CN111371092B - Automatic control method, device, equipment and storage medium for self-healing of power distribution network - Google Patents

Automatic control method, device, equipment and storage medium for self-healing of power distribution network Download PDF

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CN111371092B
CN111371092B CN202010282775.8A CN202010282775A CN111371092B CN 111371092 B CN111371092 B CN 111371092B CN 202010282775 A CN202010282775 A CN 202010282775A CN 111371092 B CN111371092 B CN 111371092B
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converter
fault point
distribution network
fault
current
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CN111371092A (en
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赵瑞锋
李波
卢建刚
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Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd
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Electric Power Dispatch Control Center of Guangdong Power Grid Co Ltd
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    • 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
    • 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
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/14—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by switching loads on to, or off from, network, e.g. progressively balanced loading
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y02B70/3225—Demand response systems, e.g. load shedding, peak shaving
    • 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
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems
    • Y04S20/222—Demand response systems, e.g. load shedding, peak shaving

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  • Power Engineering (AREA)
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Abstract

The application discloses a method, a device, equipment and a storage medium for automatically controlling self-healing of a power distribution network, wherein the method comprises the following steps: s1, when the power distribution network is in fault, judging whether a fault area in the power distribution network is in an active state, if so, executing the step S2 to the step S3, and if not, executing the step S4 to the step S5; s2, positioning the fault area to determine a fault point, and outputting a negative sequence current signal to the fault point through a first current converter connected to the fault point; s3, after the outgoing line breaker of the line where the fault point is located is disconnected, adjusting the first current converter to work in a passive constant voltage and constant frequency state, disconnecting the load switches on two sides of the fault point, and closing the outgoing line breaker; s4, positioning the fault area to determine a fault point, and controlling a first current converter connected to the fault point to work in a normal current limiting state; and S5, adjusting the first converter to the over-current limiting state for a preset time, and disconnecting the load switches on two sides of the fault point.

Description

Automatic control method, device, equipment and storage medium for self-healing of power distribution network
Technical Field
The application relates to the technical field of power distribution networks, in particular to an automatic control method, device, equipment and storage medium for self-healing of a power distribution network.
Background
The power distribution network fault self-healing means that after a fault occurs in a power distribution network, the topological structure of the power distribution network is changed by adjusting the positions of a section switch and a contact switch, and a non-fault power failure area is quickly self-healed. The core of the self-healing of the power distribution network is high-quality uninterrupted power supply, and meanwhile, when the power grid fails, the power failure range and the power failure time can be reduced to the maximum extent. However, in the existing power system, attention is not paid to the development of the power distribution network, output funds are not enough, and the self-healing level of the existing power distribution network needs to be further developed and optimized.
After the power distribution network is connected with power electronic equipment such as a direct-current power distribution network, load transfer and power quality optimization can be effectively achieved. However, in the present phase, because the automation level of the power distribution network is still low and related equipment facilities are still lagged behind, how to effectively match the current converter with the traditional switch of the power distribution network to realize reliable power supply and effective self-healing of the power distribution network to the greatest extent is a problem to be paid much attention.
Therefore, it is an urgent technical problem to be solved by those skilled in the art to provide an automatic control method for self-healing of a power distribution network.
Disclosure of Invention
The application provides an automatic control method, device, equipment and storage medium for self-healing of a power distribution network, which can combine a converter and a traditional switch in the power distribution network to realize rapid power supply and effective self-healing of the power distribution network.
In view of this, the first aspect of the present application provides an automatic control method for self-healing of a power distribution network, including:
s1, when the power distribution network is in fault, judging whether a fault area in the power distribution network is in an active state, if so, executing the step S2 to the step S3, and if not, executing the step S4 to the step S5;
s2, positioning the fault area to determine a fault point, and outputting a negative sequence current signal to the fault point through a first converter connected to the fault point;
s3, after the outgoing line breaker of the line where the fault point is located is disconnected, the first current converter is adjusted to work in a passive constant voltage and constant frequency state, load switches on two sides of the fault point are disconnected, and the outgoing line breaker is closed;
s4, positioning the fault region to determine a fault point, and controlling a first converter connected to the fault point to work in a normal current limiting state, wherein in the normal current limiting state, the output current of the first converter meets a preset constraint condition;
and S5, adjusting the first converter to an over-current limiting state preset time length, and disconnecting the load switches on two sides of the fault point.
Optionally, step S2 specifically includes:
s21, positioning the fault area to determine a fault point, and acquiring the working state of the first current converter connected to the fault point;
s22, when the first converter is in a constant power control state, controlling the first converter to input a negative sequence current signal to the fault point;
and S23, when the first converter is in a constant direct current voltage control state, controlling the first converter to output the negative sequence current signal, and controlling a second converter to output a direct current voltage slope control signal, wherein the second converter is other converters in the power distribution network except the first converter.
Optionally, the dc voltage slope control signal is:
ΔP＝k(Udr-Udm)；
wherein, Delta P is the active power increment of the DC voltage slope control signal, UdrIs a DC voltage command value, UdmFor dc voltage measurements, k is the slope.
Optionally, step S3 is followed by:
and according to a preset priority sequence, adjusting the second converter with the highest priority to work in the direct-current voltage control state, and controlling other second converters to stop outputting direct-current voltage slope control signals.
Optionally, after the load switches on both sides of the fault point are opened, before the outlet circuit breaker is closed, the method further includes:
and when the maximum output power of the first converter is judged to be smaller than the total load of the passive network, the loads with preset number are cut out in a reverse order according to the importance degree sequence of the loads in the power distribution network.
Optionally, the preset constraint condition is:
Figure BDA0002447345720000031
wherein, Um、ImFor the effective values of the AC voltage and AC current, S, of the distribution networkmaxMaximum allowable output capacity for inverter, IarmFor bridge arm current, ImaxThe maximum value that allows bridge arm current to flow.
Optionally, step S5 is followed by:
and controlling the first converter to work to a constant voltage and constant frequency state.
The second aspect of the application provides an automatic control device of distribution network self-healing, include:
the system comprises a judging unit, a first adjusting unit and a second adjusting unit, wherein the judging unit is used for judging whether a fault area in the power distribution network is in an active state or not when the power distribution network has a fault, if so, the first controlling unit and the first adjusting unit are triggered, and if not, the second controlling unit and the second adjusting unit are triggered;
the first control unit is used for positioning the fault area to determine a fault point and outputting a negative sequence current signal to the fault point through a first converter connected to the fault point;
the first adjusting unit is used for adjusting the first converter to work in a passive constant voltage and constant frequency state after an outgoing line breaker of a line where the fault point is located is disconnected, disconnecting load switches on two sides of the fault point and closing the outgoing line breaker;
the second control unit is used for positioning the fault region to determine a fault point and controlling a first converter connected to the fault point to work in a normal current limiting state, wherein in the normal current limiting state, the output current of the first converter meets a preset constraint condition;
and the second adjusting unit is used for adjusting the first converter to an over-current-limiting state preset time length and disconnecting the load switches on two sides of the fault point.
The third aspect of the application provides an automatic control device for self-healing of a power distribution network, which comprises a processor and a memory;
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the automatic control method for self-healing of the power distribution network according to the instructions in the program code.
A fourth aspect of the present application provides a storage medium, where the storage medium is used to store program codes, and the program codes are used to execute the automatic control method for self-healing of the power distribution network according to the first aspect.
According to the technical scheme, the embodiment of the application has the following advantages:
the application provides an automatic control method for self-healing of a power distribution network, which comprises the following steps: s1, when the power distribution network is in fault, judging whether a fault area in the power distribution network is in an active state, if so, executing the step S2 to the step S3, and if not, executing the step S4 to the step S5; s2, positioning the fault area to determine a fault point, and outputting a negative sequence current signal to the fault point through a first current converter connected to the fault point; s3, after the outgoing line breaker of the line where the fault point is located is disconnected, adjusting the first current converter to work in a passive constant voltage and constant frequency state, disconnecting the load switches on two sides of the fault point, and closing the outgoing line breaker; s4, positioning the fault area to determine a fault point, and controlling a first current converter connected to the fault point to work in a normal current limiting state, wherein in the normal current limiting state, the output current of the first current converter meets a preset constraint condition; and S5, adjusting the first converter to the over-current limiting state for a preset time, and disconnecting the load switches on two sides of the fault point. According to the control method for the self-healing of the power distribution network, on the basis of the switching of the existing power distribution network, the control modes of the current converter in different stages are switched and matched during fault processing of the power distribution network, continuous power supply of loads can be achieved to the maximum extent, and rapid power supply and effective self-healing of the power distribution network are achieved to a large extent.
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Fig. 1 is a schematic flowchart of a first embodiment of an automatic control method for self-healing of a power distribution network according to an embodiment of the present application;
fig. 2 is a schematic flowchart of a self-healing automatic control method for a power distribution network according to a second embodiment of the present disclosure;
fig. 3 is a schematic diagram of a power distribution network structure of an application example in the embodiment of the present application;
fig. 4 is a schematic flow chart of self-healing control corresponding to fig. 3;
FIG. 5 is a schematic diagram of the flow of fault current during a fault in an active distribution network;
FIG. 6 is a schematic diagram of the flow of fault current during a fault in a passive distribution network;
FIG. 7 is a schematic diagram of an overcurrent inverse time limit curve for a power electronic device;
fig. 8 is a schematic structural diagram of an automatic control device for self-healing of a power distribution network in an embodiment of the present application.
Detailed Description
The embodiment of the application provides an automatic control method, device, equipment and storage medium for self-healing of a power distribution network, and a converter and a traditional switch in the power distribution network can be combined to realize rapid power supply and effective self-healing of the power distribution network.
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, a schematic flow chart of a first embodiment of an automatic control method for self-healing of a power distribution network in an embodiment of the present application includes:
step 101, when the power distribution network is in fault, judging whether a fault area in the power distribution network is in an active state, if so, executing step 102 to step 103, and if not, executing step 104 to step 105.
When the power distribution network has a fault, when the converter and a conventional switch in the existing power distribution network are combined, whether a fault area in the power distribution network is in an active state needs to be judged, and measures taken in the active state and the passive state are different, which is specifically referred to the following description and is not repeated herein.
And 102, positioning the fault area to determine a fault point, and outputting a negative sequence current signal to the fault point through a first converter connected to the fault point.
When the fault area is in an active state, the fault area is located to determine a fault point, and a negative sequence current signal is output to the fault point through a first converter connected to the fault point.
And 103, after the outgoing line breaker of the line where the fault point is located is disconnected, adjusting the first current converter to work in a passive constant voltage and constant frequency state, disconnecting load switches on two sides of the fault point, and closing the outgoing line breaker.
After the first current converter is controlled to output a negative sequence current signal to a fault point, the outgoing line breaker of the fault point is disconnected, the first current converter is adjusted to work in a passive constant voltage and constant frequency state, load switches on two sides of the fault point are disconnected, and the outgoing line breaker is closed, so that power supply recovery of the power distribution network in an active state is achieved.
The load switches on two sides of a fault point are disconnected, namely, fault isolation is realized, and the outgoing line breaker is closed to realize power supply recovery of the power distribution network.
And 104, positioning the fault region to determine a fault point, and controlling a first current converter connected to the fault point to work in a normal current limiting state, wherein the output current of the first current converter in the normal current limiting state meets a preset constraint condition.
When the fault area is in a passive state, firstly, the fault area is positioned to determine a fault point, and a first current converter connected to the fault point is controlled to work in a normal current limiting state, wherein the output current of the first current converter in the normal current limiting state meets a preset constraint condition.
And 105, adjusting the first current converter to an over-current limiting state preset time length, and disconnecting load switches on two sides of a fault point.
In the process of controlling the first converter to work in a normal current limiting state, the first converter is adjusted to be in an over current limiting state for preset time, load switches on two sides of a fault point are disconnected, fault isolation is achieved, and then power can be supplied.
According to the automatic control method for the self-healing of the power distribution network in the embodiment, on the basis of the switching of the existing power distribution network, the continuous power supply of the load can be realized to the greatest extent by switching and matching the control modes of the current converter in different stages during the fault processing of the power distribution network, and the rapid power supply and the effective self-healing of the power distribution network can be realized to a large extent.
The above is a first embodiment of an automatic control method for self-healing of a power distribution network provided by the embodiment of the present application, and the following is a second embodiment of the automatic control method for self-healing of a power distribution network provided by the embodiment of the present application.
Referring to fig. 2, a schematic flow chart of a second embodiment of an automatic control method for self-healing of a power distribution network in the embodiment of the present application includes:
step 201, when the power distribution network is in fault, judging whether a fault area in the power distribution network is in an active state, if so, executing step 202 to step 206, and if not, executing step 207 to step 209.
It should be noted that step 201 is the same as the description of step 101 in the first embodiment, and reference may be specifically made to the description of step 101, which is not described herein again.
Step 202, positioning the fault area to determine a fault point, and acquiring the working state of the first converter connected to the fault point.
After the fault area is located and the fault point is determined, the subsequent steps are performed according to the working state of the first converter, so that the working state of the first converter connected to the fault point is firstly obtained.
And 203, when the first converter is in a constant power control state, controlling the first converter to input a negative sequence current signal to a fault point.
And step 204, when the first converter is in a constant direct current voltage control state, controlling the first converter to output a negative sequence current signal, and the second converter to output a direct current voltage slope control signal.
It should be noted that the second converter in step 204 is another converter in the power distribution network except the first converter.
The direct current voltage slope control signal is:
ΔP＝k(Udr-Udm)；
wherein, Delta P is the active power increment of the DC voltage slope control signal, UdrIs a DC voltage command value, UdmFor dc voltage measurements, k is the slope.
And step 205, after the outgoing line breaker of the line where the fault point is located is disconnected, adjusting the first converter to work in a passive constant voltage and constant frequency state, disconnecting the load switches on two sides of the fault point, and closing the outgoing line breaker.
It should be noted that, after the load switches on both sides of the fault point are opened, before the outgoing line breaker is closed, the method further includes:
and when the maximum output power of the first converter is judged to be smaller than the total load of the passive network, the loads with the preset number are cut off in a reverse order according to the importance degree sequence of the loads in the power distribution network. And the load is cut off from the least important load so as to ensure the stability of the system voltage and frequency in the power distribution network under the passive condition.
And step 206, according to the preset priority sequence, adjusting the second converter with the highest priority to work in a direct-current voltage control state, and controlling other second converters to stop outputting direct-current voltage slope control signals.
For the converter which is put into the direct-current voltage slope control state, the second converter with the highest priority is switched into the fixed direct-current voltage control state according to the priority order which is agreed in advance, and meanwhile, other second converters quit the direct-current voltage slope control state, so that the effective regulation of the system power flow is ensured, the direct-current voltage control in the power distribution network is ensured to be more stable, and the power flow control is more accurate.
And step 207, positioning the fault area to determine a fault point, and controlling the first converter connected to the fault point to work in a normal current limiting state.
When in a normal current limiting state, the output current of the first current converter meets preset constraint conditions, wherein the preset constraint conditions are as follows:
Figure BDA0002447345720000071
wherein, Um、ImFor the effective values of the AC voltage and AC current, S, of the distribution networkmaxMaximum allowable output capacity for inverter, IarmFor bridge arm current, ImaxThe maximum value that allows bridge arm current to flow.
And step 208, adjusting the first converter to the over-current limiting state for preset time, and disconnecting the load switches on two sides of the fault point.
The over-current limiting state is that the short-time overcurrent capacity of power electronic devices in the converter is utilized, the output current of the converter is rapidly increased to a level higher than the normal allowable overcurrent level within hundred milliseconds, and effective starting and judging signals are provided for protection judgment such as fault positioning and the like by utilizing short-time large-amplitude overcurrent, so that effective positioning and protection of faults under the passive power distribution network are promoted, and therefore, the preset time is short in the embodiment.
And step 209, controlling the first converter to work to a constant voltage and constant frequency state.
According to the automatic control method for the self-healing of the power distribution network in the embodiment, on the basis of the switching of the existing power distribution network, the continuous power supply of the load can be realized to the greatest extent by switching and matching the control modes of the current converter in different stages during the fault processing of the power distribution network, and the rapid power supply and the effective self-healing of the power distribution network can be realized to a large extent.
The above is a second embodiment of the automatic control method for self-healing of the power distribution network according to the embodiment of the present application, and the following is an application example of the automatic control method for self-healing of the power distribution network according to the embodiment of the present application, please refer to fig. 3 to fig. 7.
In the configuration of the distribution network shown in fig. 3, BK1 and BK2 are outgoing line breakers, Q11 to Q34 are Load switches, Load1 to Load9 are loads, C1, C2 and C3 are inverters, S1, S2 and S3 represent three supply areas, the supply area S3 is in a passive state, and S1 and S2 are in an active state. The power distribution network fault self-healing control method is related to power distribution network active and passive, and the whole self-healing control logic is shown in fig. 4.
If the distribution network supply area is in an active state, such as S1 and S2, when a fault occurs at F1, the self-healing control steps are as follows:
1) the distribution network carries out fault location according to the existing protection logic, the fault point is determined to be S1, the flowing direction of the fault current in S1 is shown in figure 5 at the position of an alternating current feeder F1, and the fault current is fed into the fault point by the distribution network and an inverter C1 at the same time.
If the converter C1 connected with the fault point is in a constant power control state, the converter C1 outputs a negative sequence current signal; if the converter C1 connected to the fault point is in the constant DC voltage control state, the converter C1 outputs a negative sequence current signal, and simultaneously, the converter C2 in the constant power control in the DC system outputs a DC voltage slope control signal.
The direct current voltage slope control refers to an active power command value P in an active power control looprAnd increasing the increment value delta P of the active power to achieve the effect of controlling the active-voltage slope.
ΔP＝k(Udr-Udm)；
Wherein, Delta P is the active power increment of the DC voltage slope control signal, UdrIs a DC voltage command value, UdmFor dc voltage measurements, k is the slope.
2) After the fault location is completed, the outgoing line breaker BK1 of the line where the fault point is located is opened. After the circuit breaker BK1 is opened, the inverter C1 is switched to a passive constant-voltage constant-frequency state from a current control state; meanwhile, load switches Q12 and Q13 on two sides of the line section where the fault point is located are disconnected, and fault isolation is achieved.
In the process, after the load switches Q12 and Q13 are disconnected, if the maximum power Pcmax which can be output by the converter C1 is larger than the total load of the passive network, the load shedding of the power distribution network is not needed; if Pcmax is less than the total load of the passive network, the load is cut off from the least important load according to the load importance degree agreed in advance, so as to ensure the stability of the system voltage and frequency under the passive condition.
3) After the load switch is opened, the outlet line breaker BK1 is closed again to supply power again to the load upstream of the fault point. Thus, the loads at the upstream of the fault point in the S1 area are supplied by an alternating current system, and the loads at the downstream of the fault point are supplied by an inverter C1, namely the loads Load1 and Load2 at the upstream of the fault point are supplied by a power distribution network; the Load3 downstream of the fault point is powered by inverter C1.
4) For the current converter outputting the direct current voltage slope control state, the current converter with the highest priority is switched to be controlled by the fixed direct current voltage according to the priority order agreed in advance, and meanwhile, other current converters exit from the direct current voltage slope control state to ensure the effective regulation of the system power flow.
If the distribution network supply area is in a passive state, as in S3, when a fault occurs at F2, the self-healing control steps are as follows:
1) fig. 6 shows the current flow direction of the fault current after the fault occurs at the ac feeder F2 of S3. And the converter C3 connected with the fault point enters a normal current limiting state from a passive constant-voltage constant-frequency control state so as to ensure that the fault current is not too large to cause overcurrent damage of the converter C3.
Under the normal current limiting state, the alternating current output by the current converter is limited by the output power and the bridge arm current shown by the following formula:
Figure BDA0002447345720000091
wherein, Um、ImFor the effective values of the AC voltage and AC current, S, of the distribution networkmaxMaximum allowable output capacity for inverter, IarmFor bridge arm current, ImaxThe maximum value that allows bridge arm current to flow.
2) And switching the current converter C3 from the normal current limiting state to the over current limiting state for a short time, and completing fault positioning by matching with a fault positioning device.
The power electronic device has the over-current operation capability for a certain time. The current in the normal current limiting state is the maximum current that the power electronics device allows to flow for a long time. However, the maximum current in the current limiting state is still much smaller than the original fault current of the distribution network. This may result in the ac fault protection not being able to start properly. Therefore, it is necessary to increase the current value to ensure the proper operation of the ac protection and to realize functions such as fault location.
FIG. 7 shows the inverse time-limited overcurrent curve for a power electronic device, where ImaxIn accordance with the above formula, I is the maximum value that allows the bridge arm current to flowmaxsThe us stage allows the maximum value of the overcurrent. In the actual use process, the corresponding current I can be selected according to the setting parameters and the setting time requirements of the protection action of the power distribution networkopAnd time topTo meet the practical requirements.
3) And after the fault location is completed, disconnecting the load switches Q32 and Q33 on two sides of the line section where the fault point is located, and realizing fault isolation.
4) After fault isolation, if the converter C3 is still in the normal current limiting state, the converter C3 is switched back to the constant voltage and constant frequency control state from the normal current limiting state by cutting off part of the load, and short-time overload operation is allowed.
The above is an application example of the automatic control method for self-healing of the power distribution network according to the embodiment of the present application, and the following is an embodiment of an automatic control device for self-healing of the power distribution network according to the embodiment of the present application, please refer to fig. 8.
The automatic control device of distribution network self-healing that provides in the embodiment of this application includes:
a determining unit 801, configured to determine, when a power distribution network fails, whether a failure area in the power distribution network is in an active state, if so, trigger a first control unit 802 and a first adjusting unit 803, and if not, trigger a second control unit 804 and a second adjusting unit 805;
the first control unit 802 is configured to locate a fault area to determine a fault point, and output a negative sequence current signal to the fault point through a first converter connected to the fault point;
the first adjusting unit 803 is configured to adjust the first converter to operate in a passive constant-voltage constant-frequency state after the outgoing line breaker of the line where the fault point is located is disconnected, disconnect load switches on two sides of the fault point, and close the outgoing line breaker;
the second control unit 804 is configured to locate a fault region to determine a fault point, and control the first converter connected to the fault point to operate in a normal current limiting state, where in the normal current limiting state, an output current of the first converter meets a preset constraint condition;
and a second adjusting unit 805, configured to adjust the first converter to an over-current-limiting state for a preset time period, and disconnect the load switches on two sides of the fault point.
The automatic control device of distribution network self-healing in this embodiment, on the basis of the switch of current distribution network, utilize the control mode switching and the cooperation of transverter different stages when the distribution network fault handling, can realize the continuous power supply of load by the at utmost, the quick power supply and the effective self-healing of distribution network are realized to a large extent.
The embodiment of the application also provides an embodiment of automatic control equipment for self-healing of the power distribution network, and the embodiment comprises a processor and a memory; the memory is used for storing the program codes and transmitting the program codes to the processor; the processor is configured to execute the automatic control method for self-healing of the power distribution network according to the first embodiment or the second embodiment according to instructions in the program code.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
An embodiment of the present application further provides a storage medium, where the storage medium is configured to store a program code, and the program code is configured to execute the automatic control method for self-healing of the power distribution network according to the first embodiment or the second embodiment.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims (5)

1. An automatic control method for self-healing of a power distribution network is characterized by comprising the following steps:
s1, when the power distribution network is in fault, judging whether a fault area in the power distribution network is in an active state, if so, executing the step S2 to the step S3, and if not, executing the step S4 to the step S5;
s2, positioning the fault area to determine a fault point, and outputting a negative sequence current signal to the fault point through a first converter connected to the fault point;
s3, after the outgoing line breaker of the line where the fault point is located is disconnected, the first current converter is adjusted to work in a passive constant voltage and constant frequency state, load switches on two sides of the fault point are disconnected, and the outgoing line breaker is closed;
s4, positioning the fault region to determine a fault point, and controlling a first converter connected to the fault point to work in a normal current limiting state, wherein the output current of the first converter meets a preset constraint condition in the normal current limiting state;
s5, switching the first converter to an over-current-limiting state for a preset time length in a short time, and disconnecting the load switches on two sides of the fault point after positioning is completed;
step S2 specifically includes:
s21, positioning the fault area to determine a fault point, and acquiring the working state of the first current converter connected to the fault point;
s22, when the first converter is in a constant power control state, controlling the first converter to input a negative sequence current signal to the fault point;
s23, when the first converter is in a constant direct current voltage control state, controlling the first converter to output the negative sequence current signal, and controlling a second converter to output a direct current voltage slope control signal, wherein the second converter is another converter in the power distribution network except the first converter;
step S3 is followed by:
according to a preset priority sequence, adjusting the second converter with the highest priority to work in the constant direct-current voltage control state, and controlling other second converters to stop outputting direct-current voltage slope control signals;
after the load switches on two sides of the fault point are opened, the method also comprises the following steps before the outgoing line breaker is closed:
when the maximum output power of the first converter is judged to be smaller than the total load of the passive network, the loads with preset number are cut out in a reverse order according to the importance degree sequence of the loads in the power distribution network;
step S5 is followed by:
controlling the first converter to work to a constant voltage and constant frequency state;
the preset constraint conditions are as follows:
Figure FDA0003436712610000021
wherein, Um、ImFor the effective values of the AC voltage and AC current, S, of the distribution networkmaxMaximum allowable output capacity for inverter, IarmFor bridge arm current, ImaxThe maximum value that allows bridge arm current to flow.
2. The automatic control method for self-healing of the power distribution network according to claim 1, wherein the dc voltage slope control signal is:
ΔP＝k(Udr-Udm)；
wherein, Delta P is the active power increment of the DC voltage slope control signal, UdrIs a DC voltage command value, UdmFor dc voltage measurements, k is the slope.
3. The utility model provides an automatic control device of distribution network self-healing which characterized in that includes:
the system comprises a judging unit, a first adjusting unit and a second adjusting unit, wherein the judging unit is used for judging whether a fault area in the power distribution network is in an active state or not when the power distribution network has a fault, if so, the first controlling unit and the first adjusting unit are triggered, and if not, the second controlling unit and the second adjusting unit are triggered;
the first control unit is used for positioning the fault area to determine a fault point and outputting a negative sequence current signal to the fault point through a first converter connected to the fault point;
the first adjusting unit is used for adjusting the first converter to work in a passive constant voltage and constant frequency state after an outgoing line breaker of a line where the fault point is located is disconnected, disconnecting load switches on two sides of the fault point and closing the outgoing line breaker;
the second control unit is used for positioning the fault region to determine a fault point and controlling a first converter connected to the fault point to work in a normal current limiting state, wherein in the normal current limiting state, the output current of the first converter meets a preset constraint condition;
the second adjusting unit is used for switching the first converter to an over-current limiting state for a preset time length in a short time and disconnecting the load switches on two sides of the fault point after positioning is completed;
locating the fault area to determine a fault point, and outputting a negative-sequence current signal to the fault point through a first converter connected to the fault point specifically includes:
s21, positioning the fault area to determine a fault point, and acquiring the working state of the first current converter connected to the fault point;
s22, when the first converter is in a constant power control state, controlling the first converter to input a negative sequence current signal to the fault point;
s23, when the first converter is in a constant direct current voltage control state, controlling the first converter to output the negative sequence current signal, and controlling a second converter to output a direct current voltage slope control signal, wherein the second converter is another converter in the power distribution network except the first converter;
the automatic control device further includes:
the third adjusting unit is used for adjusting the second converter with the highest priority to work in the constant direct-current voltage control state according to a preset priority sequence and controlling other second converters to stop outputting direct-current voltage slope control signals;
the cutting unit is used for cutting off the loads in a preset number in a reverse order according to the importance degree sequence of the loads in the power distribution network when the maximum output power of the first converter is judged to be smaller than the total load of the passive network;
the third control unit is used for controlling the first converter to work to a constant voltage and constant frequency state;
the preset constraint conditions are as follows:
Figure FDA0003436712610000031
wherein, Um、ImFor the effective values of the AC voltage and AC current, S, of the distribution networkmaxMaximum allowable output capacity for inverter, IarmFor bridge arm current, ImaxThe maximum value that allows bridge arm current to flow.
4. The automatic control equipment for self-healing of the power distribution network is characterized by comprising a processor and a memory;
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is configured to execute the automatic control method for self-healing of the power distribution network according to any one of claims 1 to 2 according to instructions in the program code.
5. A storage medium for storing program code for executing the automatic control method for self-healing of the power distribution network according to any one of claims 1 to 2.
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