CN115189389A - Commutation fault suppression method, system, device and storage medium for weak receiving end HVDC system - Google Patents

Commutation fault suppression method, system, device and storage medium for weak receiving end HVDC system Download PDF

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CN115189389A
CN115189389A CN202210832181.9A CN202210832181A CN115189389A CN 115189389 A CN115189389 A CN 115189389A CN 202210832181 A CN202210832181 A CN 202210832181A CN 115189389 A CN115189389 A CN 115189389A
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parameter
voltage
reactive power
grid
reactive
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邢超
陈俊皓
奚鑫泽
李胜男
陈仕龙
刘明群
徐志
李俊鹏
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Electric Power Research Institute of Yunnan Power Grid Co Ltd
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Electric Power Research Institute of Yunnan Power Grid Co Ltd
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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
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • 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
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • 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
    • 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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • 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
    • Y02E40/10—Flexible AC transmission systems [FACTS]

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  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

The embodiment of the invention discloses a method, a system, a device and a storage medium for suppressing a commutation fault of a weak receiving-end HVDC system, belonging to the field of a DC power transmission system, wherein the method comprises the steps of acquiring reactive compensation parameters and electric signal parameters of a grid-connected point when an AC fault occurs on an inversion side, and acquiring target voltage parameters of an energy storage type static synchronous compensator corresponding to a DC side; calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters; and driving the energy storage type static synchronous compensator based on the reactive control parameter, and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault. When reactive compensation is carried out, the capacitor voltage parameter at the direct current side is stabilized, and the stability of the weak receiving end HVDC system is improved.

Description

Weak receiving end HVDC system commutation fault suppression method, system, device and storage medium
Technical Field
The invention relates to the technical field of direct current transmission systems, in particular to a method, a system, a device and a storage medium for suppressing a commutation fault of a weak receiving-end HVDC system.
Background
When the inversion side of the weak receiving end HVDC system has a fault, the voltage of the bus at the inversion side is easy to drop, and the phase change failure of the HVDC system is caused. In the prior art, a reactive compensation device is additionally arranged to maintain the voltage of a bus at the inverter side, so that the phase change fault is prevented. However, when the reactive compensation device performs reactive compensation, the control precision of the outer ring of the voltage on the direct current side is often affected, so that the voltage on the direct current side is greatly oscillated, and meanwhile, harmonic components exist in the output current, so that the operation stability of the weak receiving end HVDC system is affected.
Disclosure of Invention
In view of the above, the present invention provides a method, a system, a device and a storage medium for suppressing a commutation fault of a weak receiving-end HVDC system, which are used to solve the problem of the reduction of reactive compensation stability of the weak receiving-end HVDC system due to a reactive compensation device in the prior art. To achieve one of, a part of, or all of the above objects, or other objects, the present invention provides a method, a system, an apparatus, and a storage medium for suppressing commutation fault of a weak receiving-end HVDC system, where in a first aspect:
a weak receiving end HVDC system commutation fault suppression method comprises the following steps:
when an alternating current fault occurs on the inversion side, acquiring reactive compensation parameters, electric signal parameters of a grid connection point and target voltage parameters of the energy storage type static synchronous compensator corresponding to the direct current side;
calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters;
and driving the energy storage type static synchronous compensator based on the reactive control parameter, and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault.
Preferably, the target voltage parameter includes a capacitance real-time voltage parameter and a capacitance reference voltage parameter at the dc side;
the step of adjusting the capacitor voltage parameter on the dc side based on the target voltage parameter comprises:
obtaining a first voltage parameter by subtracting the capacitance reference voltage parameter from the capacitance real-time voltage parameter;
processing the first voltage parameter by using a proportional-integral model to obtain an active current parameter;
taking the active current parameter as the input current of a preset drive circuit to obtain the capacitor voltage parameter;
judging whether the difference value of the capacitor voltage parameter and the capacitor reference voltage parameter meets a preset threshold condition or not;
if not, taking the capacitor voltage parameter as the capacitor real-time voltage parameter, and executing the step to obtain a first voltage parameter after the difference is made between the capacitor reference voltage parameter and the capacitor real-time voltage parameter;
and if so, judging that the adjustment of the capacitor voltage parameter on the direct current side is finished.
Preferably, before the obtaining the first voltage parameter by subtracting the capacitance reference voltage parameter from the capacitance real-time voltage parameter, the method further includes:
judging whether the active power instruction parameter is zero or not;
and if not, setting the active power instruction parameter to zero.
Preferably, the electrical signal parameters include a grid-connected point voltage per unit parameter, a grid-connected point bus voltage upper limit parameter, and a grid-connected point bus voltage lower limit parameter;
the step of calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters comprises:
calculating by using a reactive power model to obtain a first reactive power compensation parameter according to the comparison result of the grid-connected point voltage per unit parameter, the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter; the reactive power model comprises the reactive compensation parameters;
and processing the first reactive power compensation parameter by using a proportional-integral model to obtain the reactive power control parameter.
Preferably, the reactive compensation parameters comprise a reactive proportionality coefficient and rated current parameters of the energy storage type static synchronous compensator;
the step of obtaining a first reactive power compensation parameter by utilizing reactive power model calculation according to the comparison result of the grid-connected point voltage per unit parameter, the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter comprises the following steps:
when the grid-connected point voltage per unit parameter is located between the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter, calculating by using the reactive scaling factor, the grid-connected point bus voltage upper limit parameter, the grid-connected point voltage per unit parameter and the rated current parameter to obtain the first reactive power compensation parameter;
when the per-unit voltage parameter of the grid-connected point is smaller than the lower limit parameter of the bus voltage of the grid-connected point, calculating by using the rated current parameter and the per-unit voltage parameter of the grid-connected point to obtain a first reactive power compensation parameter;
and when the per-unit voltage parameter of the grid-connected point is greater than the upper limit voltage parameter of the grid-connected point bus, taking a preset fixed parameter as the first reactive power compensation parameter.
Preferably, before the processing the first reactive power compensation parameter by using a proportional-integral model, the method further includes:
judging whether the turn-off angle of the converter valve on the inversion side is reduced or not;
if so, acquiring a turn-off angle real-time parameter and a turn-off angle reference parameter of the turn-off angle of the converter valve;
obtaining a turn-off angle difference parameter by subtracting the turn-off angle real-time parameter from the turn-off angle reference parameter;
processing the turn-off angle difference parameter by using a proportional-integral model to obtain a second reactive power compensation parameter; the second reactive power compensation parameter is within the rated power range of the energy storage type static synchronous compensator;
and summing the first reactive power compensation parameter and the second reactive power compensation parameter to obtain a reactive power summation parameter, and processing the reactive power summation parameter by using the proportional-integral model to obtain the reactive power control parameter.
Preferably, when no ac fault occurs on the inverter side, a first active power current parameter is calculated based on the obtained active power instruction parameter, the inverter side bus voltage parameter and the current proportionality coefficient;
transforming the obtained three-phase voltage parameters through coordinates to obtain voltage amplitude phase parameters;
processing the voltage amplitude phase parameter by using a phase-locked loop circuit to obtain real-time frequency;
obtaining difference frequency after the real-time frequency is different from the obtained rated frequency;
processing the difference frequency by using a proportional-integral model to obtain a second active power current parameter;
summing the first active power current parameter and the second active power current parameter to obtain an active power summing parameter, and processing the active power summing parameter by using the proportional-integral model to obtain an active control parameter;
when a reactive power instruction parameter is received, calculating to obtain a reactive power current parameter based on the reactive power instruction parameter, the inversion side bus voltage parameter and the current proportion coefficient;
processing the reactive power current parameter by using the proportional-integral model to obtain a reactive driving parameter;
when an alternating-current voltage instruction is received, acquiring an alternating-current bus real-time voltage parameter and an alternating-current bus reference voltage parameter;
and subtracting the real-time voltage parameter of the alternating-current bus from the reference voltage parameter of the alternating-current bus to obtain a voltage difference value parameter of the alternating-current bus, and processing the voltage difference value parameter of the alternating-current bus by using the proportional-integral model to obtain the reactive power driving parameter.
In a second aspect:
a weak receiving end HVDC system commutation fault suppression system comprises an acquisition module, a phase-changing module and a phase-changing module, wherein the acquisition module is used for acquiring reactive compensation parameters and electric signal parameters of a grid-connected point and target voltage parameters of an energy storage type static synchronous compensator corresponding to a direct current side when an alternating current fault occurs on an inversion side;
the reactive power module is used for calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters;
and the adjusting module is used for driving the energy storage type static synchronous compensator based on the reactive control parameter and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault.
Preferably, the target voltage parameter includes a capacitance real-time voltage parameter and a capacitance reference voltage parameter at the dc side;
the adjusting module comprises a first voltage unit, and is used for obtaining a first voltage parameter after the difference is made between the capacitance reference voltage parameter and the capacitance real-time voltage parameter;
the active current unit is used for processing the first voltage parameter by using a proportional-integral model to obtain an active current parameter;
the capacitor voltage unit is used for taking the active current parameter as the input current of a preset driving circuit to obtain the capacitor voltage parameter;
the threshold condition unit is used for judging whether the difference value of the capacitor voltage parameter and the capacitor reference voltage parameter meets a preset threshold condition or not;
if not, taking the capacitor voltage parameter as the capacitor real-time voltage parameter, and executing the step to make a difference between the capacitor reference voltage parameter and the capacitor real-time voltage parameter to obtain a first voltage parameter;
and if so, judging that the adjustment of the capacitor voltage parameter on the direct current side is finished.
Preferably, the adjusting module further includes an active power instruction unit, configured to determine whether the active power instruction parameter is zero before a first voltage parameter is obtained after the difference is made between the capacitor reference voltage parameter and the capacitor real-time voltage parameter;
if not, setting the active power instruction parameter to zero.
Preferably, the electrical signal parameters include a grid-connected point voltage per unit parameter, a grid-connected point bus voltage upper limit parameter, and a grid-connected point bus voltage lower limit parameter;
the reactive power module comprises a reactive power compensation unit, and the reactive power compensation unit is used for calculating by using a reactive power model to obtain a first reactive power compensation parameter according to the comparison result of the grid-connected point voltage per unit parameter and the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter; the reactive power model comprises the reactive compensation parameters;
and the reactive power control unit is used for processing the first reactive power compensation parameter by using a proportional-integral model to obtain the reactive power control parameter.
Preferably, the reactive compensation parameters comprise a reactive proportionality coefficient and rated current parameters of the energy storage type static synchronous compensator;
the reactive power compensation unit comprises a first subunit, and is used for calculating by using the reactive scaling factor, the grid-connected point bus voltage upper limit parameter, the grid-connected point voltage per unit parameter and the rated current parameter to obtain the first reactive power compensation parameter when the grid-connected point voltage per unit parameter is between the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter;
the second subunit is configured to, when the per-unit voltage parameter of the grid-connected point is smaller than the lower limit voltage parameter of the grid-connected point bus, calculate to obtain the first reactive power compensation parameter by using the rated current parameter and the per-unit voltage parameter of the grid-connected point;
and the third subunit is used for taking a preset fixed parameter as the first reactive power compensation parameter when the per-unit voltage parameter of the grid-connected point is greater than the upper limit voltage parameter of the grid-connected point bus.
Preferably, the reactive module further comprises a judging unit, configured to judge whether a shutdown angle of the converter valve on the inverter side decreases;
if so, acquiring a turn-off angle real-time parameter and a turn-off angle reference parameter of the turn-off angle of the converter valve;
the turn-off angle unit is used for obtaining a turn-off angle difference value parameter after the turn-off angle real-time parameter is differenced with the turn-off angle reference parameter;
the second reactive power compensation unit is used for processing the turn-off angle difference value parameter by using a proportional-integral model to obtain a second reactive power compensation parameter; the second reactive power compensation parameter is within the rated power range of the energy storage type static synchronous compensator;
and the parameter input unit is used for summing the first reactive power compensation parameter and the second reactive power compensation parameter to obtain a reactive power summation parameter, and processing the reactive power summation parameter by using the proportional-integral model to obtain the reactive power control parameter.
Preferably, when no ac fault occurs on the inverter side, the system further includes a first active power current unit configured to calculate a first active power current parameter based on the obtained active power instruction parameter, an inverter side bus voltage parameter, and a current proportionality coefficient;
the voltage amplitude bit unit is used for converting the obtained three-phase voltage parameters through coordinates to obtain voltage amplitude phase parameters;
the real-time frequency unit is used for processing the voltage amplitude phase parameter by utilizing a phase-locked loop circuit to obtain real-time frequency;
the difference frequency unit is used for obtaining difference frequency after the real-time frequency is different from the obtained rated frequency;
the second active power current unit is used for processing the difference frequency by using a proportional-integral model to obtain a second active power current parameter;
the active control unit is used for summing the first active power current parameter and the second active power current parameter to obtain an active power summing parameter, and processing the active power summing parameter by using the proportional-integral model to obtain an active control parameter;
the first reactive power current unit is used for calculating to obtain a reactive power current parameter based on the reactive instruction parameter, the inversion side bus voltage parameter and the current proportionality coefficient when receiving the reactive instruction parameter;
the first reactive driving unit is used for processing the reactive power current parameter by using the proportional-integral model to obtain a reactive driving parameter;
the alternating voltage instruction single member is used for acquiring the real-time voltage parameter of the alternating current bus and the reference voltage parameter of the alternating current bus when receiving the alternating voltage instruction;
and the second reactive power current unit is used for subtracting the real-time voltage parameter of the alternating current bus from the reference voltage parameter of the alternating current bus to obtain an alternating current bus voltage difference value parameter, and processing the alternating current bus voltage difference value parameter by using the proportional-integral model to obtain the reactive power driving parameter.
In a third aspect:
a weak receiving end HVDC system commutation fault suppression device comprises a storage and a processor, wherein the storage stores a weak receiving end HVDC system commutation fault suppression method, and the processor is used for adopting the method when executing the weak receiving end HVDC system commutation fault suppression method.
In a fourth aspect:
a storage medium storing a computer program that can be loaded by a processor and that executes the method described above.
The embodiment of the invention has the following beneficial effects:
the reactive power control parameters are calculated by utilizing the reactive power compensation parameters and the electric signal parameters of the grid-connected point, and the reactive power output by the energy storage type static synchronous compensator is changed through the reactive power control parameters, so that the reactive power of the inversion side of the weak receiving end HVDC system is influenced, and the probability of commutation failure is reduced; meanwhile, the target voltage parameter is utilized to adjust the capacitor voltage parameter of the direct current side of the energy storage type static synchronous compensator, so that the stability of the capacitor voltage parameter is improved, the fluctuation of the capacitor voltage parameter is reduced, and the operation stability of the weak receiving end HVDC system is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Wherein:
fig. 1 is a flowchart of a method for suppressing a commutation fault of a weak receiving-end HVDC system in one embodiment.
FIG. 2 is a schematic diagram of a topology of an energy storage type static synchronous compensator according to an embodiment.
Fig. 3 is a block diagram of active power control during an inverter side fault of a weak receiving-end HVDC system commutation fault suppression method in one embodiment.
Fig. 4 is a reactive power control block diagram in the event of an inverter side fault in a weak receiving-end HVDC system commutation fault suppression method in one embodiment.
Fig. 5 is a block diagram of active power control when the inversion side of a weak receiving-end HVDC system commutation fault suppression method is faultless in one embodiment.
Fig. 6 is a reactive power control block diagram of the weak receiving-end HVDC system when the inverter side has no fault according to the commutation fault suppression method in one embodiment.
Fig. 7 is a block diagram of a commutation fault suppression system of a weak receiving-end HVDC system in one embodiment.
Fig. 8 is a schematic structural diagram of a commutation fault suppression device of a weak receiving end HVDC system in one embodiment.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.
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 invention belongs. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to be limiting of the invention.
Before further detailed description of the embodiments of the present invention, terms and expressions referred to in the embodiments of the present invention are described, and the terms and expressions referred to in the embodiments of the present invention are applicable to the following explanations.
Weak receiving end: when the short circuit ratio SCR of a receiving end alternating current system in the direct current transmission system is less than 3, the receiving end is judged to be weak, and the receiving end is called as a weak receiving end. Wherein, SCR refers to the ratio of the short-circuit capacity of the alternating current system to the rated transmission power of direct current.
HVDC (High Voltage Direct Current): high voltage direct current.
The embodiment of the application discloses a method for suppressing a commutation fault of a weak receiving-end HVDC system, as shown in FIG. 1, the method comprises the following steps:
s101, when an alternating current fault occurs on an inversion side, obtaining reactive compensation parameters, electric signal parameters of a grid connection point and target voltage parameters of an energy storage type static synchronous compensator corresponding to a direct current side.
The weak receiving end HVDC system comprises a transmitting end and a weak receiving end, and direct current reaches the weak receiving end from the transmitting end through a power transmission line. The weak receiving end comprises an inversion side; the inversion side is the inversion station. In the weak receiving end HVDC system, a fault monitoring system is preset, and in one embodiment, whether an alternating current fault occurs on an inverter side is judged according to a detection result output by the fault monitoring system. In an application scenario, an ac fault refers to a ground fault.
In one embodiment, the topology of the energy storage static synchronous compensator (STATCOM/BESS) is shown in FIG. 2, and includes a DC-DC module and a DC-AC module. The DC-DC module is a direct current side, and the two groups of storage batteries are connected in parallel to a capacitor C at the direct current side through a bidirectional Buck-Boost converter dc (ii) a The DC-AC module adopts a three-phase two-level DC-AC converter and is merged into a power grid through an R-L filter. In one embodiment, the reactive compensation parameter, the electric signal parameter and the target voltage parameter are obtained by a preset current sensor and/or a preset voltage sensor. In another embodiment, the reactive compensation parameter, the electrical signal parameter and the target voltage parameter may include preset parameter values, i.e. preset values, when the preset parameter values are called up to a preset storage path or a database in addition to passing through the current sensor and/or the voltage sensor to obtain the reactive compensation parameter, the electrical signal parameter and the target voltage parameter.
And the grid-connected point refers to the position of the STATCOM connected to the AC bus of the inverter side.
And S102, calculating reactive control parameters according to the reactive compensation parameters and the electric signal parameters.
After the inverter side has a ground fault, the inverter side voltage is maintained by controlling the energy storage type static synchronous compensator to inhibit the occurrence of a phase change fault. After the reactive control parameters are obtained according to the reactive compensation parameters and the electric signal parameters, the reactive control parameters are used as driving signals of the pulse modulation circuit to control the on and/or off of the IGBT in the energy storage type static synchronous compensator to send out reactive power, and the purpose of maintaining the voltage of the inverter side is achieved.
And S103, driving the energy storage type static synchronous compensator based on the reactive control parameter, and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault.
In one embodiment, the capacitor voltage parameter is adjusted by the target voltage parameter, so that the oscillation of the direct-current side voltage is reduced, the capacitor voltage parameter is stabilized, and the purpose of improving the running stability of the weak receiving-end HVDC system while suppressing the commutation fault by using the reactive control parameter is achieved.
For further definition and illustration, in another embodiment of the present invention, as shown in fig. 3, the target voltage parameters include a real-time voltage parameter of a capacitor on the dc side of the energy storage type static synchronous compensator and a reference voltage parameter of the capacitor. The step of adjusting the capacitor voltage parameter on the dc side based on the target voltage parameter includes:
s201, obtaining a first voltage parameter by subtracting the capacitance reference voltage parameter and the capacitance real-time voltage parameter. In one embodiment, the capacitance reference voltage parameter is used
Figure BDA0003748885310000101
Representing the real-time voltage parameter of the capacitor by u dc Represents;
Figure BDA0003748885310000102
the real-time voltage parameter of the capacitor is shown in the circuit of FIG. 2 as capacitor C dc The current voltage value of. Capacitor C under the condition that the capacitance reference voltage parameter is normal dc Is a preset voltage value.
S202, processing the first voltage parameter by using a proportional-integral model to obtain an active current parameter.
In one embodiment, the proportional-integral model, i.e., the PI model, is located in the PI controller, and when the proportional-integral model needs to be used, the input parameters are input into the PI controller. In one embodiment, the active current parameter is I p And (4) showing.
And S203, taking the active current parameter as the input current of a preset driving circuit to obtain a capacitor voltage parameter.
In one embodiment, the driving circuit is used for modulating the internal power of the energy storage type static synchronous compensatorA circuit for switching on and off an electronic device belongs to an internal circuit of an energy storage type static synchronous compensator, such as a pulse trigger modulation circuit. U 'for capacitor voltage parameter' dc And (4) showing.
S204, judging whether the difference value of the capacitor voltage parameter and the capacitor reference voltage parameter meets a preset threshold condition.
In an embodiment, the difference between the capacitor voltage parameter and the capacitor reference voltage parameter is obtained and an absolute value is made, and the difference is compared with a threshold condition to determine whether the difference satisfies the threshold condition. In one embodiment, the threshold condition is a range of values, such as 0 to 1; and if the difference value is within the numerical range corresponding to the threshold condition, judging that the difference value meets the threshold condition, otherwise, judging that the difference value does not meet the threshold condition. In another embodiment, the threshold condition is a specific value, such as 0.5; and if the difference is smaller than the value corresponding to the threshold condition, judging that the difference meets the threshold condition, otherwise, judging that the difference does not meet the threshold condition.
And if the difference value between the capacitor voltage parameter and the capacitor reference voltage parameter does not meet the threshold condition, taking the capacitor voltage parameter as the capacitor real-time voltage parameter for iterative calculation.
The capacitance voltage parameter is a capacitance real-time voltage parameter, which is calculated as u' dc Is given to u dc . Then u is put dc The value of (2) is substituted into step S201, and then steps S202 to S204 are sequentially executed until the difference between the capacitor voltage parameter and the capacitor reference voltage parameter satisfies the threshold condition, the iteration is stopped, and it is determined that the adjustment of the capacitor voltage parameter on the dc side is completed.
The PI controller and the driving circuit are used for continuously optimizing the real-time voltage parameter of the capacitor to enable the real-time voltage parameter to be close to the reference voltage parameter of the capacitor, the purpose of stabilizing the voltage of the direct current side is achieved, the calculation process is simple, the phase change fault suppression cost is saved, and the stability of the weak receiving end HVDC system is improved when the suppression phase change failure occurs.
In another embodiment of the present invention, for further limitation and explanation, before the step of obtaining the first voltage parameter by subtracting the real-time voltage parameter of the capacitor from the reference voltage parameter of the capacitor, the method further includes:
s301, judging whether the active power instruction parameter is zero or not.
It should be noted that, in an embodiment, step S301 may be executed before S201, or may be executed before the target voltage parameter is acquired, that is, only after the ac fault occurs on the inverter side. The active power instruction parameter is a numerical value represented by an active power instruction, and when the inversion side of the weak receiving end HVDC system has no ground fault, namely the weak receiving end HVDC system is in a normal working condition state, the upper computer transmits the active power instruction to the current execution main body. And the current execution main body analyzes the active power instruction to obtain an active power instruction parameter. And then regulating and controlling an active power output value of the energy storage type static synchronous compensator according to the active power instruction parameter, and intervening the weak receiving end HVDC system.
In one embodiment, it is determined whether the latest received active power command parameter is zero. In another embodiment, it is determined whether the currently active power command parameters are all zero.
If the active power command parameter is not zero, step S302 is executed to set the active power command parameter to zero.
Specifically, the active power instruction parameter is set to zero, so that the influence of the active power output by the energy storage type static synchronous compensator according to the active power instruction parameter on the voltage parameter of the charge-regulating capacitor is reduced, and the stability, the regulation efficiency and the regulation quality of the voltage parameter of the capacitor are improved.
In another embodiment of the present invention, for further limitation and description, as shown in fig. 4, the electrical signal parameters include a per unit grid-connected point voltage parameter, a grid-connected point bus voltage upper limit parameter, and a grid-connected point bus voltage lower limit parameter. The step of calculating the reactive power control parameter according to the reactive power compensation parameter and the electric signal parameter comprises the following steps:
s401, according to the comparison result of the grid-connected point voltage per unit parameter and the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter, calculating by using a reactive power model to obtain a first reactive power compensation parameter.
The reactive power model comprises reactive compensation parameters. It should be noted that comparing the per-unit voltage parameter of the grid-connected point with the upper limit voltage parameter of the grid-connected point bus and the lower limit voltage parameter of the grid-connected point bus means comparing the per-unit voltage parameter of the grid-connected point with the upper limit voltage parameter of the grid-connected point bus and the lower limit voltage parameter of the grid-connected point bus respectively, and determining the size relationship between the three parameters. In an application scene, if the per-unit voltage parameter of the grid-connected point is greater than or equal to the upper limit voltage parameter of the grid-connected point bus, the comparison between the per-unit voltage parameter of the grid-connected point and the lower limit voltage parameter of the grid-connected point bus is not needed; similarly, if the per-unit grid-connected point parameter is less than or equal to the lower limit voltage parameter of the grid-connected point bus, the per-unit grid-connected point voltage parameter does not need to be compared with the upper limit voltage parameter of the grid-connected point bus.
In one embodiment, the per unit parameter of the voltage of the grid-connected point is v in Representing; q for first reactive power compensation parameter T And (4) showing.
S402, processing the first reactive power compensation parameter by using a proportional-integral model to obtain a reactive power control parameter.
And obtaining reactive control parameters by utilizing the proportional-integral model, the grid-connected point related voltage parameters and the reactive compensation parameters. And when the first reactive power compensation parameter is calculated, simple comparison action is carried out, and calculation can be carried out according to a preset reactive power model. The process is simple, manual participation is not needed, and the suppression cost of the commutation fault is reduced.
In another embodiment of the present invention, for further definition and explanation, the reactive compensation parameters include a reactive scaling factor and a rated current parameter of the energy storage type static synchronous compensator as shown in fig. 4. The method comprises the following steps of calculating by using a reactive power model to obtain a first reactive power compensation parameter according to a comparison result of a grid-connected point voltage per unit parameter, a grid-connected point bus voltage upper limit parameter and a grid-connected point bus voltage lower limit parameter, wherein the comparison result comprises the following steps:
and S501, when the per-unit voltage parameter of the grid-connected point is between the upper limit voltage parameter of the grid-connected point bus and the lower limit voltage parameter of the grid-connected point bus, calculating by using the reactive proportionality coefficient, the upper limit voltage parameter of the grid-connected point bus, the per-unit voltage parameter of the grid-connected point and the rated current parameter to obtain a first reactive power compensation parameter.
S502, when the per-unit voltage parameter of the grid-connected point is smaller than the lower limit voltage parameter of the grid-connected point bus, calculating by using the rated current parameter and the per-unit voltage parameter of the grid-connected point to obtain a first reactive power compensation parameter.
And S503, when the per-unit voltage parameter of the grid-connected point is greater than the upper limit voltage parameter of the grid-connected point bus, taking a preset fixed parameter as a first reactive power compensation parameter.
In one embodiment, the reactive power model is:
Figure BDA0003748885310000131
wherein Q is T A first reactive power compensation parameter; k is a radical of T1 Is a reactive proportionality coefficient; v. of max The grid connection point bus voltage upper limit parameter is obtained; v. of in The voltage per unit parameter of the grid-connected point is obtained; i is N Is a rated current parameter; v. of min And the lower limit parameter is the grid-connected point bus voltage. In the present embodiment, the fixed parameter is 0.
The reactive proportional coefficient and the rated current parameter are conveniently and quickly obtained, the calculation formula in the reactive power model is simple, the calculation complexity is reduced, and the calculation resources are saved.
In another embodiment of the present invention, for further definition and illustration, as shown in fig. 4, before the step of processing the first reactive power compensation parameter by using the proportional-integral model, the method further includes:
s601, judging whether the turn-off angle of the converter valve on the inversion side is reduced.
In one embodiment, the magnitude of the turn-off angle is monitored by a corresponding sensor to determine whether the turn-off angle has decreased.
S602, when the turn-off angle is reduced, obtaining a turn-off angle real-time parameter gamma and a turn-off angle reference parameter gamma of the turn-off angle of the converter valve * 。
In one embodiment, the turn-off angle real-time parameterγ can be obtained by a sensor or the like, or indirectly by calculation. Reference parameter gamma of turn-off angle * And (4) calling the target object to the specified path according to the preset value.
S603, enabling the real-time parameter gamma of the turn-off angle and the reference parameter gamma of the turn-off angle * And obtaining a difference value parameter of the turn-off angle after difference is made.
And S604, processing the turn-off angle difference parameter by using a proportional-integral model to obtain a second reactive power compensation parameter.
And the second reactive power compensation parameter is within the rated power range of the energy storage type static synchronous compensator. Specifically, the upper limit value of the rated power range is Qmax, and the lower limit value is-Qmax.
S605, compensating the first reactive power parameter Q T Summing the second reactive power compensation parameter to obtain a reactive power summation parameter, and processing the reactive power summation parameter by using a proportional integral model to obtain a reactive power control parameter I q 。
Calculation of reactive power control parameter I by the angle of cut-off q The method is convenient for inhibiting the occurrence of commutation failure to the maximum extent in a short time, and improves the inhibition efficiency and the inhibition quality. The calculation process is simple, manual participation is not needed, and the automation degree is high.
In another embodiment of the present invention, for further limitation and explanation, as shown in fig. 5, when no ac fault occurs on the inverter side, the method further includes:
s701, obtaining an active power instruction parameter P ref And the inverter side bus voltage parameter U Forehead (forehead) And calculating the current proportion coefficient to obtain a first active power current parameter.
In one embodiment, the active power command parameter P ref And the inverter side bus voltage parameter U Forehead (forehead) And the current proportionality coefficient is automatically obtained through a sensor or a preset path. Active power instruction parameter P ref And the voltage parameter U of the inversion side bus Forehead (forehead) The result of the division is used as an input parameter of the active power control module. The active power control module is a self-contained module in the energy storage type static synchronous compensator, and the current proportionality coefficient isThe coefficient in the power control module, in this embodiment, the current scaling coefficient is 0.6667, and the symbol in fig. 5 represents the multiplication with the current scaling coefficient. The first active power current parameter can be calculated by using the active power control module,
And S702, transforming the obtained three-phase voltage parameters through coordinates to obtain voltage amplitude phase parameters.
And S703, processing the voltage amplitude phase parameter by using a phase-locked loop circuit to obtain the real-time frequency omega.
The voltage amplitude phase parameters refer to the voltage amplitude and the phase of the three-phase voltage of the power grid. In one embodiment, a PLL refers to a phase-locked loop circuit. The real-time frequency refers to the voltage frequency of three-phase voltage of the power grid.
S704, comparing the real-time frequency omega with the obtained rated frequency omega * And obtaining difference frequency after difference.
Correspondingly, the nominal frequency refers to the nominal frequency of the three-phase voltage of the power grid.
S705, processing the difference frequency by using a proportional-integral model to obtain a second active power current parameter.
And S706, summing the first active power current parameter and the second active power current parameter to obtain an active power summing parameter, and processing the active power summing parameter by using the proportional-integral model to obtain an active control parameter.
Wherein the active control parameters refer to the drive signals in fig. 5. The active control parameter is used as the input parameter of the energy storage type static synchronous compensator, and the active power output value of the energy storage type static synchronous compensator can be changed.
Under normal working conditions, the energy storage type static synchronous compensator can be controlled to output active power, and the stability of the voltage of a power grid is improved.
In another embodiment of the present invention, for further limitation and explanation, as shown in fig. 6, when no ac fault occurs on the inverter side, the method further includes:
s801, receiving the reactive power instruction parameter Q ref Based on reactive command parameter Q ref And the inverter side bus voltage parameter U Forehead (forehead) And calculating the current proportion coefficient to obtain a reactive power current parameter.
It should be noted that, after the ac fault does not occur on the inverter side and the reactive command parameter is received, the reactive power current parameter is calculated.
Specifically, in an embodiment, the current scaling factor is a factor in a power control module of the energy storage type static synchronous compensator, and is 0.6667. The reactive power current parameter is calculated by firstly using a reactive instruction parameter Q ref Divided by the inverter side bus voltage parameter U Forehead (D) And obtaining a division result, using the division result as an input parameter of the power control module, and calculating to obtain a reactive power current parameter.
And S802, processing the reactive power current parameters by using a proportional-integral model to obtain reactive driving parameters.
Specifically, as shown in fig. 6, when the reactive instruction parameter is received, the upper layer instruction is the reactive instruction parameter, the switch moves up, and the calculation path located above is switched on, so as to output the reactive drive parameter, that is, the drive signal I q 。
The energy storage type static synchronous compensator is regulated and controlled through the driving signal, and reactive power output by the energy storage type static synchronous compensator is changed.
In another embodiment of the present invention, for further limitation and explanation, as shown in fig. 6, when no ac fault occurs on the inverter side, the method further includes:
s803, when the alternating voltage instruction is received, acquiring the real-time voltage parameter Vi of the alternating current bus n And AC bus reference voltage parameter
Figure BDA0003748885310000161
When the ac voltage command is received, it means that no ac fault occurs on the inverter side, and the reactive command parameter is received. Real-time voltage parameter V of alternating current bus in I.e. the real-time value of the per unit parameter of the point-to-point voltage.
S804, carrying out real-time voltage parameter V on the alternating current bus in Reference voltage parameter of AC bus
Figure BDA0003748885310000162
And performing subtraction to obtain an alternating current bus voltage difference value parameter, and processing the alternating current bus voltage difference value parameter by using a proportional-integral model to obtain a reactive power driving parameter.
Specifically, as shown in fig. 6, when the reactive power instruction parameter is received, the upper layer instruction is an ac voltage instruction, the switch is moved down, and the calculation path located below is switched on, so as to output the reactive power driving parameter, i.e., the driving signal I q 。
The method comprises the steps that under a normal working condition, a constant reactive power control mode and a constant alternating voltage control mode are included, and when real-time voltage parameters of an alternating current bus do not fluctuate, the constant reactive power control mode is adopted to receive reactive power instruction parameters; and when the real-time voltage parameter of the alternating current bus fluctuates, a constant alternating current voltage control mode is adopted to receive an alternating current voltage instruction. The control flexibility is improved, and the alternating current bus voltage is stabilized, so that the power grid is stabilized.
Firstly, an energy storage type static synchronous compensator is selected as a compensator in a weak receiving end HVDC system and used for inhibiting commutation failure and improving the stability of the system. Secondly, after the inverter side fails, the energy storage type static synchronous compensator is driven to adjust the reactive power by outputting reactive control parameters, and the phase change failure is restrained; meanwhile, consideration factors of the turn-off angle are added, and the suppression efficiency and effect are improved by using the related parameters of the turn-off angle. In addition, when reactive compensation is carried out, the capacitor voltage on the direct current side is stabilized according to the target voltage parameter on the direct current side of the energy storage type static synchronous compensator, voltage fluctuation on the direct current side is reduced, and the stability of the system is further improved.
The embodiment of the present application further discloses a weak receiving-end HVDC system commutation fault suppression system, as shown in fig. 7, including:
the acquisition module 1 is used for acquiring reactive compensation parameters and electric signal parameters of a grid connection point and target voltage parameters of the energy storage type static synchronous compensator corresponding to a direct current side when an alternating current fault occurs on an inversion side after the alternating current fault occurs on the inversion side;
the reactive power module 2 is used for calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters;
and the adjusting module 3 is used for driving the energy storage type static synchronous compensator based on the reactive control parameter and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault.
Preferably, the target voltage parameter includes a capacitance real-time voltage parameter and a capacitance reference voltage parameter at the dc side;
the adjusting module comprises a first voltage unit, and is used for obtaining a first voltage parameter after the difference is made between the capacitor reference voltage parameter and the capacitor real-time voltage parameter;
the active current unit is used for processing the first voltage parameter by using a proportional-integral model to obtain an active current parameter;
the capacitor voltage unit is used for taking the active current parameter as the input current of a preset driving circuit to obtain the capacitor voltage parameter;
the threshold condition unit is used for judging whether the difference value of the capacitor voltage parameter and the capacitor reference voltage parameter meets a preset threshold condition or not;
if not, taking the capacitor voltage parameter as the capacitor real-time voltage parameter, and executing the step to make a difference between the capacitor reference voltage parameter and the capacitor real-time voltage parameter to obtain a first voltage parameter;
and if so, judging that the adjustment of the capacitor voltage parameter on the direct current side is finished.
Preferably, the adjusting module further includes an active power instruction unit, configured to determine whether the active power instruction parameter is zero before a first voltage parameter is obtained after the difference is made between the capacitor reference voltage parameter and the capacitor real-time voltage parameter;
if not, setting the active power instruction parameter to zero.
Preferably, the electrical signal parameters include a grid-connected point voltage per unit parameter, a grid-connected point bus voltage upper limit parameter, and a grid-connected point bus voltage lower limit parameter;
the reactive power module comprises a reactive power compensation unit and is used for calculating by using a reactive power model to obtain a first reactive power compensation parameter according to a comparison result of the grid-connected point voltage per unit parameter, the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter; the reactive power model comprises the reactive compensation parameters;
and the reactive power control unit is used for processing the first reactive power compensation parameter by using a proportional-integral model to obtain the reactive power control parameter.
Preferably, the reactive compensation parameters comprise a reactive proportionality coefficient and rated current parameters of the energy storage type static synchronous compensator;
the reactive power compensation unit comprises a first subunit, and is used for calculating by using the reactive scaling factor, the grid-connected point bus voltage upper limit parameter, the grid-connected point voltage per unit parameter and the rated current parameter to obtain the first reactive power compensation parameter when the grid-connected point voltage per unit parameter is between the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter;
the second subunit is used for calculating to obtain the first reactive power compensation parameter by using the rated current parameter and the per-unit voltage parameter of the grid-connected point when the per-unit voltage parameter of the grid-connected point is smaller than the lower limit parameter of the bus voltage of the grid-connected point;
and the third subunit is used for taking a preset fixed parameter as the first reactive power compensation parameter when the per-unit voltage parameter of the grid-connected point is greater than the upper limit voltage parameter of the grid-connected point bus.
Preferably, the reactive power module further comprises a judging unit, configured to judge whether a turn-off angle of the converter valve on the inverter side decreases;
if so, acquiring a turn-off angle real-time parameter and a turn-off angle reference parameter of the turn-off angle of the converter valve;
the turn-off angle unit is used for obtaining a turn-off angle difference value parameter after the turn-off angle real-time parameter is differenced with the turn-off angle reference parameter;
the second reactive power compensation unit is used for processing the turn-off angle difference value parameter by using a proportional-integral model to obtain a second reactive power compensation parameter; the second reactive power compensation parameter is within the rated power range of the energy storage type static synchronous compensator;
and the parameter input unit is used for summing the first reactive power compensation parameter and the second reactive power compensation parameter to obtain a reactive power summation parameter, and processing the reactive power summation parameter by using the proportional-integral model to obtain the reactive power control parameter.
Preferably, when no ac fault occurs on the inverter side, the system further includes a first active power current unit configured to calculate a first active power current parameter based on the obtained active power instruction parameter, an inverter side bus voltage parameter, and a current proportionality coefficient;
the voltage amplitude bit unit is used for converting the obtained three-phase voltage parameters through coordinates to obtain voltage amplitude phase parameters;
the real-time frequency unit is used for processing the voltage amplitude phase parameter by utilizing a phase-locked loop circuit to obtain real-time frequency;
the difference frequency unit is used for obtaining difference frequency after the real-time frequency is different from the obtained rated frequency;
the second active power current unit is used for processing the difference frequency by using a proportional-integral model to obtain a second active power current parameter;
the active control unit is used for summing the first active power current parameter and the second active power current parameter to obtain an active power summing parameter, and processing the active power summing parameter by using the proportional-integral model to obtain an active control parameter;
the first reactive power current unit is used for calculating to obtain a reactive power current parameter based on the reactive instruction parameter, the inversion side bus voltage parameter and the current proportionality coefficient when receiving the reactive instruction parameter;
the first reactive driving unit is used for processing the reactive power current parameters by utilizing the proportional-integral model to obtain reactive driving parameters;
the alternating voltage instruction single member is used for acquiring the real-time voltage parameter of the alternating current bus and the reference voltage parameter of the alternating current bus when receiving the alternating voltage instruction;
and the second reactive power current unit is used for subtracting the real-time voltage parameter of the alternating current bus from the reference voltage parameter of the alternating current bus to obtain an alternating current bus voltage difference value parameter, and processing the alternating current bus voltage difference value parameter by using the proportional-integral model to obtain the reactive power driving parameter.
Here, it should be noted that: the above description applied to the phase change fault suppression system embodiment of the weak receiving end HVDC system is similar to the above description of the method, and has the same beneficial effects as the method embodiment. For technical details not disclosed in the embodiments of the commutation fault suppression system of the weakly receiving HVDC system of the invention, a person skilled in the art will understand with reference to the description of the embodiments of the method of the invention.
It should be noted that, in the embodiment of the present invention, if the method is implemented in the form of a software functional module and sold or used as a standalone product, it may also be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present invention may be essentially implemented or a part contributing to the prior art may be embodied in the form of a software product, which is stored in a storage medium and includes several 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 methods described in the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read Only Memory (ROM), a magnetic disk, or an optical disk, and various media capable of storing program codes. Thus, embodiments of the invention are not limited to any specific combination of hardware and software.
Correspondingly, the embodiment of the application also discloses a storage medium which stores a computer program capable of being loaded by a processor and executing the method.
The embodiment of the application also discloses a device for suppressing the commutation fault of the weak receiving-end HVDC system, which is shown in fig. 8 and comprises a processor 100, at least one communication bus 200, a user interface 300, at least one external communication interface 400 and a memory 500. Wherein the communication bus 200 is configured to enable connective communication between these components. Where the user interface 300 may include a display screen and the external communication interface 400 may include standard wired and wireless interfaces. The storage 500 stores therein a method for suppressing a commutation fault of the weak receiving-end HVDC system. Wherein the processor 100 is configured to employ the above-described method in performing the weak receive-side HVDC system commutation fault suppression method stored in the memory 500.
The above description applied to the commutation fault suppression device and storage medium embodiments of the weak receiving end HVDC system is similar to the description of the method embodiments described above, and has similar beneficial effects as the method embodiments. For technical details not disclosed in embodiments of the weak receiver HVDC system commutation fault suppression device and storage medium according to the present invention, reference is made to the description of embodiments of the method according to the present invention for understanding.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a component of' 8230; \8230;" does not exclude the presence of another like element in a process, method, article, or apparatus that comprises the element.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described device embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between the devices or units may be electrical, mechanical or in other forms.
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; can be located in one place or 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, all the functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately regarded as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit.
Those of ordinary skill in the art will understand that: all or part of the steps for realizing the method embodiments can be completed by hardware related to program instructions, the program can be stored in a computer readable storage medium, and the program executes the steps comprising the method embodiments when executed; and the aforementioned storage medium includes: a removable storage device, a ROM, a magnetic or optical disk, or other various media that can store program code.
Alternatively, the integrated unit of the present invention may be stored in a computer-readable storage medium if it is implemented in the form of a software functional module and sold or used as a separate product. Based on such understanding, the technical solutions of the embodiments of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a device to perform all or part of the methods according to the embodiments of the present invention. And the aforementioned storage medium includes: a removable storage device, a ROM, a magnetic or optical disk, or other various media that can store program code.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (10)

1. A weak receiving end HVDC system commutation fault suppression method is characterized by comprising the following steps:
when an alternating current fault occurs on the inversion side, acquiring reactive compensation parameters, electric signal parameters of a grid connection point and target voltage parameters of the energy storage type static synchronous compensator corresponding to the direct current side;
calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters;
and driving the energy storage type static synchronous compensator based on the reactive control parameter, and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault.
2. The weak receive-end HVDC system commutation fault suppression method of claim 1, wherein said target voltage parameters comprise a capacitive real-time voltage parameter and a capacitive reference voltage parameter at said dc side;
the step of adjusting the capacitor voltage parameter on the dc side based on the target voltage parameter comprises:
obtaining a first voltage parameter by subtracting the capacitance reference voltage parameter from the capacitance real-time voltage parameter;
processing the first voltage parameter by using a proportional-integral model to obtain an active current parameter;
taking the active current parameter as the input current of a preset drive circuit to obtain the capacitor voltage parameter;
judging whether the difference value of the capacitor voltage parameter and the capacitor reference voltage parameter meets a preset threshold condition or not;
if not, taking the capacitor voltage parameter as the capacitor real-time voltage parameter, and executing the step to make a difference between the capacitor reference voltage parameter and the capacitor real-time voltage parameter to obtain a first voltage parameter;
and if so, judging that the adjustment of the capacitor voltage parameter on the direct current side is finished.
3. The method for suppressing commutation fault of a weak receiving-end HVDC system of claim 2, wherein before the step of obtaining the first voltage parameter by subtracting the capacitance reference voltage parameter from the capacitance real-time voltage parameter, the method further comprises:
judging whether the active power instruction parameter is zero or not;
if not, setting the active power instruction parameter to zero.
4. The weak receiving-end HVDC system commutation fault suppression method of claim 1, wherein the electrical signal parameters include a point-to-point voltage per unit parameter, a point-to-point bus voltage upper limit parameter, and a point-to-point bus voltage lower limit parameter;
the step of calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters comprises:
according to the comparison result of the grid-connected point voltage per unit parameter and the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter, calculating by using a reactive power model to obtain a first reactive power compensation parameter; the reactive power model comprises the reactive compensation parameters;
and processing the first reactive power compensation parameter by using a proportional-integral model to obtain the reactive power control parameter.
5. The weak receive-end HVDC system commutation fault suppression method of claim 4, wherein the reactive compensation parameters include a reactive scaling factor and a rated current parameter of the energy-storage static synchronous compensator;
the step of obtaining a first reactive power compensation parameter by utilizing reactive power model calculation according to the comparison result of the grid-connected point voltage per unit parameter, the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter comprises the following steps:
when the grid-connected point voltage per unit parameter is located between the grid-connected point bus voltage upper limit parameter and the grid-connected point bus voltage lower limit parameter, calculating by using the reactive scaling factor, the grid-connected point bus voltage upper limit parameter, the grid-connected point voltage per unit parameter and the rated current parameter to obtain the first reactive power compensation parameter;
when the per-unit voltage parameter of the grid-connected point is smaller than the lower limit voltage parameter of the grid-connected point bus, calculating by using the rated current parameter and the per-unit voltage parameter of the grid-connected point to obtain the first reactive power compensation parameter;
and when the per-unit voltage parameter of the grid-connected point is greater than the upper limit voltage parameter of the grid-connected point bus, taking a preset fixed parameter as the first reactive power compensation parameter.
6. The weak receiver HVDC system commutation fault suppression method of claim 4 or 5, wherein prior to said processing said first reactive power compensation parameter using a proportional-integral model, further comprising:
judging whether the turn-off angle of the converter valve on the inversion side is reduced or not;
if so, acquiring a turn-off angle real-time parameter and a turn-off angle reference parameter of the turn-off angle of the converter valve;
obtaining a turn-off angle difference parameter by subtracting the turn-off angle real-time parameter from the turn-off angle reference parameter;
processing the turn-off angle difference value parameter by using a proportional-integral model to obtain a second reactive power compensation parameter; the second reactive power compensation parameter is within the rated power range of the energy storage type static synchronous compensator;
and summing the first reactive power compensation parameter and the second reactive power compensation parameter to obtain a reactive power summation parameter, and processing the reactive power summation parameter by using the proportional-integral model to obtain the reactive power control parameter.
7. The weak receiving end HVDC system commutation fault suppression method of claim 1, wherein when no AC fault occurs on the inverting side, a first active power current parameter is calculated based on the obtained active power command parameter, an inverting side bus voltage parameter and a current proportionality coefficient;
transforming the obtained three-phase voltage parameters through coordinates to obtain voltage amplitude phase parameters;
processing the voltage amplitude phase parameter by using a phase-locked loop circuit to obtain real-time frequency;
obtaining difference frequency after the real-time frequency is different from the obtained rated frequency;
processing the difference frequency by using a proportional-integral model to obtain a second active power current parameter;
summing the first active power current parameter and the second active power current parameter to obtain an active power summing parameter, and processing the active power summing parameter by using the proportional-integral model to obtain an active control parameter;
when a reactive power instruction parameter is received, calculating to obtain a reactive power current parameter based on the reactive power instruction parameter, the inversion side bus voltage parameter and the current proportion coefficient;
processing the reactive power current parameter by using the proportional-integral model to obtain a reactive driving parameter;
when an alternating current voltage instruction is received, acquiring an alternating current bus real-time voltage parameter and an alternating current bus reference voltage parameter;
and subtracting the real-time voltage parameter of the alternating-current bus from the reference voltage parameter of the alternating-current bus to obtain a voltage difference value parameter of the alternating-current bus, and processing the voltage difference value parameter of the alternating-current bus by using the proportional-integral model to obtain the reactive power driving parameter.
8. A weak receive end HVDC system commutation fault suppression system, comprising:
the acquisition module is used for acquiring reactive compensation parameters, electric signal parameters of a grid connection point and target voltage parameters of the energy storage type static synchronous compensator corresponding to the direct current side when the alternating current fault occurs on the inversion side;
the reactive power module is used for calculating reactive power control parameters according to the reactive power compensation parameters and the electric signal parameters;
and the adjusting module is used for driving the energy storage type static synchronous compensator based on the reactive control parameter and adjusting the capacitor voltage parameter of the direct current side based on the target voltage parameter so as to suppress the commutation fault.
9. A weak receive-side HVDC system commutation fault suppression apparatus comprising a memory having stored therein a weak receive-side HVDC system commutation fault suppression method, and a processor for employing the method of any one of claims 1-7 when executing the weak receive-side HVDC system commutation fault suppression method.
10. A storage medium storing a computer program which can be loaded by a processor and which executes the method according to any one of claims 1 to 7.
CN202210832181.9A 2022-07-15 2022-07-15 Commutation fault suppression method, system, device and storage medium for weak receiving end HVDC system Pending CN115189389A (en)

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