is continuously increased, and distribution line direct-to-ground capacitance increasingly increases, when power distribution network generation is single-phase
When earth fault, easily cause seriously to earth-current.Distribution network line capacitive earth current is to influence distribution network planning design and fortune
The important parameter of row safety.The size of capacitance current not only has decided on whether the benefit for needing to install arc suppression coil and arc suppression coil
Capacity is repaid, and power distribution network needs to carry out switching to different circuits in the process of running, therefore line-to-ground parameter is real-time
On-line measurement is particularly important.The measurement of capacitor current for earthing is broadly divided into method of engineering calculation, direct method and indirect method.
Method of engineering calculation carries out theoretical calculation according to parameters such as the length of circuit to direct-to-ground capacitance, is generally used for assessment new construction, meter
It is larger to calculate error, is only used for referring to.Direct method also becomes metallic ground method, and the method directly operates a circuit,
It is easy to bring safety issue to survey crew.General line-to-ground parameter measurement uses indirect method, and the letter in indirect method
Number injection method is widely used due to its safe operation.But signal injection method be by PT or arc suppression coil to
Power distribution network injects measuring signal, on the one hand can be influenced by transformer leakage impedance, on the other hand pass through the transformer of high no-load voltage ratio
The Injection Signal in power distribution network can be caused to decay excessive, it is difficult to accurate to measure.
When singlephase earth fault occurs for medium voltage distribution network, since earth point fault current is larger, electric arc is difficult to voluntarily put out
It goes out, if timely and effective inhibition cannot be obtained, easily develops into permanent singlephase earth fault, thereby increases and it is possible to cause more than 3 times phase voltages
System overvoltage, lead to sound mutually insulation weak link breakdown, cause phase fault.So the event of power distribution network single-phase earthing point
It is accurate and quick to hinder current compensation needs, the further development of arc light could be inhibited in time in this way.Present the single-phase of power distribution network connects
The method of extinguishing arc is broadly divided into two kinds of voltage extinguishing arc and electric current extinguishing arc in earth fault.Voltage extinguishing arc method is exactly by controlling failure phase
Restore voltage, it is zero or too late dielectric breakdown voltage so that failure is mutually restored voltage, to realize arc extinguishing.Traditional " arc extinction cabinet "
Applied voltage extinguishing arc principle, using circuit breaker short circuit earth fault phase, the method for clamping down on faulted phase voltage prevents fault electric arc weight
Combustion.But it is restricted by high resistance earthing fault phase selection precision is low, in fact it could happen that mistake phase selection, short circuit non-faulting phase problem, while by
It is limited to breaker acting speed, switching the electric arc of several ms before short circuit cannot effectively control, and short circuit bypass dash current is big, can
The current potential of substation can be interfered.Electric current extinguishing arc method reduces dielectric damages and mutually restores electricity with failure using residue current of ground fault in electrical is inhibited
The method of the rate of climb of pressure promotes failure extinguishing arc.Arc suppression coil promotes electric arc because it is with effective compensation fault capacitance electric current
The advantages of quickly extinguishing, is used widely in power distribution network.But the active loss of arc suppression coil increases earth fault electricity
The active component of stream, and its adjustment is difficult, cumbersome, tuning-off degree measures difficulty, and tuning is improper to be also easy to produce resonance overvoltage.
The frequency that singlephase earth fault occurs in medium voltage distribution network is high, when singlephase earth fault occurs, will not be formed
Short-circuit loop is only caused the earth-fault current of very little, system that can continue to run with by the distribution capacity of system.But single-phase event
When barrier ground connection, non-faulting phase-to-ground voltage increases, and overvoltage may cause earth fault to be converted into phase fault, serious to endanger
Evil system insulation and equipment safety.For system safety operation, power supply reliability, reduction loss of outage are improved, is needed single-phase
Faulty line and position of failure point are determined after earth fault rapidly, further to take troubleshooting measure.To single-phase earthing
The localization method of the fault point of failure is broadly divided into two classes, active localization method and passive type localization method.Active failure
Localization method is to inject signal specific to system after line failure, by detecting the distribution of institute's Injection Signal in systems
Determine position of failure point.Passive type Fault Locating Method is then the feature of voltage and current signal produced by utilizing failure itself,
Design Orientation algorithm, determines position of failure point.Active Fault Locating Method is broadly divided into zero-sequence current mutation method, middle resistance again
Method, transfer function method, signal injection method.Zero-sequence current mutation method is to generate zero-sequence current mutation by changing arc suppression coil parameter
Amount realizes positioning, is influenced by jitterbug, and changes arc suppression coil parameter and be unfavorable for system safety.Middle electric-resistivity method is in event
Barrier artificially puts into a medium resistance between property point and ground in systems after occurring, and detects additional power frequency fault current distribution, should
Method artificially increases earth current, increases system security risk, and medium resistance difficult design.Transfer function method be
Failure exit applies a kind of method of single end distance measurement of the square wave diagnostic signal according to the frequency spectrum of transmission function, due to distribution network parameters
Complexity, this method are only feasible in theory, it is difficult to practical application.Generally signal injects in active Fault Locating Method
Method is widely applied since it avoids the vulnerability to jamming of faults itself signal.Signal injection method generally utilizes signal
Injection device injects specific current signal by busbar PT to system, and there is limited by PT capacity for common AC signal injection
System and the current signal in system fainter the problems such as being difficult to detect, is transmitted to by PT.
The shortcomings that above-mentioned parameter measurement over the ground, extinguishing arc, the method for line selection and location not only are difficult to overcome in itself, and it is each
Kind function is required for specific protective device, causes distribution network system protective device complicated, and management is inconvenient, protection and detection device
The problems such as utilization rate is low.On the other hand, the flexible ground device based on power electronic devices is typically mounted at power network neutral point
Place only just works when singlephase earth fault occurs for distribution network line, and without other additional functions, capacity utilization is relatively low.
Utility model content
In consideration of it, the purpose of this utility model is to provide a kind of multifunctional ligand power grid flexible ground device.The device is in day
Often reactive-load compensation and line-to-ground parameter measurement are realized when operation；Realize that extinguishing arc, single-phase earthing are clicked in singlephase earth fault
Reactive-load compensation normal operation is kept while line and positioning function.
The purpose of this utility model is achieved through the following technical solutions, a kind of multifunctional ligand power grid flexible ground dress
It sets, which is set to generator side, power distribution network Circuit Fault on Secondary Transformer or power distribution network bus bar side, which includes 3-phase power converter
And controllable switch, the 3-phase power converter access generator side, power distribution network Circuit Fault on Secondary Transformer or power distribution network bus bar side, described three
Phase current transformer neutral point is grounded by controllable switch；
Described device is operated in reactive-load compensation pattern under normal circumstances, and time closing controllable switch measures pair of circuit
Ground parameter；
When singlephase earth fault occurs for power distribution network, the controllable switch is closed, and device is noted into power distribution network three-phase line
Enter zero sequence/common mode current or zero sequence/common-mode voltage is used for singlephase earth fault extinguishing arc and fault location, and reactive-load compensation, list
Phase earth fault extinguishing arc and fault location function can be carried out at the same time.
Further, the 3-phase power converter be two level three-phase half-bridges, three-level three-phase half-bridge, more level three-phase half-bridges or
Three-phase tandem type H bridges.
Further, the 3-phase power converter is the 3-phase power converter of high pressure level, directly hangs over 10kV or 35kV voltages etc.
On the power distribution network busbar of grade.
Further, the 3-phase power converter is the 3-phase power converter of low pressure grade, and the 3-phase power converter is become by boosting
Depressor is connected on the power distribution network busbar of 10kV or 35kV voltage class.
By adopting the above-described technical solution, the utility model has the following advantages：
General power distribution network usually requires to be equipped with reactive-load compensation, over the ground a series of dresses such as parameter measurement, extinguishing arc, line selection and location
It sets, causes distribution network system protective device complicated, management is inconvenient, protects the problems such as low with detection device utilization rate, is asked for this
Topic, the utility model proposes a kind of with reactive-load compensation, the function integrations such as parameter measurement, extinguishing arc, line selection and location is new over the ground
Type multifunctional electric power distribution network device can realize line-to-ground parameter measurement, single-phase earthing extinguishing arc, single-phase earthing point
No-power compensation function is realized while the functions such as route selection and positioning.Really realize the machine multiplexing of common reactive power compensator, and
And each additional function and the mutual Lothrus apterus of no-power compensation function.
Description of the drawings
In order to keep the purpose of this utility model, technical solution and advantage clearer, below in conjunction with attached drawing to this practicality
It is novel to be described in further detail, wherein：
Fig. 1 is power distribution network and multi-function device topological diagram；
Fig. 2 is using cascaded H-bridges as the multi-function device structural schematic diagram of embodiment；
Fig. 3 is using two-level inverter and step-up transformer as the multi-function device structural schematic diagram of embodiment；
Fig. 4 is to measure line mutual-ground capacitor equivalent circuit；
Fig. 5 is the fault detector arrangement schematic diagram positioned for one-phase earthing failure in electric distribution network.
Specific implementation mode
Below with reference to attached drawing, the preferred embodiment of the utility model is described in detail；It should be appreciated that preferably real
Example is applied only for illustrating the utility model, rather than in order to limit the scope of protection of the utility model.
Fig. 1 is power distribution network and multi-function device topological diagram；Fig. 2 is using cascaded H-bridges as the multi-function device structure of embodiment
Schematic diagram；Fig. 3 is using two-level inverter and step-up transformer as the multi-function device structural schematic diagram of embodiment；Fig. 4 is to survey
Measure line mutual-ground capacitor equivalent circuit；Fig. 5 is the fault detector arrangement schematic diagram positioned for one-phase earthing failure in electric distribution network.
First, in Fig. 1 it is typical distribution network line, distribution network line includes line-to-ground parameter and measurement line-to-ground
The voltage transformer of voltage.3-phase power converter 12 in figure is cascaded H-bridges shown in Fig. 2 topology or is two electricity shown in Fig. 3
The form of the flat boosted transformer boosting of inverter, the neutral point of 3-phase power converter 12 can be grounded by controllable switch 13.
As shown in Figure 1, a kind of multifunctional electric power distribution network device, the device are set to power distribution network Circuit Fault on Secondary Transformer
(power distribution network bus bar side), the device include 3-phase power converter 12, and the neutral point of the 3-phase power converter 12 can pass through controllable switch
13 ground connection.
In the present embodiment, controllable switch 13 is contactor S1.
The utility model has reactive-load compensation, over the ground parameter measurement, circuit single-line ground extinguishing arc, circuit single-line ground route selection
The functions such as positioning can realize the functions such as line-to-ground parameter measurement, single-phase earthing extinguishing arc, single-phase earthing point route selection and positioning
While realization device no-power compensation function, be truly realized a machine multiplexing, each additional function and no-power compensation function are mutual
Lothrus apterus.
The operation principle of each function addressed below：
Reactive-load compensation pattern：When device operates in reactive-load compensation pattern, contactor S1 is disconnected, and the control method of device is
Dq Uncoupling Control Baseds based on synchronous rotating frame..
Line-to-ground parameter measurement pattern：Contactor S1 is connected, device can be injected to distribution network system certain amplitude and
Zero sequence (common mode) voltage of frequency, passes through the measurement of corresponding zero sequence (common mode) electric current, you can online accurately calculate is matched this moment
The direct-to-ground capacitance of power network line.
Arc light eliminates pattern：Increase can also be passed through to eliminate the earth current of arc grounding point by connecting contactor S1
Zero sequence (common mode) control access, device inject power frequency zero sequence (common mode) electric current of certain amplitude, common mode current to distribution network system
Two non-faulting compatibility electric currents can be offset and intercept, as shown in Figure 1, so as to compensate the fault current of earth point.
The reference instruction of specific zero sequence (common mode) electric current can be obtained from the measurement of line-to-ground parameter.
Route selection and earth point station-keeping mode：Connect contactor S1, by increase zero sequence (common mode) control access, device to
Network system injects zero sequence (common mode) character voltage or electric current of certain amplitude and frequency, is examined on three-phase line by comparing analyzing
The amplitude size of this feature signal measured, failure judgement circuit are detected further according to the detection device of installation on the line
The feedback of the signal then determines the position of fault point.
In conclusion the core of the utility model is based on distribution network var compensation device, it is added in dq algorithms
The control of zero sequence (common mode) component, to realize reactive-load compensation, over the ground parameter measurement, circuit single-line ground extinguishing arc, circuit single line
A series of functions such as earthing wire-selecting positioning integrate.
The multifunctional assembling in the form of cascaded H-bridges is set to embodiment and is described in detail below.
1, line-to-ground parameter measurement
Before measuring line-to-ground parameter, contactor S1 is closed first, zero sequence (common mode) control access is closed, and
Set U0=Asin (ωnT), multi-function device will inject zero sequence (common mode) voltage U into distribution network line0, U0Frequency range
It is traditionally arranged to be 20~90Hz, zero sequence (common mode) equivalent circuit of distribution network line is as shown in figure 4, zero sequence (common mode) electric current at this time
I0It can be by current sensor measurement, since the impedance of voltage transformer is generally very big, so voltage transformer branch one
As can be ignored.According to U0、I0Value can obtain distribution network line total capacitance value over the ground by Fig. 4.Since output filters
Device inductance value is smaller, generally can be ignored.
2, circuit single-phase earthing arc light inhibits (extinguishing arc)
When singlephase earth fault occurs for circuit, as shown in Figure 1：C phase lines are grounded.In order to inhibit arc grounding phenomenon
Occur, it is 0 to need the current control for flowing through earth point, in order to realize this target, is first closed contactor S1, then will
Zero sequence (common mode) control access is closed, and I is then arranged0ref=j ω0CgroundUc。
By the closed-loop control of zero sequence (common mode) control access may be implemented by the current control of earth point be close to 0, from
And inhibit the generation of arc grounding.
3, the point route selection of circuit single-phase earthing and positioning
When singlephase earth fault occurs for circuit, as shown in Figure 1：C phase lines are grounded.In order to be grounded circuit as early as possible
The positioning of selection and earth point, can be injected a certain amount of characteristic quantity into system by multi-function device, be fitted to circuit
On fault detector the route selection and positioning of circuit single-phase earthing point may be implemented.
After singlephase earth fault occurs, contactor S1 is closed, and is then closed zero sequence (common mode) control access and is disappeared
Arc sets U when crowbar currents fail to eliminate singlephase earth fault0=Asin (ωnT), U0Frequency range be traditionally arranged to be
100~200Hz, at this point, zero sequence (common mode) voltage and current, each indicating fault in Fig. 5 will be generated in distribution network line
Device can detect characteristic component (the angular frequency ω of the injection in the three-phase current of the pointn), usually in the electric current of generation Earth Phase
Characteristic component it is larger, may thereby determine that it is which phase line is grounded.It is which phase line is grounded in determination
Later, it is assumed herein that being that C phases are grounded, then are compared in Fig. 5 detected by the C phase detectors of 1 to No. 11 fault detector
Characteristic component value size, C phases earth point as shown in Figure 5 between No. 5 and No. 6 fault detectors, then No. 5 finger
Show that the characteristic component of C phase currents in device is larger, and in No. 6 indicators C phase currents characteristic component very little, then i.e. explainable spy
Sign current component is shunted from some earth point between No. 5 and No. 6 fault detectors, it is possible to determine earth point position
Between No. 5 and No. 6 fault detectors, then it can be looked for by the circuit between No. 5 and No. 6 fault detectors of artificial line walking
To earth point specific location.
The above is only the preferred embodiment of the present invention, is not intended to limit the utility model, it is clear that this field
Technical staff spirit and scope of the various modification and variations without departing from the utility model can be carried out to the utility model.This
Sample, if these modifications and variations of the present invention belong to the claims of the present invention and its equivalent technology range it
Interior, then the utility model is also intended to include these modifications and variations.
Claims (4)
1. a kind of multifunctional ligand power grid flexible ground device, it is characterised in that：The device is set to generator side, power distribution network transformation
Device secondary side or power distribution network bus bar side, the device include 3-phase power converter and controllable switch, the 3-phase power converter access power generation
Pusher side, power distribution network Circuit Fault on Secondary Transformer or power distribution network bus bar side, the 3-phase power converter neutral point are grounded by controllable switch；
Described device is operated in reactive-load compensation pattern under normal circumstances, and time closing controllable switch measures the ginseng over the ground of circuit
Number；
When singlephase earth fault occurs for power distribution network, the controllable switch is closed, and device injects zero into power distribution network three-phase line
Sequence/common mode current or zero sequence/common-mode voltage are used for singlephase earth fault extinguishing arc and fault location, and reactive-load compensation, single-phase connect
Earth fault extinguishing arc and fault location function can be carried out at the same time.
2. a kind of multifunctional ligand power grid flexible ground device according to claim 1, it is characterised in that：The three-phase unsteady flow
Device is two level three-phase half-bridges, three-level three-phase half-bridge, more level three-phase half-bridges or three-phase tandem type H bridges.
3. a kind of multifunctional ligand power grid flexible ground device according to claim 1, it is characterised in that：The three-phase unsteady flow
Device is the 3-phase power converter of high pressure level, is directly hung on the power distribution network busbar of 10kV or 35kV voltage class.
4. a kind of multifunctional ligand power grid flexible ground device according to claim 1, it is characterised in that：The three-phase unsteady flow
Device is the 3-phase power converter of low pressure grade, and the 3-phase power converter is connected to 10kV or 35kV voltage class by step-up transformer
Power distribution network busbar on.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820038619.5U CN207705796U (en) | 2018-01-10 | 2018-01-10 | A kind of multifunctional ligand power grid flexible ground device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201820038619.5U CN207705796U (en) | 2018-01-10 | 2018-01-10 | A kind of multifunctional ligand power grid flexible ground device |
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| Publication Number | Publication Date |
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| CN207705796U true CN207705796U (en) | 2018-08-07 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108054764A (en) * | 2018-01-10 | 2018-05-18 | 重庆聚陆新能源有限公司 | A kind of multifunctional ligand power grid flexible ground device and control method |
| CN110261713A (en) * | 2019-05-05 | 2019-09-20 | 南瑞集团有限公司 | A method of diagnosis flexible direct current line commutation device exchange flanks earth fault |
| CN113178854A (en) * | 2021-04-27 | 2021-07-27 | 福州大学 | Flexible dispersion arc extinction method for power distribution network ground fault based on master-slave control |
| CN113466625A (en) * | 2021-06-30 | 2021-10-01 | 云南电网有限责任公司电力科学研究院 | Ground fault finding multiplexing system and method |
-
2018
- 2018-01-10 CN CN201820038619.5U patent/CN207705796U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108054764A (en) * | 2018-01-10 | 2018-05-18 | 重庆聚陆新能源有限公司 | A kind of multifunctional ligand power grid flexible ground device and control method |
| CN110261713A (en) * | 2019-05-05 | 2019-09-20 | 南瑞集团有限公司 | A method of diagnosis flexible direct current line commutation device exchange flanks earth fault |
| CN110261713B (en) * | 2019-05-05 | 2021-07-02 | 南瑞集团有限公司 | Method for diagnosing AC side ground fault of converter of flexible DC power grid |
| CN113178854A (en) * | 2021-04-27 | 2021-07-27 | 福州大学 | Flexible dispersion arc extinction method for power distribution network ground fault based on master-slave control |
| CN113178854B (en) * | 2021-04-27 | 2023-12-29 | 福州大学 | Flexible distributed arc extinction method for power distribution network ground fault based on master-slave control |
| CN113466625A (en) * | 2021-06-30 | 2021-10-01 | 云南电网有限责任公司电力科学研究院 | Ground fault finding multiplexing system and method |
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