CN114400695B - Control method and system of alternating current energy consumption device for flexible direct current system - Google Patents

Control method and system of alternating current energy consumption device for flexible direct current system Download PDF

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CN114400695B
CN114400695B CN202111570775.9A CN202111570775A CN114400695B CN 114400695 B CN114400695 B CN 114400695B CN 202111570775 A CN202111570775 A CN 202111570775A CN 114400695 B CN114400695 B CN 114400695B
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energy consumption
alternating current
converter station
current energy
consumption device
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CN114400695A (en
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郭铭群
李敬如
梅念
董力通
王海猷
佟宇梁
陈钊
史原通
邹格
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State Grid Economic And Technological Research Institute Co LtdB412 State Grid Office
State Grid Corp of China SGCC
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State Grid Economic And Technological Research Institute Co LtdB412 State Grid Office
State Grid Corp of China SGCC
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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
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
    • 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
    • H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
    • H02J13/00006—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
    • 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
    • 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
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
    • 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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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Rectifiers (AREA)

Abstract

The invention relates to a method and a system for controlling an alternating current energy consumption device for a flexible direct current system, wherein the method comprises the following steps: monitoring a positive locking signal, a negative locking signal, a positive direct current port voltage and a negative direct current port voltage of a new energy electric field island access converter station in real time, and judging the type of surplus power problem according to a monitoring result; and calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type, and dynamically adjusting the initial input group number according to the actual operation data of the converter station until the fault ride-through of the direct current system is successful. By adopting the method for adjusting the alternating current energy consumption device, the input group number of the alternating current energy consumption device can be automatically calculated and adjusted according to the electric quantity of the converter station where the alternating current energy consumption device is located, and the problem of failure in fault ride-through of a flexible direct current system caused by inaccurate information transmission outside the station is solved; and low disturbance fault ride-through of the flexible direct current system is realized, so that the flexible direct current system can be widely applied to the field of flexible direct current transmission.

Description

Control method and system of alternating current energy consumption device for flexible direct current system
Technical Field
The invention relates to a control method and a control system of an alternating current energy consumption device for a flexible direct current system, and belongs to the field of flexible direct current power transmission.
Background
The high-capacity flexible direct current system can not only exert the technical advantages of flexible direct current in development and utilization of new energy, but also realize multi-power supply and multi-drop power receiving, effectively stabilize the power fluctuation of the new energy, provide better channel redundancy and power supply reliability, and form an energy internet with various forms and flexible and complementary energy.
A typical wiring schematic diagram of a new energy electric field island access flexible direct current system is shown in fig. 1. When the new energy electric field island is connected into the flexible direct current system, due to the fact that voltage and current development speed of the flexible direct current system are difficult to match with the time of cutting off the new energy unit through the alternating current safety control device after the flexible direct current system fails, particularly under the condition that the new energy island is connected with full power, any alternating current and direct current failure can cause temporary surplus power of the flexible direct current system, and the flexible direct current system is broken down due to overvoltage and overcurrent. According to the surplus power characteristics of the flexible direct current system, the surplus power problem of the flexible direct current system can be divided into a first kind of surplus power problem and a second kind of surplus power problem. The first surplus power problem is mainly characterized in that the converter station is overcurrent and is mainly caused by locking of a sending end converter station; the second type of surplus power problem is mainly characterized by overvoltage of a direct current port, and is mainly caused by faults of a receiving-end alternating current power grid, locking of a receiving-end converter station and the like.
In order to realize fault ride-through of a new energy electric field island access flexible direct current system, alternating current energy consumption devices are configured in all sending end converter stations of the new energy electric field island access, and a wiring schematic diagram of a typical alternating current energy consumption device is shown in fig. 2. The control method of the existing alternating current energy consumption device comprises the following steps: 1. aiming at the first type of surplus power problem, according to a pole blocking signal of a sending end converter station and fault pole grid power, inputting an alternating current energy consumption device matched with the surplus power, and quitting the alternating current energy consumption devices with corresponding groups according to a new energy generator tripping signal; 2. aiming at the second type of surplus power problem, considering that a communication system usually has no time to transmit surplus power information to a sending end, an alternating current energy consumption device matched with overvoltage grid-connected power before a fault is input according to the overvoltage grid-connected power and the overvoltage grid-connected characteristic of a direct current port of a sending end converter station, and the alternating current energy consumption device is quitted according to a direct current overvoltage return signal.
However, the control method of the ac energy consumption device in the prior art mainly has the following problems: 1. aiming at the surplus power problem caused by the fault of the sending end converter station, the control method depends on the switch deflection information corresponding to the new energy generator tripping, so that not only is the additional investment of a communication system brought, but also when the switch deflection information corresponding to the new energy generator tripping is inaccurate, the wrong surplus power information can cause the fault ride-through failure of the flexible direct current system. 2. Aiming at the surplus power problem caused by the fault of the receiving end, when the power of the flexible direct current system is high and the surplus power is low, the alternating current energy consumption devices matched with the power of the overvoltage grid before the fault are all put into use, and large disturbance is caused to the flexible direct current system and the alternating current power grid of the receiving end.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a method and a system for controlling an ac energy consuming device for a flexible dc system, which can solve the problems of the existing control methods, and are a good-economical, low-disturbance fault ride-through scheme for the flexible dc system.
In order to achieve the purpose, the invention adopts the following technical scheme:
a control method of an alternating current energy consumption device for a flexible direct current system comprises the following steps:
monitoring a positive locking signal, a negative locking signal, a positive direct current port voltage and a negative direct current port voltage of a new energy electric field island access converter station in real time, and judging the type of surplus power problem according to a monitoring result;
and calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type, and dynamically adjusting the initial input group number according to actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful.
Further, the method for judging the surplus power problem type according to the monitoring result comprises the following steps:
if positive blocking signal or negative blocking signal B of converter station i ij If the power is suddenly changed from 0 to 1, judging the power is a first surplus power problem;
if in the time interval Δ t d At any time, the voltage of the positive electrode actual measurement direct current port of the converter station i or the voltage U of the negative electrode actual measurement direct current port ij Is greater than the input threshold voltage U of the AC energy consumption device in Judging the power surplus problem as a second type, wherein j =1,2;1 represents a positive electrode, and 2 represents a negative electrode.
Further, the method for calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type and dynamically adjusting the initial input group number according to the actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful comprises the following steps:
if the type is the first surplus power problem, calculating a first initial input group number of the alternating current energy consumption device according to the initial surplus power and rated active power consumed by a single group of alternating current energy consumption devices, and dynamically adjusting the first initial input group number according to actual measurement direct current port voltage and actual measurement active power of a sound and full pole of the converter station until the fault ride-through of the flexible direct current system is successful;
if the type is the second surplus power problem, calculating a second initial input group number of the alternating current energy consumption device according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage electrode on-line power before the fault, and dynamically adjusting the second initial input group number according to the actually measured direct current port voltage of the overvoltage electrode of the converter station until the fault ride-through of the flexible direct current system is successful.
Further, in the first type of surplus power problem, a method for calculating a first initial input group number of the alternating current energy consumption device according to the initial surplus power and rated active power consumed by the single group of alternating current energy consumption devices includes:
according to the initial active power P of the positive pole and the negative pole of the converter station i before the fault occurs 0ij Rated active power P of positive pole and negative pole of converter station i Nij Positive and negative blocking signals B of the converter station i ij Calculating to obtain the initial surplus power delta P i0 ；
According to initial surplus power delta P i0 Rated active power P consumed by single-group alternating current energy consumption device of converter station i cNi Calculating to obtain the first initial input group number N of the alternating current energy consumption device i0 。
Further, the method for dynamically adjusting the first initial input group number according to the actually measured dc port voltage and the actually measured active power of the healthy pole of the converter station includes:
after the alternating current energy consumption device is put into or quit the operation execution,
firstly, judging whether the voltage of an actually measured direct current port and the actually measured active power of an i sound pole of the converter station meet the conditions of each preset alternating current energy consumption device or not: if the conditions for casting a single group of alternating current energy consumption devices are met, delta t is set every time interval c The number of the input groups of the alternating current energy consumption devices is increased by 1; if the condition of the single group of the alternating current energy consumption devices is met, delta t is set every time interval c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group; otherwise, keeping the current state;
then, whether the current time reaches t is judged 0 +Δt 1 Time: if not, repeating the previous step; if the moment is reached, putting the alternating current energy consumption devices of the converter station i into the group number for zero clearing, and clearing the positive pole or negative pole locking signal for zero clearing, wherein t 0 Is the initial input time of the 1 st group of AC energy consumption devices, delta t 1 The longest allowable input time period is the longest of the alternating current energy consumption devices.
Further, the conditions of the single group of alternating current energy consumption devices are as follows: at time interval Deltat c At any time in the period, the voltage of the actually measured direct current port of the healthy pole of the converter station i is larger than the difference between the input threshold voltage of the alternating current energy consumption device and the deviation of the direct current voltage, or the actually measured active power of the healthy pole of the converter station i exceeds the allowable overload power;
the conditions for withdrawing the single-group alternating current energy consumption device are as follows: at a time interval Δ t c At any time in the period, the voltage of an actually measured direct current port of the healthy pole of the converter station i is lower than the highest steady-state direct current voltage, and the online power of the healthy pole of the converter station i after the single group of alternating current energy consumption devices are estimated to be smaller than the rated active power of the healthy pole of the converter station i.
The method for calculating the second initial input group number of the alternating current energy consumption device according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage power before the fault comprises the following steps:
according to the measured DC port voltage U of the overvoltage electrode of the converter station i ij From steady state maximum DC voltage U dmax Developing to the input threshold voltage U of the AC energy consumption device in Time period Δ t of ij The number n of positive or negative single bridge arm sub-modules corresponding to overvoltage electrodes in the operation current station ij And the capacitance value C of the individual sub-module capacitors 0ij Calculating the current surplus power delta P of the overvoltage electrode of the converter station i ij ；
According to the initial active power of the anode or the cathode of the converter station i before the fault occurs and the overvoltage signal O of the anode or the cathode of the converter station i ij Rated active power P consumed by single-group alternating current energy consumption device cNi And calculating the input group number N of the alternating current energy consumption devices matched with the overvoltage grid power before the fault ijmax ；
According to the current surplus power delta P of the overvoltage electrode of the converter station i ij Rated active power P consumed by single-group alternating current energy consumption device cNi And the input group number N of the alternating current energy consumption devices matched with the overvoltage grid power before the fault ijmax Calculating to obtain a second initial input group number N of the alternating current energy consumption device ij0 。
Further, the method for dynamically adjusting the second initial input group number according to the actually measured dc port voltage of the overvoltage electrode of the converter station includes:
after the AC energy consumption device is put into or quit the operation execution, whether the actually measured DC port voltage of the overvoltage electrode at the current moment meets the conditions of each AC energy consumption device is judged:
if the condition of over-throwing the AC energy consumption device is met, the number of groups thrown by the AC energy consumption device is increased by N ijmax -N ij Making the total input number reach N ijmax (ii) a Wherein N is ij The current input group number of the i pole j alternating current energy consumption device of the converter station is set;
if the conditions of throwing a single group of alternating current energy consumption devices are met, delta t is set at intervals c The number of the input groups of the alternating current energy consumption devices is increased by 1;
if the condition of the single group of the alternating current energy consumption devices is met, delta t is set every time interval c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group;
if the conditions of exiting all the alternating current energy consumption devices are met, clearing the overvoltage signals of the positive electrode or the negative electrode of the converter station, namely O i1 =0 or O i2 =0, and the number of groups of the AC energy consumption devices is reset;
otherwise, keeping the number of the input groups unchanged.
Further, the over-throw alternating current energy consumption device conditions are as follows: at time interval Deltat c At any time, the actually measured direct current port voltage of the overvoltage electrode of the converter station i is larger than the high voltage limit value U of the direct current system lim ；
The conditions of the single-group AC energy consumption device are as follows: at time interval Deltat c At any time in the converter station, when the voltage of the measured direct current port U of the overvoltage electrode of the converter station i is over ij Are all larger than the input threshold voltage U of the alternating current energy consumption device in Difference from the dc voltage deviation Δ U; the conditions for withdrawing the single-group alternating current energy consumption device are as follows: at a time interval Δ t c At any time in the converter station, when the voltage of the measured direct current port U of the overvoltage electrode of the converter station i is over ij Are all lower than the sum of the steady-state maximum direct-current voltage and the direct-current voltage deviation;
the conditions for withdrawing all the alternating current energy consumption devices are as follows: at time interval Deltat d At any time in the converter station, the measured DC port of the overvoltage electrode of the converter station iThe voltage is less than the exit threshold voltage U of the AC energy dissipation device out 。
The invention also provides a control system of the alternating current energy consumption device for the flexible direct current system, which comprises the following components:
the surplus power type judgment module is used for monitoring a positive blocking signal, a negative blocking signal, a positive direct-current port voltage and a negative direct-current port voltage of a new energy electric field island access converter station in real time and judging the type of surplus power problem according to a monitoring result;
and the input group number adjusting module of the alternating current energy consumption device is used for calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type and dynamically adjusting initial input parameters according to actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful.
Due to the adoption of the technical scheme, the invention has the following advantages:
1. aiming at the first surplus power problem, the alternating current energy consumption device is used for cutting off the electric field without depending on a generator tripping signal of a new energy electric field, so that the problem of failure in fault ride-through of a flexible direct current system caused by inaccurate switch displacement information corresponding to a new energy generator tripping is solved, and extra investment brought by a communication system is saved.
2. Aiming at the second surplus power problem, the alternating current energy consumption device automatically calculates and adjusts the input group number of the alternating current energy consumption device according to the electric quantity of the converter station where the alternating current energy consumption device is located, and the problem that the power disturbance of a flexible direct current system and a receiving end alternating current power grid is large when the internet power of the flexible direct current system is large and the surplus power is small is solved.
Therefore, the invention can be widely applied to the field of flexible direct current transmission.
Drawings
FIG. 1 is a typical wiring schematic diagram of a new energy electric field island access flexible direct current system;
FIG. 2 is a schematic diagram of typical wiring of an alternating current energy consumption device of a sending end converter station in a new energy electric field island access flexible direct current system;
FIG. 3 is a flow chart of an AC energy consuming device control method for the first category of surplus power problem employed by the present invention;
FIG. 4 is a flow chart of an AC energy consuming device control method for the second type of surplus power problem employed by the present invention;
fig. 5 is a schematic structural diagram of a control system of an ac energy consuming device according to the present invention.
Detailed Description
The present invention is described in detail by way of specific embodiments in order to better understand the technical direction of the present invention for those skilled in the art. It should be understood, however, that the detailed description is provided for a better understanding of the invention only and that they should not be taken as limiting the invention. In describing the present invention, it is to be understood that the terminology used is for the purpose of description only and is not intended to be indicative or implied of relative importance.
The invention provides a control method of an alternating current energy consumption device for a flexible direct current system, which judges the type of surplus power problems by monitoring signals and parameters of a converter station where the alternating current energy consumption device is located, and selects a corresponding switching method of the alternating current energy consumption device according to different types of surplus power problems. Specifically, the method comprises the following steps:
s1, monitoring a positive blocking signal, a negative blocking signal, a positive direct-current port voltage and a negative direct-current port voltage of a new energy electric field island access converter station in real time, and judging the type of surplus power problem according to a monitoring result;
and S2, calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type, and dynamically adjusting initial input parameters according to actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful.
Further, in the step S1, the method for determining the surplus power problem type includes:
if positive blocking signal or negative blocking signal B of converter station i ij If the power is suddenly changed from 0 to 1, the surplus power problem of the first type is judged, wherein j =1,2;1 represents a positive electrode, and 2 represents a negative electrode;
if in the time interval Deltat d At any time, the voltage of the positive electrode actual measurement direct current port of the converter station i or the voltage U of the negative electrode actual measurement direct current port ij Is greater than the input threshold voltage U of the AC energy consumption device in Judging the power surplus problem as a second type, wherein j =1,2;1 represents a positive electrode, and 2 represents a negative electrode.
Further, the step S2 specifically includes the following steps:
s2.1, if the problem is the first surplus power, calculating a first initial input group number of the alternating current energy consumption device according to the initial surplus power and rated active power consumed by a single group of alternating current energy consumption devices, and dynamically adjusting the first initial input group number according to actual measurement direct current port voltage and actual measurement active power of a sound pole of the converter station until the fault ride-through of a direct current system is successful;
s2.2, if the problem is the second type of surplus power, calculating a second initial input group number of the alternating current energy consumption device according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption device and the overvoltage electrode on-line power before the fault, and dynamically adjusting the second initial input group number according to the actually measured direct current port voltage of the overvoltage electrode of the converter station until the direct current system fault ride-through is successful.
Further, as shown in fig. 3, the method for calculating and dynamically adjusting the first initial number of groups of the ac energy consuming devices in step S2.1 includes the following steps:
s2.1.1, according to the initial active power P of the positive pole and the negative pole of the converter station i before the fault occurs 0ij Rated active power P of positive electrode and negative electrode of converter station i Nij Positive and negative blocking signals B of converter station i ij Calculating to obtain the initial surplus power delta P i0 . The calculation formula is as follows:
Figure BDA0003423287040000061
wherein the content of the first and second substances,
Figure BDA0003423287040000062
for positive or negative polarity closure of converter station iLock signal B ij And (4) taking out the negation.
S2.1.2, according to the initial surplus power delta P i0 Rated active power P consumed by single-group alternating current energy consumption device of converter station i cNi And calculating to obtain the initial input group number N of the alternating current energy consumption device i0 . The calculation formula is as follows:
Figure BDA0003423287040000063
wherein "is a rounded-up symbol.
S2.1.3, after the alternating current energy consumption device is put into or quit operation execution, dynamically adjusting the first initial input group number of the alternating current energy consumption device according to the actually measured direct current port voltage and the actually measured active power of the sound pole of the converter station until the fault ride-through of the flexible direct current system is successful.
Specifically, the method comprises the following steps:
after the alternating current energy consumption device is put into or quit the operation execution,
firstly, judging whether the voltage and the active power of the measured direct current port of the sound pole of the converter station meet the conditions of each preset alternating current energy consumption device or not: if the condition of casting a single group of alternating current energy consumption devices is met, delta t is arranged at intervals c The number of the input groups of the alternating current energy consumption devices is increased by 1; if the condition of withdrawing the single group of the alternating current energy consumption devices is met, the interval delta t is set c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group; otherwise, keeping the current state;
then, whether the current time reaches t is judged 0 +Δt 1 At the moment, if the current situation does not reach, returning to the previous step to continuously judge the conditions of the preset alternating current energy consumption devices; if the moment is reached, putting the alternating current energy consumption devices of the converter station i into the group number for zero clearing, and clearing the positive pole or negative pole locking signal, namely B i1 =0 or B i2 =0, wherein t 0 Is the initial input time of the 1 st group of AC energy consumption devices, delta t 1 The longest allowable investment period is used for exchanging energy consumption devices.
Wherein, the conditions of the single group of alternating current energy consumption devices are as follows: at time interval Deltat c At any time in the period, the voltage of the actually measured direct current port of the healthy pole of the converter station i is larger than the difference between the input threshold voltage of the alternating current energy consumption device and the deviation of the direct current voltage, or the actually measured active power of the healthy pole of the converter station i exceeds the allowable overload power. The calculation formula is as follows:
Figure BDA0003423287040000064
or
Figure BDA0003423287040000065
Δt＝Δt c (3)
The conditions for withdrawing the single-group alternating current energy consumption device are as follows: at time interval Deltat c At any time in the period, the voltage of an actually measured direct current port of the healthy pole of the converter station i is lower than the highest steady-state direct current voltage, and the online power of the healthy pole of the converter station i after the single group of alternating current energy consumption devices are estimated to be smaller than the rated active power of the healthy pole of the converter station i. The calculation formula is as follows:
Figure BDA0003423287040000071
and is
Figure BDA0003423287040000072
Δt＝Δt c (4)
Wherein, U ij Actually measuring the voltage of a direct current port for the anode or the cathode of a converter station i; u shape in Inputting a threshold voltage for the AC energy consuming device; delta U is a direct current voltage deviation; p ij The measured active power of the positive electrode or the negative electrode of the converter station i is obtained, and k is a reliability coefficient; u shape dmax The steady state maximum DC voltage; p cmaxi And the maximum active power consumed by the single group of alternating current energy consumption devices of the converter station i.
Further, as shown in fig. 4, the method for calculating and dynamically adjusting the second initial number of groups of the ac energy consuming devices in step S2.2 includes the following steps:
s2.2.1, according to the actually measured DC port voltage U of the overvoltage electrode of the converter station i ij From steady state maximum DC voltage U dmax To ac energy consuming devicesInput threshold voltage U in Time period Δ t of ij The number n of positive or negative single bridge arm sub-modules corresponding to overvoltage electrodes in the operation current station ij And the capacitance C of the individual sub-module capacitors 0ij Calculating the current surplus power delta P of the overvoltage electrode of the converter station i ij . The calculation formula is as follows:
Figure BDA0003423287040000073
wherein N is c Is the number of active stations in the flexible dc system.
S2.2.2, according to the initial active power of the positive electrode or the negative electrode of the convertor station i before the fault occurs and the overvoltage signal O of the positive electrode or the negative electrode of the convertor station i ij Rated active power P consumed by single-group alternating current energy consumption device cNi And calculating the input group number N of the alternating current energy consumption devices matched with the overvoltage grid power before the fault ijmax . The calculation formula is as follows:
Figure BDA0003423287040000074
s2.2.3, according to the current surplus power delta P of the overvoltage electrode of the converter station i ij Rated active power P consumed by single-group alternating current energy consumption device cNi And the input group number N of the alternating current energy consumption devices matched with the overvoltage grid power before the fault ijmax Calculating to obtain a second initial input group number N of the alternating current energy consumption device ij0 . The calculation formula is as follows:
Figure BDA0003423287040000075
and S2.2.4, dynamically adjusting the number of groups of the AC energy consumption devices according to the actually measured DC port voltage of the overvoltage electrode of the converter station after the AC energy consumption devices are put into or quit operation execution.
The method specifically comprises the following steps:
s3.4.1, after the AC energy consumption device is put into or quits operation execution, judging whether the actually measured DC port voltage of the overvoltage electrode at the current moment meets the conditions of each preset AC energy consumption device:
if the condition of over-throwing the AC energy consumption device is met, the number of groups thrown by the AC energy consumption device is increased by N ijmax -N ij Making the total input number reach N ijmax In which N is ij The current input group number of the i pole j alternating current energy consumption devices of the converter station is set;
if the conditions for casting a single group of alternating current energy consumption devices are met, delta t is set every time interval c The number of the input groups of the alternating current energy consumption devices is increased by 1 group;
if the condition of the single group of the alternating current energy consumption devices is met, delta t is set every time interval c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group;
if the conditions of exiting all the alternating current energy consumption devices are met, clearing the overvoltage signals of the positive electrode or the negative electrode of the converter station to zero, namely O i1 =0 or O i2 =0, and the number of groups of the AC energy consumption devices is reset;
otherwise, keeping the number of the input groups unchanged.
Wherein, the over-throw AC energy consumption device conditions are as follows: at time interval Deltat c At any time, the voltage of the actually measured direct current port of the overvoltage electrode of the converter station i is larger than the high voltage limit value U of the flexible direct current system lim . The calculation formula is as follows:
O ij U ij ＞U lim Δt＝Δt c (8)
the conditions of the single-group alternating current energy consumption device are as follows: at a time interval Δ t c At any time in the converter station, when the voltage of the measured direct current port U of the overvoltage electrode of the converter station i is over ij Are all larger than the input threshold voltage U of the alternating current energy consumption device in And the dc voltage deviation Δ U. The calculation formula is as follows:
O ij U ij ＜U in -ΔU Δt＝Δt c (9)
the conditions for withdrawing the single-group alternating current energy consumption device are as follows: at a time interval Δ t d At any time in the converter station, when the voltage U of the measured direct current port of the overvoltage electrode of the converter station i is over ij Are all below the sum of the steady state maximum dc voltage and the dc voltage deviation. The calculation formula is as follows:
O ij U ij ＜U dmax +ΔU Δt＝Δt c (10)
the conditions for withdrawing all the alternating current energy consumption devices are as follows: at a time interval Δ t d At any time, the actually measured DC port voltage of the overvoltage electrode of the converter station i is smaller than the exit threshold voltage U of the AC energy consumption device out . The calculation formula is as follows:
O ij U ij ＜U out Δt＝Δt d (11)
and S2.2.5, if the voltage of the actually measured direct current port of the overvoltage electrode of the converter station i rises again, making the overvoltage signal of the anode or the overvoltage signal of the cathode of the converter station i be 1, and returning to the step S1 until the fault ride-through of the flexible direct current system is successful.
Examples
In this embodiment, a flexible dc system connected to an island of a new energy electric field shown in fig. 1 is taken as an example for explanation. The converter station 1 and the converter station 2 are sending end converter stations; the converter station 1 is connected with 12 new energy electric fields, and the converter station 2 is connected with 8 new energy electric fields. The converter station 3 is connected to an alternating current power grid and is a direct current voltage regulation converter station, and the converter station 4 is connected to the alternating current power grid and is a receiving end converter station. The rated direct current voltage of the flexible direct current system is +/-500 kV, and the rated power of the positive electrode and the negative electrode of the convertor station 1 and the convertor station 4 is P N11 ＝P N12 ＝P N41 ＝P N42 =1500MW, and the rated power of the anode and cathode of the converter station 2 and 3 is P N21 ＝P N22 ＝P N31 ＝P N32 =750MW. The converter station 1 and the converter station 2 are provided with a plurality of groups of alternating current energy consumption devices, and the rated active power and the maximum active power consumed by the single group of energy consumption devices are respectively P cNi ＝375MW，P cmaxi =433MW. The highest stable DC voltage of the flexible DC system is U dmax =535kV, the input and exit threshold voltages of the AC energy consumption device are U respectively in ＝575kV，U out =515kV, dc voltage deviation Δ U =10kV, high voltage limit U of flexible dc system lim =580kV, and the reliability coefficient is k =1.05. The number of the single bridge arm submodules of the positive pole and the negative pole of the converter stations 1 to 4 is n ij =264The capacitance value of the capacitor of each submodule of the converter station 1 and the converter station 4 is C 0ij =15mF (i =1 or 4,j =1 or 2), and the capacitance value of the individual submodule capacitors of converter station 2 and converter station 3 is C 0ij =8mF (i =2 or 3,j =1 or 2), period Δ t d =2ms, time period Δ t c =10ms. Before the fault occurs, each converter station operates according to rated power, namely, P is met 0ij ＝P Nij I =1,2,3,4, representing the respective converter station, j =1,2, where 1 represents the positive pole and 2 represents the negative pole. P is 0ij Is the initial active power, P, of the positive or negative pole of the converter station i before the fault occurs Nij Is the rated active power of the anode or cathode of the converter station i.
(1) The first surplus power problem control method embodiment:
at a certain moment, the positive electrode of the converter station 1 is suddenly locked, and the control method of the alternating current energy consumption device comprises the following steps:
s1, switching on a positive blocking signal B of a converter station 1 to a new energy electric field island 11 Negative blocking signal B 12 Positive pole DC port voltage U 11 And negative DC port voltage U 12 Real-time monitoring is carried out, and a positive blocking signal B of the converter station 1 is found 11 The power is suddenly changed from 0 to 1, so that the surplus power problem of the first type is judged;
s2, calculating the initial input group number of the alternating current energy consumption devices according to the initial surplus power and the rated active power consumed by the single group of alternating current energy consumption devices, and dynamically adjusting the input group number of the alternating current energy consumption devices according to the actually measured direct current port voltage and the actually measured active power of the negative electrode of the converter station 1 until the fault ride-through of the flexible direct current system is successful. The method specifically comprises the following steps:
s2.1, according to initial active power P of the positive pole and the negative pole of the convertor station 1 before the fault happens 011 ＝P 012 =1500MW, rated active power P of the positive and negative poles of the converter station 1 N11 ＝P N12 =1500MW, positive and negative blocking signals B of the converter station 1 11 ＝1、B 12 =0, and the initial surplus power delta P is calculated according to the formula (1) 10 ＝1500MW。
S2.2, according to initial fillingResidual power Δ P 10 Rated active power P consumed by single group of alternating current energy consumption devices of converter station 1 cN1 =375MW, calculate according to equation (2) and get the initial input group number N of the AC energy consumption device 10 ＝4。
And S2.3, after the AC energy consumption device is put into or quit operation execution, dynamically adjusting the input group number of the AC energy consumption device according to the actually measured DC port voltage and the actually measured active power of the negative electrode of the converter station 1 until the fault ride-through of the flexible DC system is successful. The method specifically comprises the following steps:
s2.3.1, after the AC energy consumption device is put into or quit operation execution, finding that the voltage of the actually measured DC port of the negative electrode of the converter station 1 is increased and meets the condition of putting a single group of AC energy consumption devices, entering step S2.3.2, then cutting off 4 new energy electric fields in turn, finding that the voltage of the actually measured DC port of the negative electrode of the converter station 1 and the actually measured active power sequentially meet the condition of quitting the single group of AC energy consumption devices, and entering step S2.3.3 for 5 times.
Wherein, the conditions of the single group of alternating current energy consumption devices are as follows: at any time within a time interval of 10ms, the actually measured dc port voltage of the negative electrode of the converter station 1 is greater than the difference between the input threshold voltage of the ac energy consumption device and the dc voltage deviation, that is, 565kV, or the actually measured active power of the negative electrode of the converter station 1 exceeds the allowable overload power of 1575MW.
The conditions for withdrawing the single-group alternating current energy consumption device are as follows: at any time within 10ms, the actually measured direct-current port voltage of the negative electrode of the converter station 1 is lower than the steady-state highest direct-current voltage 535kV, and the estimated internet power of the negative electrode of the converter station 1 after exiting the single set of alternating-current energy consumption device is smaller than the rated active power 1500MW of the negative electrode of the converter station 1.
S2.3.2, increasing the number of the input groups of the alternating current energy consumption devices by 1 group every 10 ms;
s2.3.3, the number of the groups of the alternating current energy consumption devices which are put into the system every 10ms is reduced by 1 group.
S2.3.4, judging that the current moment reaches (0 + 1.5) s, resetting the group number of the alternating current energy consumption devices of the converter station 1 and resetting the positive locking signal, namely B 11 And =0, wherein the time 0s is an initial input time of the 1 st group of ac energy consuming devices, and 1.5s is a maximum allowable input time period of the ac energy consuming devices.
Therefore, the control process of the alternating current energy consumption device is finished, and the fault ride-through of the flexible direct current system is successful.
(2) The second type surplus power problem control method embodiment:
at some point a single-phase permanent earth fault suddenly occurs in the ac grid to which the converter station 4 is connected. After the fault occurs, the surplus power causes the direct current voltage of the flexible direct current system to continuously rise. Taking an alternating current energy consumption device of the converter station 1 as an example, the alternating current energy consumption device control method adopting the invention comprises the following steps:
s1, switching on a positive blocking signal B of a converter station to a new energy electric field island 11 Negative blocking signal B 12 Positive pole DC port voltage U 11 And negative DC port voltage U 12 Real-time monitoring is carried out, and the voltages U of the positive pole direct current port and the negative pole direct current port of the converter station 1 at any time within a period of 2ms are found 11 The input voltage of the AC energy consumption device is greater than 575kV, so the second type surplus power problem is judged.
S3, enabling the anode overvoltage signal O of the converter station 1 11 =1 and negative overvoltage signal O 12 =1; and calculating the initial input group number of the alternating current energy consumption devices according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage pole networking power before the fault, and dynamically adjusting the group number of the input alternating current energy consumption devices according to the actually measured direct current port voltage of the overvoltage pole of the converter station until the fault ride-through of the flexible direct current system is successful. The method specifically comprises the following steps:
s3.1, actually measuring the direct current port voltage U according to the anode of the converter station 1 11 And the voltage U of the DC port actually measured by the cathode 12 The period of time from the development of the highest steady-state direct-current voltage 535kV to the input threshold voltage 575kV of the alternating-current energy consumption device is 19.5ms, and the number n of single bridge arm sub-modules of the anode or the cathode of the current station ij And the capacitance value C of the individual sub-module capacitors 0ij Calculating the current surplus power delta P of the overvoltage pole of the converter station 1 according to the formula (5) 11 ＝ΔP 12 ＝493MW。
S3.2, according to the initial active power P of the anode and the cathode of the converter station 1 before the fault occurs 011 ＝P 012 =1500MW, positive and negative overvoltage signals O of the converter station 1 11 ＝O 12 =1 rated active power P consumed by single group AC energy consumption device cN1 =375MW, and the input group number N of the alternating current energy consumption devices matched with the grid-connected power on the overvoltage electrode before the fault is calculated according to the formula (6) 11max ＝N 12max And (4) groups.
S3.3, according to the current surplus power delta P of the overvoltage electrode of the converter station 1 11 ＝ΔP 12 =493MW, rated active power 375MW consumed by single-group AC energy consumption device, and number N of input groups of AC energy consumption devices matched with overvoltage grid power before fault 11max ＝N 12ma ＝ x 4 groups, and calculating according to the formula (7) to obtain the initial input group number N of the alternating current energy consumption device 110 ＝N 120 Group = 2.
And S3.4, dynamically adjusting the number of groups of the AC energy consumption devices according to the actually measured DC port voltage of the overvoltage electrode of the converter station after the AC energy consumption devices are put into or quit operation execution. The method specifically comprises the following steps:
s3.4.1, after the alternating current energy consumption device is put into or quit operation and execution, firstly, actually measuring the voltage of a direct current port of the positive electrode and the negative electrode to be increased, meeting the condition of putting a single group of alternating current energy consumption device, and entering the step S3.4.3; and then, successfully clearing the fault of the alternating current power grid, enabling the condition of the single-group-returning alternating current energy consumption device to meet, and sequentially entering the step S3.4.4 for 3 times.
Wherein, the over-throw AC energy consumption device conditions are as follows: at any time within 10ms, the voltage of the actually measured direct current port of the overvoltage electrode of the converter station 1 is larger than the high voltage limit value 580kV of the flexible direct current system.
The conditions of the single-group alternating current energy consumption device are as follows: at any time during the time interval 10ms, when the converter station 1 exceeds the measured dc port voltage U of the voltage pole 1j Are all larger than the input threshold voltage U of the alternating current energy consumption device in And the difference between the dc voltage deviation au, i.e., 565kV.
The conditions of withdrawing the single-group alternating current energy consumption device are as follows: at any time within the time interval 10ms, when the converter station 1 exceeds the measured DC port voltage U of the voltage pole 1j Are all lower than the sum of the steady-state maximum direct voltage and the direct voltage deviation, namely 545kV.
The conditions for withdrawing all the alternating current energy consumption devices are as follows: at any time within a time interval of 2ms, the actually measured direct current port voltage of the overvoltage electrode of the converter station 1 is smaller than the exit threshold voltage 515kV of the alternating current energy consumption device.
S3.4.2, putting in the alternating current energy consumption device to enable the number of the input groups to reach N 11max =4 or N 12max =4 groups;
s3.4.3, increasing the number of the groups of the alternating current energy consumption devices every 10ms by 1 group;
s3.4.4, the number of the alternating current energy consumption device groups is reduced by 1 group every 10 ms;
s3.4.5, zero clearing the overvoltage signals of the positive electrode and the negative electrode of the convertor station, namely O 11 =0 or O 12 And =0, and the number of groups of the AC energy consumption devices is reset.
And S3.5, then, the voltage of the actually measured direct current port of the overvoltage electrode of the converter station 1 rises again, and the step S1 is returned until the fault ride-through of the flexible direct current system is successful.
As shown in fig. 5, based on the same inventive concept, the present invention further provides a control system of an ac energy consuming device for a flexible dc system, comprising:
the surplus power type judgment module is used for monitoring a positive blocking signal, a negative blocking signal, a positive direct-current port voltage and a negative direct-current port voltage of a new energy electric field island access converter station in real time and judging the type of surplus power problem according to a monitoring result;
and the alternating current energy consumption device input group number adjusting module is used for calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type, and dynamically adjusting the initial input group number according to the actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful.
Further, exchange the consumer and put into group number of adjusting module and include:
the first adjusting module is used for calculating the initial input group number of the alternating current energy consumption device according to the initial surplus power and the rated active power consumed by the single group of alternating current energy consumption devices, and dynamically adjusting the input group number of the alternating current energy consumption device according to the actual measurement direct current port voltage and the actual measurement active power of the sound and full pole of the converter station until the fault ride-through of the flexible direct current system is successful;
and the second adjusting module is used for setting the positive overvoltage signal or the negative overvoltage signal of the converter station i to be 1, calculating the initial input group number of the alternating current energy consumption devices according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage electrode internet power before the fault, and dynamically adjusting the group number of the input alternating current energy consumption devices according to the actually measured direct current port voltage of the overvoltage electrode of the converter station until the fault ride-through of the flexible direct current system is successful.
Further, the first adjustment module includes: the initial surplus power calculation module is used for calculating to obtain initial surplus power; the first initial input group number calculation module is used for calculating a first initial input group number of the alternating current energy consumption device according to the initial surplus power and rated active power consumed by the single group of alternating current energy consumption devices; and the first dynamic adjustment module is used for dynamically adjusting the input group number of the alternating current energy consumption device according to the actual measurement direct current port voltage and the actual measurement active power of the sound pole of the converter station after the alternating current energy consumption device is put into or quit the operation execution until the fault ride-through of the flexible direct current system is successful.
Further, the second adjustment module includes: the current surplus power calculation module is used for actually measuring the voltage U of the direct current port according to the positive pole or the negative pole of the converter station i ij From steady state maximum DC voltage U dmax Developing to the input threshold voltage U of the AC energy consumption device in Time period Δ t of j Calculating the current surplus power Δ P j (ii) a A second initial input group number calculation module for calculating the current surplus power delta P j And rated active power P consumed by single group of alternating current energy consumption devices cNi Obtaining a second initial input group number of the alternating current energy consumption devices which are input into the positive electrode or the negative electrode; and the second dynamic adjustment module is used for dynamically adjusting the number of groups of the AC energy consumption devices according to the actually measured DC port voltage of the overvoltage electrode of the convertor station after the AC energy consumption devices are put into or quit operation execution until the fault ride-through of the flexible DC system is successful.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims. The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application should be defined by the claims.

Claims (7)

1. A control method of an alternating current energy consumption device for a flexible direct current system is characterized by comprising the following steps:
monitoring a positive locking signal, a negative locking signal, a positive direct current port voltage and a negative direct current port voltage of a new energy electric field island access converter station in real time, and judging the type of surplus power problem according to a monitoring result;
calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type, and dynamically adjusting the initial input group number according to actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful;
the method for calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type and dynamically adjusting the initial input group number according to the actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful comprises the following steps:
if the type is the first surplus power problem, calculating a first initial input group number of the alternating current energy consumption device according to the initial surplus power and rated active power consumed by a single group of alternating current energy consumption devices, and dynamically adjusting the first initial input group number according to actual measurement direct current port voltage and actual measurement active power of a healthy pole and a sound pole of the convertor station until the fault ride-through of the flexible direct current system is successful;
if the type is the second surplus power problem, calculating a second initial input group number of the alternating current energy consumption device according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage pole internet power before the fault, and dynamically adjusting the second initial input group number according to the actually measured direct current port voltage of the overvoltage pole of the converter station until the fault ride-through of the flexible direct current system is successful;
the method for dynamically adjusting the first initial input group number according to the actually measured direct current port voltage and the actually measured active power of the sound pole of the converter station comprises the following steps:
after the alternating current energy consumption device is put into or taken out of operation,
first, the converter station is judgediWhether the actual measurement direct current port voltage and the actual measurement active power of sound and perfect utmost point satisfy each and predetermine and exchange power consumption device condition: if the conditions of casting a single group of alternating current energy consumption devices are met, delta is set at intervalst c The number of the input groups of the alternating current energy consumption devices is increased by 1; if the condition of the single group of the alternating current energy consumption devices is met, delta is set every time intervalt c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group; otherwise, keeping the current state;
then, whether the current time arrives is judgedt 0 +Dt 1 Time: if not, repeating the previous step; if the time is reached, the converter station is arrangediThe input group number of the alternating current energy consumption device is cleared, and the anode or cathode locking signal is cleared, wherein,t 0 is the initial input time of the 1 st group of AC energy consumption devices, Dt 1 The longest allowable input time interval of the alternating current energy consumption device is set;
the conditions of the single-group-casting alternating current energy consumption device are as follows: at a time interval deltat c At any time in the converter station
Figure 982830DEST_PATH_IMAGE002
The voltage of the actual measurement direct current port of the sound pole is larger than the difference between the input threshold voltage of the alternating current energy consumption device and the deviation of the direct current voltage, or the converter stationiThe actual measurement active power of the sound pole exceeds the allowable overload power;
the conditions for withdrawing the single-group alternating current energy consumption device are as follows: at a time interval deltat c At any time in the converter station
Figure 260490DEST_PATH_IMAGE002
The voltage of the actual measurement direct current port of the sound pole is lower than the highest steady-state direct current voltage, and the converter station is estimated after the single group of alternating current energy consumption devices are withdrawniThe power of the network is lower than that of the convertor stationiHealthy pole rated active power.
2. The method as claimed in claim 1, wherein the method comprises the steps of: the method for judging the surplus power problem type according to the monitoring result comprises the following steps:
if a converter stationiPositive or negative blocking signal ofB ij If the power is suddenly changed from 0 to 1, judging the power is a first surplus power problem;
if in the time interval deltat d At any time in the converter stationiPositive pole measured DC port voltage or negative pole measured DC port voltageU ij Is greater than the input threshold voltage of the AC energy consumption deviceU in Judging the power surplus problem to be the second type, wherein j =1,2;1 represents a positive electrode, and 2 represents a negative electrode.
3. The method as claimed in claim 1, wherein the method comprises the steps of: in the first surplus power problem, the method for calculating the first initial input group number of the alternating current energy consumption device according to the initial surplus power and the rated active power consumed by the single group of alternating current energy consumption devices comprises the following steps:
according to the converter station before the fault occursiInitial active power of positive and negative electrodesP 0ij Converter stationiRated active power of positive and negative electrodesP Nij Converter stationiPositive and negative blocking signal ofB ij Calculating to obtain the initial surplus power deltaP i0 ；
According to initial surplus power deltaP i0 And a converter stationiRated active power consumed by single-group alternating current energy consumption deviceP cNi Calculating to obtain a first initial input group number N of the alternating current energy consumption device i0 。
4. The method for controlling the ac energy consumption device of the flexible dc system according to claim 1, wherein: the method for calculating the second initial input group number of the alternating current energy consumption device according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage power before the fault comprises the following steps:
according to converter stationiActual measurement direct current port voltage U of overvoltage electrode ij From steady state maximum DC voltageU dmax Developing to the input threshold voltage U of the AC energy consumption device in Time period delta oft ij The number of positive pole or negative pole single bridge arm sub-modules corresponding to overvoltage poles in the operation current stationn ij And the capacitance of the individual sub-module capacitorsC 0ij Calculating the converter stationiThe current surplus power Delta of the overvoltage electrodeP ij ；
According to the converter station before the fault occursiInitial active power of positive or negative pole, converter stationiPositive or negative overvoltage signalO ij Rated active power consumed by single-group alternating current energy consumption deviceP cNi And calculating to obtain the input group number of the alternating current energy consumption devices matched with the overvoltage grid power before the faultN ijmax ；
According to converter stationiThe current surplus power Delta of the overvoltage electrodeP ij Rated active power consumed by single-group alternating current energy consumption deviceP cNi And the number of groups of alternating current energy consumption devices matched with the overvoltage grid power before the faultN ijmax Calculating to obtain the second initial input group number of the AC energy consumption deviceN ij0 。
5. The method for controlling the ac energy consumption device of the flexible dc system according to claim 1, wherein: the method for dynamically adjusting the second initial input group number according to the actually measured direct current port voltage of the overvoltage electrode of the converter station comprises the following steps:
after the AC energy consumption device is put into or quit the operation execution, whether the actually measured DC port voltage of the overvoltage electrode at the current moment meets the conditions of each AC energy consumption device is judged:
if the condition of over-throwing the AC energy dissipation device is met, the number of groups of the AC energy dissipation device is increasedN ijmax -N ij Making the total input number reachN ijmax (ii) a WhereinN ij To converter stationsiPole(s)jExchanging the current input group number of the energy consumption devices;
if the conditions of casting a single group of alternating current energy consumption devices are met, delta is set at intervalst c The number of the input groups of the alternating current energy consumption devices is increased by 1;
if the condition of the single group of the alternating current energy consumption devices is met, delta is set every time intervalt c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group;
if the conditions of exiting all the alternating current energy consumption devices are met, clearing the overvoltage signals of the positive electrode or the negative electrode of the converter station, namelyO i1 =0 orO i2 =0, and the number of groups of the AC energy consumption devices is reset;
otherwise, keeping the number of the input groups unchanged.
6. The method as claimed in claim 5, wherein the method comprises the following steps: the over-throw alternating current energy consumption device conditions are as follows: in a time period deltat c At any time in the converter stationiThe voltage of the actual measurement direct current port of the overvoltage electrode is larger than the high voltage limit value of the direct current systemU lim ；
The conditions of the single-group alternating current energy consumption device are as follows: at a time interval deltat c At any time in the converter station
Figure 509069DEST_PATH_IMAGE002
Actual measurement direct current port voltage of overvoltage electrodeU ij Are all larger than the input threshold voltage of the alternating current energy consumption device
Figure 232174DEST_PATH_IMAGE004
And a DC voltage deviation DeltaUThe difference between the two; the conditions of withdrawing the single-group alternating current energy consumption device are as follows: at a time interval deltat c At any time in the converter stationiMeasured DC port voltage of overvoltage electrodeU ij Are all lower than the sum of the steady-state maximum direct-current voltage and the direct-current voltage deviation;
the conditions for withdrawing all the alternating current energy consumption devices are as follows: at a time interval deltat d At any time in the converter stationiThe voltage of the actual measurement direct current port of the overvoltage electrode is smaller than the exit threshold voltage of the alternating current energy consumption deviceU out 。
7. An alternating current energy consumption device control system for a flexible direct current system is characterized by comprising:
the surplus power type judgment module is used for monitoring a positive blocking signal, a negative blocking signal, a positive direct-current port voltage and a negative direct-current port voltage of a new energy electric field island access converter station in real time and judging the type of surplus power problem according to a monitoring result;
the module for adjusting the input group number of the alternating current energy consumption device is used for calculating the initial input group number of the alternating current energy consumption device according to the determined surplus power problem type and dynamically adjusting the initial input group number according to actual operation data of the converter station until the fault ride-through of the flexible direct current system is successful, and comprises the following steps:
if the type is the first surplus power problem, calculating a first initial input group number of the alternating current energy consumption device according to the initial surplus power and rated active power consumed by a single group of alternating current energy consumption devices, and dynamically adjusting the first initial input group number according to actual measurement direct current port voltage and actual measurement active power of a healthy pole and a sound pole of the convertor station until the fault ride-through of the flexible direct current system is successful;
if the type is the second surplus power problem, calculating a second initial input group number of the alternating current energy consumption device according to the current surplus power, the rated active power consumed by the single group of alternating current energy consumption devices and the overvoltage pole internet power before the fault, and dynamically adjusting the second initial input group number according to the actually measured direct current port voltage of the overvoltage pole of the converter station until the fault ride-through of the flexible direct current system is successful;
the method for dynamically adjusting the first initial input group number according to the actually measured direct current port voltage and the actually measured active power of the sound pole of the converter station comprises the following steps:
after the alternating current energy consumption device is put into or quit the operation execution,
first, a converter station is judgediWhether the actual measurement direct current port voltage and the actual measurement active power of sound utmost point satisfy each preset alternating current energy consumption device condition: if the conditions of casting a single group of alternating current energy consumption devices are met, delta is set at intervalst c The number of the input groups of the alternating current energy consumption devices is increased by 1; if the condition of returning the single set of the alternating current energy consumption devices is met, delta is set at intervalst c The number of the input groups of the alternating current energy consumption devices is reduced by 1 group; otherwise, keeping the current state;
then, whether the current time arrives is judgedt 0 +Dt 1 Time: if not, repeating the previous step; if the time is reached, the converter station is arrangediThe input group number of the alternating current energy consumption device is cleared, and the anode or cathode locking signal is cleared, wherein,t 0 is the initial input time of the 1 st group of AC energy consumption devices, Dt 1 The longest allowable input time interval of the alternating current energy consumption device is set;
the conditions of the single-group-casting alternating current energy consumption device are as follows: at a time interval deltat c At any time in the converter station
Figure 515388DEST_PATH_IMAGE002
The voltage of the actual measurement direct current port of the sound pole is larger than the difference between the input threshold voltage of the alternating current energy consumption device and the deviation of the direct current voltage, or the converter stationiThe measured active power of the healthy pole exceeds the allowable overload power;
the conditions of the single group withdrawing alternating current energy consumption device are as follows: at a time interval deltat c At any time in the converter station
Figure 931326DEST_PATH_IMAGE002
The voltage of the actual measurement direct current port of the sound pole is lower than the highest steady-state direct current voltage, and the converter station is estimated after the single group of alternating current energy consumption devices are withdrawniHealthy pole network access power is less than that of converter stationiThe rated active power of the pole is sound.
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