CN114156906A - Multifunctional compensation method for asymmetric power distribution network - Google Patents
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
- H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
- H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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Abstract
The invention relates to a multifunctional compensation method for an asymmetric power distribution network, which takes a four-bridge arm cascade H-bridge converter without an independent direct current source as a multifunctional converter and takes sequence control as a control strategy of the multifunctional converter. The method has the advantages of high utilization rate of equipment, low implementation cost, comprehensive compensation effect and better fault suppression performance.
Description
Technical Field
The invention belongs to the field of power distribution networks, and particularly relates to a multifunctional compensation method for an asymmetric power distribution network.
Background
The flexible arc extinction of distribution network single-phase earth fault and reactive compensation converter all have the function singleness, and flexible arc extinction converter only plays a role during the trouble, and the rate of utilization is low, and the economic nature of equipment is not good enough.
At present, the existing topological structure with flexible arc extinction and reactive compensation functions mainly comprises: the neutral point of the three-phase cascade H-bridge converter is directly grounded or grounded through a switch and the neutral point of the three-phase cascade H-bridge converter is grounded through an arc suppression coil. However, when the neutral point of the three-phase cascaded H-bridge converter is directly grounded or grounded through a switch, and a low-resistance ground fault occurs, the non-fault phase voltage is close to the line voltage, and the fault phase voltage is close to zero, so that the withstand voltage of each phase converter is not lower than the line voltage, and more power electronic elements are required to be used. In addition, at this time, the voltage at two ends of the fault phase converter is close to zero, active power cannot be absorbed from a grid-connected point to maintain the voltage stability of a direct-current side capacitor, the operation must be quitted, and reactive power compensation and fault suppression can only be time-division multiplexed and cannot be carried out simultaneously. The calculation of a control object of the three-phase cascade H-bridge converter neutral point grounded through the arc suppression coil for ground fault current compensation is complex, and the ground transition resistance needs to be obtained first, but the ground transition resistance may be changed all the time during the arc ground fault, so that the obtaining is difficult. In addition, the dynamic response speed of the arc suppression coil is low, the initial arc suppression effect of the ground fault is influenced, and the three-phase cascade H-bridge converter needs to be matched with the arc suppression coil, so that the control is complex.
Disclosure of Invention
The invention aims to provide a multifunctional compensation method for an asymmetric power distribution network, which has the advantages of high equipment utilization rate, low implementation cost, comprehensive compensation effect and better fault suppression performance.
In order to achieve the purpose, the invention adopts the technical scheme that: a multifunctional compensation method for an asymmetric power distribution network takes a four-bridge-arm cascaded H-bridge converter without an independent direct current source as a multifunctional converter, and takes sequence control as a control strategy of the multifunctional converter.
Further, the multifunctional converter comprises a three-phase bridge arm adopting a three-phase H-bridge converter, the three-phase bridge arm is in star connection, and a grounding bridge arm adopting a single-phase H-bridge converter is additionally arranged between the star connection point and the ground.
Further, the three-phase H-bridge converter comprises a three-phase cascade H-bridge and a connecting inductor, wherein the three-phase cascade H-bridge comprises a two-level three-phase half bridge, a three-level three-phase half bridge, a multi-level three-phase half bridge or a three-phase cascade H-bridge; the single-phase H-bridge converter comprises a single-phase H-bridge and a connecting inductor, wherein the single-phase H-bridge comprises a two-level single-phase half bridge, a three-level single-phase half bridge, a multi-level single-phase half bridge or a single-phase cascading H-bridge; and the DC sides of the three-phase H-bridge converter and the single-phase H-bridge converter are not provided with independent DC sources.
Further, the reactive compensation current target value calculation method comprises the following steps: according to the instantaneous power theory, a given reactive power target value is converted and calculated into a q-axis target current value through abc-dq conversion, a d-axis target current value is set to be zero, and then the target current values of the d axis and the q axis are inversely converted into a reference target value calculated by three-phase reactive compensation current through dq-abc.
Further, the calculation method of the three-phase earth parameter asymmetric compensation current comprises the following steps: and controlling the zero sequence voltage of the system to be zero, measuring the output current of the grounding bridge arm of the multifunctional converter at the moment, and taking the output current as a reference target value for calculating the asymmetric current.
Further, the method for calculating the ground fault compensation current of the three-phase bridge arm converter comprises the following steps: the sum of the earth fault compensation currents of the three-phase bridge arm is always the earth fault full compensation current, namely the product of a negative value of a fault phase power supply voltage and a system ground admittance, the fault phase compensation current is the product of the negative value of the fault phase power supply voltage and a local ground admittance and a number 2, and the non-fault phase compensation current is the product of the local phase power supply voltage and the local ground admittance.
Further, the interphase control method for the direct current side capacitor voltage-stabilized current of the three-phase bridge arm converter comprises the following steps: the stabilized current on the direct current side of the three-phase bridge arm converter only circulates at the interphase and does not pass through the ground branch, namely the sum of the three-phase stabilized current is always kept zero; and the total regulated current of each phase is obtained by the difference value of one half of the regulated current of the phase and the regulated currents of other two phases.
Further, the method for calculating the ground fault compensation current of the grounding bridge arm converter comprises the following steps: the ground fault compensation current of the grounding bridge arm is the ground fault full compensation current, namely the product of the negative value of the fault phase power supply voltage and the system admittance to the ground.
Further, the method for calculating the dc-side capacitance regulated voltage of the ground bridge arm converter comprises the following steps: the output current of the grounding bridge arm is ensured to be the full compensation current of the grounding fault all the time, and the direct current side voltage stabilization of the grounding bridge arm converter adopts a mode of regulating and controlling the common point voltage of the three-phase bridge arm.
Compared with the prior art, the invention has the following beneficial effects:
1. the multifunctional converter topological structure comprising the four-bridge-arm H-bridge converter provided by the invention enables a set of converters to simultaneously have the functions of single-phase earth fault suppression, asymmetric current compensation and reactive compensation, the utilization rate of equipment is improved, the voltage borne by each phase of cascaded H-bridge converter is the phase voltage, the number of elements required to be input is small, and the economy of the equipment is better. In addition, the invention has the advantages of high dynamic response speed, no need of an independent power supply on the direct current side, capability of inhibiting the arc ground fault, capability of realizing full compensation of the ground fault current and the like.
2. The method for calculating the ground fault compensation current of the three-phase converter not only ensures the full compensation of the ground fault current, but also more uniformly distributes the direct-current side capacitor voltage stabilization current of the converter to each phase, so that the coordination performance of fault suppression and direct-current side capacitor voltage stabilization control is better, and the control complexity is lower.
3. According to the interphase control method for the stabilized voltage current of the direct current side capacitor of the converter, the stabilized voltage current does not pass through the grounding loop and only flows between the phases, the stabilized voltage current and the ground fault compensation current are decoupled, the influence of the stabilized voltage current on fault suppression is avoided, and the fault suppression performance of the multifunctional converter is better.
Drawings
Fig. 1 is a schematic view of a topology structure of a multifunctional converter in the method according to the embodiment of the present invention;
FIG. 2 illustrates a control strategy of the multi-function converter in the method of the embodiment of the present invention;
fig. 3 is a diagram illustrating the effect of multi-target control of the multifunctional converter in the method according to the embodiment of the present invention.
Detailed Description
The invention is further explained below with reference to the drawings and the embodiments.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
As shown in fig. 1 and 2, in the present embodiment, a four-leg cascaded H-bridge converter without an independent dc source is used as a multifunctional converter, so that one set of converters has the functions of single-phase ground fault suppression, asymmetric current compensation and reactive power compensation at the same time. The method takes sequence control as a control strategy of the multifunctional converter, and comprises a reactive compensation current target value calculation method, a three-phase ground parameter asymmetric compensation current calculation method, a three-phase bridge arm converter ground fault compensation current calculation method and a direct current side capacitance voltage-stabilized current interphase control method thereof, and a ground fault compensation current calculation method and a direct current side capacitance voltage-stabilized voltage calculation method thereof, so that reactive power compensation, ground fault compensation and asymmetric current compensation are realized. According to the method for calculating the ground fault compensation current of the three-phase bridge arm converter adaptive to the multifunctional converter and the interphase control method of the direct-current-side capacitor voltage stabilization current of the three-phase bridge arm converter, the direct-current-side capacitor voltage stabilization current of the converter is more uniformly distributed to each phase, the voltage stabilization current is guaranteed to only flow between phases without passing through a ground circuit, and effective cooperation of fault suppression and direct-current-side capacitor voltage stable control is achieved.
In this embodiment, the multifunctional converter includes a three-phase bridge arm using a three-phase H-bridge converter, the three-phase bridge arm is connected in a star shape, and a grounding bridge arm using a single-phase H-bridge converter is additionally arranged between the star-shaped connection point and the ground. The three-phase bridge arm is used for reactive power compensation, and the grounding bridge arm provides a circulation loop for single-phase grounding fault current and asymmetric compensation current so as to realize grounding fault current compensation and asymmetric current compensation. The three-phase H-bridge converter comprises a three-phase cascade H-bridge and a connecting inductor, wherein the three-phase cascade H-bridge comprises a two-level three-phase half bridge, a three-level three-phase half bridge, a multi-level three-phase half bridge or a three-phase cascade H-bridge; the single-phase H-bridge converter comprises a single-phase H-bridge and a connecting inductor, wherein the single-phase H-bridge comprises a two-level single-phase half bridge, a three-level single-phase half bridge, a multi-level single-phase half bridge or a single-phase cascading type H-bridge. And the DC sides of the three-phase H-bridge converter and the single-phase H-bridge converter are not provided with independent DC sources.
The reactive compensation current target value calculation method specifically comprises the following steps: according to the instantaneous power theory, a given reactive power target value is converted and calculated into a q-axis target current value through abc-dq conversion, a d-axis target current value is set to be zero, and then the target current values of the d axis and the q axis are inversely converted into a reference target value calculated by three-phase reactive compensation current through dq-abc.
The method for calculating the three-phase ground parameter asymmetric compensation current specifically comprises the following steps: and controlling the zero sequence voltage of the system to be zero, measuring the output current of the grounding bridge arm of the multifunctional converter at the moment, and taking the output current as a reference target value for calculating the asymmetric current.
The method for calculating the ground fault compensation current of the three-phase bridge arm converter specifically comprises the following steps: the sum of the earth fault compensation currents of the three-phase bridge arm is always the earth fault full compensation current, namely the product of a negative value of a fault phase power supply voltage and a system ground admittance, the fault phase compensation current is the product of the negative value of the fault phase power supply voltage and a local ground admittance and a number 2, and the non-fault phase compensation current is the product of the local phase power supply voltage and the local ground admittance.
The interphase control method of the direct current side capacitor voltage-stabilizing current of the three-phase bridge arm converter specifically comprises the following steps: the stabilized current on the direct current side of the three-phase bridge arm converter only circulates between phases and does not pass through a ground branch, namely the sum of the three-phase stabilized current is always kept zero. And the total regulated current of each phase is obtained by the difference value of one half of the regulated current of the phase and the regulated currents of other two phases.
The method for calculating the ground fault compensation current of the grounding bridge arm converter specifically comprises the following steps: the ground fault compensation current of the grounding bridge arm is the ground fault full compensation current, namely the product of the negative value of the fault phase power supply voltage and the system admittance to the ground.
The method for calculating the direct current side capacitance voltage regulation of the grounding bridge arm converter specifically comprises the following steps: the output current of the grounding bridge arm is ensured to be the full compensation current of the grounding fault all the time, and the direct current side voltage stabilization of the grounding bridge arm converter adopts a mode of regulating and controlling the common point voltage of the three-phase bridge arm.
The following is a detailed description of the relevant principles involved in the implementation of the present method:
1. principle of reactive power compensation
From the theory of instantaneous power, the instantaneous power is
And is also provided with
In the formula, T is park transformation, ua、ubAnd ucAre respectively the grid-connected three-phase voltage u of the multifunctional converterd、uqThe voltage of the grid-connected point is converted into the voltage of d axis and q axis respectively, E is the amplitude of the phase power supply voltage, omega is the angular frequency of the system, i isdAnd iqThe current transformer is injected with currents transformed to d-axis and q-axis respectively.
Substituting and arranging the parameter of T into the formula (2) to obtain
The reference current values of d-axis and q-axis during reactive compensation are obtained from the equations (1) and (3)
In the formula, P*And Q*The target values of active power compensation and reactive power compensation issued by the power dispatching department are respectively, and the multifunctional converter only carries out reactive power compensation, so that the target value of the active power compensation is set to zero.
The three-phase reactive compensation current reference value obtained by carrying out dq-abc inverse transformation on the reference current value shown in the formula (4) is
And controlling each phase current transformer to output the compensation current to realize the compensation of the reactive power.
2. Ground fault suppression
Suppose that the A phase has single-phase earth fault and three phases are symmetrical to earth parameters, and the leakage resistance to earth is r0The capacitors to ground are all C0The ground parameters and the voltage are obtained by sorting according to kirchhoff law and substitution
To make the fault point current zero, i.e. If＝(U0+Ea)/RfIs zero, EaCan be approximated to a constant value, then U0＝-EaSubstituting the fault current into the formula (6) to obtain the control target of the grounding bridge arm converter during the full compensation of the fault current
3. DC side voltage stabilization control
The dc side voltage of the converter needs to be maintained by absorbing active power from the point of connection, which is mainly related to the current flowing through the converter, the voltages at the two ends of the converter and the included angle between the two. The ground fault does not affect the normal work of the multifunctional converter in the reactive compensation mode, only the voltage of the common point and the voltage of the grid-connected point of the multifunctional converter are changed, and the voltages at two ends of the three-phase bridge arm of the multifunctional converter (namely the difference value of the voltage of the grid-connected point and the voltage of the common point) are always kept close to the voltage of a phase power supply. The invention provides a novel method for distributing earth fault compensation current in a three-phase converter, which has the specific expression of
The zero sequence current of the three-phase converter is full compensation current, and the compensation current of each phase is the product of the voltage at two ends of the phase converter and the ground parameter. The damping rate of the distribution line is generally smaller, so that the included angle between the compensation current of each phase and the voltage at two ends of the phase-change current converter is close to 90 degrees, the compensation current distributed to the fault phase and the non-fault phase is two thirds and one third of the total compensation current respectively, the active power required to be absorbed by each phase-change current converter is smaller, and the realization is easier.
The sum of the three-phase output currents (zero sequence current) must be the earth fault full compensation current, so the stabilized current of the three-phase current transformer should only flow between the three phases, i.e. the sum of the three-phase stabilized currents should be zero, and the DC-side stabilized current of each phase is
In the formula Iidc(i ═ a, B, C) is the regulated current for each phase itself generated in fig. 2.
The output current of the grounding bridge arm converter must always be kept as the grounding fault full compensation current, if the direct current side stabilized voltage current is superposed, the grounding fault current compensation is influenced, therefore, the output current can only stabilize the direct current side capacitor voltage by regulating and controlling the voltages at two ends of the output current, one end of the output current is directly grounded, the other end of the output current is connected to the common point of the three-phase converter, therefore, the voltage stabilization control of the direct current side of the grounding branch converter can only be realized by regulating the voltage at the common point, and the generation mode of the stabilized voltage is shown in fig. 2.
4. DC side voltage stabilization control
According to kirchhoff's law, substituting the parameters and voltage into the ground
If the current injected by the converter in the formula (10) is three-phase parameter unbalance current I to the groundZ＝I0bd＝EA·YA+EB·YB+EC·YCThe zero sequence voltage of the system is suppressed to zero; and if the zero sequence voltage of the control system is zero, the current injected by the converter is the three-phase earth parameter unbalanced current. Therefore, the three-phase unbalance current to ground parameters can be calculated by means of zero-sequence voltage measurement of the control system and current injection of the converter. The control strategy of the multifunctional converter is shown in fig. 2.
In order to make the technical solution of the present invention better understood by those skilled in the art, the present invention is further described below with reference to a simulation example.
And (4) building a power distribution network simulation model containing 6 feeders by using PSCAD software. The distribution line adopts a Bergeron model. For the distribution network shown in fig. 1, a phase a ground fault is set, and the asymmetry degree of the system to the ground parameters is 2.8%. And respectively putting a grounding bridge arm and a three-phase bridge arm of the multifunctional converter at 0.24s and 0.3s to compensate the reactive power and the asymmetric current, setting a grounding fault with a transition resistance of 10 omega at a bus at 0.4s, outputting a grounding fault compensation current at 0.5s, controlling the multifunctional converter to output a comprehensive compensation current for asymmetric current compensation, reactive compensation, grounding fault suppression and direct-current side capacitance voltage stabilization according to a split-phase control strategy, wherein the given compensation capacity of the reactive compensation is 1.0Mvar, and the compensation effect is shown in figure 3.
As can be seen from fig. 3, the multifunctional converter can simultaneously perform reactive compensation, asymmetric current compensation and ground fault suppression, and can ensure the dc-side capacitor voltage of the converter to be stable.
The invention provides a multifunctional compensation method for an asymmetric power distribution network, which is characterized in that a four-bridge-arm cascade H-bridge converter is taken as a multifunctional converter, three-phase bridge arms are in star connection and used for reactive power compensation, a grounding bridge arm formed by a single-phase cascade H-bridge converter is additionally arranged between a star connection point and the ground, a circulation loop is provided for single-phase grounding fault current, and the grounding fault current compensation is realized. The invention enables a set of converters to have the functions of single-phase earth fault suppression, asymmetric current compensation and reactive compensation at the same time, improves the utilization rate of equipment and enhances the economy of the equipment. The invention provides a three-phase converter ground fault compensation current calculation method and a converter direct-current side capacitor voltage stabilization current interphase control method which are adaptive to a multifunctional converter, the converter direct-current side capacitor voltage stabilization current is more uniformly distributed to each phase, the voltage stabilization current is ensured to only flow between phases without passing through a ground circuit, and effective cooperation of fault suppression and direct-current side capacitor voltage stable control is realized. The direct current side of the converter does not need to be additionally provided with an independent power supply, so that elements are saved, the equipment cost is reduced, and conditions are provided for popularization and application of the multifunctional converter.
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.
Claims (9)
1. A multifunctional compensation method for an asymmetric power distribution network is characterized in that a four-bridge-arm cascaded H-bridge converter without an independent direct current source is used as a multifunctional converter, and control strategies of the multifunctional converter are controlled in sequence.
2. The method as claimed in claim 1, wherein the multifunctional converter comprises a three-phase bridge arm using a three-phase H-bridge converter, the three-phase bridge arm is star-connected, and a grounding bridge arm using a single-phase H-bridge converter is additionally arranged between the star-connected point and the ground.
3. The multifunctional compensation method for the asymmetric power distribution network according to claim 2, wherein the three-phase H-bridge converter comprises a three-phase cascaded H-bridge and a connecting inductor, and the three-phase cascaded H-bridge comprises a two-level three-phase half-bridge, a three-level three-phase half-bridge, a multi-level three-phase half-bridge or a three-phase cascaded H-bridge; the single-phase H-bridge converter comprises a single-phase H-bridge and a connecting inductor, wherein the single-phase H-bridge comprises a two-level single-phase half bridge, a three-level single-phase half bridge, a multi-level single-phase half bridge or a single-phase cascading H-bridge; and the DC sides of the three-phase H-bridge converter and the single-phase H-bridge converter are not provided with independent DC sources.
4. The multifunctional compensation method for the asymmetric power distribution network according to claim 1, wherein the reactive compensation current target value calculation method comprises: according to the instantaneous power theory, a given reactive power target value is converted and calculated into a q-axis target current value through abc-dq conversion, a d-axis target current value is set to be zero, and then the target current values of the d axis and the q axis are inversely converted into a reference target value calculated by three-phase reactive compensation current through dq-abc.
5. The multifunctional compensation method for the asymmetric power distribution network according to claim 1, wherein the three-phase ground-to-ground parameter asymmetric compensation current calculation method comprises the following steps: and controlling the zero sequence voltage of the system to be zero, measuring the output current of the grounding bridge arm of the multifunctional converter at the moment, and taking the output current as a reference target value for calculating the asymmetric current.
6. The multifunctional compensation method for the asymmetric power distribution network according to claim 1, wherein the calculation method for the ground fault compensation current of the three-phase bridge arm converter comprises the following steps: the sum of the earth fault compensation currents of the three-phase bridge arm is always the earth fault full compensation current, namely the product of a negative value of a fault phase power supply voltage and a system ground admittance, the fault phase compensation current is the product of the negative value of the fault phase power supply voltage and a local ground admittance and a number 2, and the non-fault phase compensation current is the product of the local phase power supply voltage and the local ground admittance.
7. The multifunctional compensation method for the asymmetric power distribution network according to claim 1, wherein the interphase control method for the direct-current side capacitor regulated current of the three-phase bridge arm converter comprises the following steps: the stabilized current on the direct current side of the three-phase bridge arm converter only circulates at the interphase and does not pass through the ground branch, namely the sum of the three-phase stabilized current is always kept zero; and the total regulated current of each phase is obtained by the difference value of one half of the regulated current of the phase and the regulated currents of other two phases.
8. The multifunctional compensation method for the asymmetric power distribution network according to claim 1, wherein the calculation method for the ground fault compensation current of the grounding bridge arm converter comprises the following steps: the ground fault compensation current of the grounding bridge arm is the ground fault full compensation current, namely the product of the negative value of the fault phase power supply voltage and the system admittance to the ground.
9. The multifunctional compensation method for the asymmetric power distribution network according to claim 1, wherein the calculation method for the direct-current side capacitor regulated voltage of the ground bridge arm converter comprises the following steps: the output current of the grounding bridge arm is ensured to be the full compensation current of the grounding fault all the time, and the direct current side voltage stabilization of the grounding bridge arm converter adopts a mode of regulating and controlling the common point voltage of the three-phase bridge arm.
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| CN116191386A (en) * | 2023-03-14 | 2023-05-30 | 北京索英电气技术股份有限公司 | Flexible arc extinction device for faults |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116191386A (en) * | 2023-03-14 | 2023-05-30 | 北京索英电气技术股份有限公司 | Flexible arc extinction device for faults |
| CN116191386B (en) * | 2023-03-14 | 2023-11-14 | 北京索英电气技术股份有限公司 | Flexible arc extinction device for faults |
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