CN115514019A - Large-load test control method and system for carrying out flexible direct current delivery on new energy - Google Patents

Large-load test control method and system for carrying out flexible direct current delivery on new energy Download PDF

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Publication number
CN115514019A
CN115514019A CN202211253004.1A CN202211253004A CN115514019A CN 115514019 A CN115514019 A CN 115514019A CN 202211253004 A CN202211253004 A CN 202211253004A CN 115514019 A CN115514019 A CN 115514019A
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China
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end station
sending
receiving end
station
voltage
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CN202211253004.1A
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CN115514019B (en
Inventor
梅念
王光达
薛振宇
吴延坤
于慧芳
陈钊
佟宇梁
王海猷
李铁臣
邹格
王娜
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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
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
    • G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
    • G01R19/16538—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
    • G01R19/16547—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies voltage or current in AC supplies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • 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
    • H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
    • H02J3/48—Controlling the sharing of the in-phase component
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • 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]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The invention relates to a large load test control method and a system for carrying out flexible direct current delivery on new energy, which comprises the following steps: setting a connection mode and a steady-state control mode of a receiving end station and a sending end station in the first delivery system and the second delivery system, and charging the receiving end station and the sending end station of the two delivery systems, so that the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems is kept at a rated value level; unlocking a receiving end station and a sending end station in the first sending system and the second sending system respectively, and increasing the direct current port voltage of the receiving end station in the two sending systems and the alternating current bus voltage of the sending end station in the first sending system to a target value; and respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the first outgoing system or the second outgoing system reaches the rated power of the receiving end station. The invention can be widely applied to the field of flexible direct current transmission.

Description

Large-load test control method and system for carrying out flexible direct current delivery on new energy
Technical Field
The invention relates to the field of flexible direct current transmission, in particular to a large-load test control method and system for new energy through flexible direct current delivery.
Background
Compared with the traditional power transmission mode, the flexible direct current technology has the characteristics of realizing new energy power generation island grid connection, no commutation failure and the like, has obvious advantages in the aspects of large-scale new energy collection and transmission, and has wide application prospect.
In order to comprehensively verify the equipment capability in the flexible direct current engineering, a large load test is usually required to be carried out on the flexible direct current engineering before the flexible direct current engineering is put into operation formally. However, the new energy electric field and the flexible direct current engineering are often constructed in different phases, and the random fluctuation of the power of the new energy electric field on the internet is large, so that the requirements of the large load test of the flexible direct current engineering on the power and time of the internet are difficult to meet.
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 a large load test in which new energy is delivered via flexible direct current, which can effectively solve the problems that the new energy electric field and the flexible direct current engineering are not constructed in the same period, the random fluctuation of the power of the new energy electric field on the internet is large, and the requirements of the large load test of the flexible direct current engineering on the power and time on the internet are difficult to meet.
In order to realize the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a large load test control method for new energy through flexible direct current delivery, which comprises the following steps:
setting a connection mode and a steady-state control mode of a receiving end station and a sending end station in the first delivery system and the second delivery system, and charging the receiving end station and the sending end station of the two delivery systems to keep the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems at a rated value level;
unlocking a receiving end station and a sending end station in the first delivery system and the second delivery system respectively, and increasing the direct current port voltage of the receiving end station and the alternating current bus voltage of the sending end station in the first delivery system to a target value;
and respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the first outgoing system or the second outgoing system reaches the rated power of the receiving end station.
Further, the method for setting the connection mode and the steady-state control mode of the receiving end station and the sending end station in the first delivery system and the second delivery system and charging the receiving end station and the sending end station of the two delivery systems so that the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems is kept at a rated value level comprises the following steps:
the switches of the receiving end station and the sending end station in the first delivery system and the second delivery system are operated, so that the direct current sides of the receiving end station and the sending end station in the two delivery systems are in a pole connection state, and the alternating current sides are disconnected with the alternating current bus;
setting steady state control modes of a receiving end station and a transmitting end station of a first outgoing system and a second outgoing system, so that an active power circulation mode is presented between the first outgoing system and the second outgoing system;
and sequentially charging the receiving station and the sending station of the first outgoing system and the second outgoing system, so that the average working voltage of all sub-modules in the receiving station and the sending station in the two outgoing systems is kept at a rated value level.
Further, the method for operating the switches of the receiving end station and the sending end station in the first delivery system and the second delivery system to enable the direct current sides of the receiving end station and the sending end station in the two delivery systems to be in a pole connection state and the alternating current sides to be disconnected from the alternating current bus includes:
the method comprises the steps that alternating current and direct current switches of receiving end stations of a first delivery system and a second delivery system are automatically detected and operated in sequence, receiving end alternating current buses accessed by the two receiving end stations are enabled to be combined to run, the receiving end alternating current buses are communicated with a receiving end alternating current power grid, and receiving end station alternating current incoming line breakers in the first delivery system and the second delivery system are in an open state;
and automatically detecting and operating the sending end AC/DC switches of the first sending system and the second sending system in sequence to enable sending end AC buses accessed by the two sending end stations to operate in a combined mode, wherein the sending end AC buses are disconnected with the new energy electric field, and meanwhile, the sending end AC incoming line breakers of the first sending system and the second sending system are in a closing state and an opening state respectively.
Further, the method for sequentially charging the receiving end station and the sending end station of the first delivery system and the second delivery system so that the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems is kept at a rated value level comprises the following steps:
closing an alternating current incoming line breaker of a receiving end station in a first delivery system, and carrying out uncontrolled charging, controllable charging and dynamic voltage-sharing control on the receiving end station and a transmitting end station of the first delivery system through a receiving end alternating current power grid to finally keep the average working voltage of all submodules in the receiving end station and the transmitting end station in the first delivery system at a rated value level;
the receiving end station and the sending end station in the second outgoing system are charged by the same method.
Further, the method for unlocking the receiving end station and the sending end station in the first delivery system and the second delivery system respectively, and increasing the dc port voltage of the receiving end station and the ac bus voltage of the sending end station in the first delivery system to the target value includes:
when an unlocking instruction of the sending-out system is received, the receiving end stations of the first sending-out system and the second sending-out system are sequentially unlocked, and the voltage of the direct current ports of the two receiving end stations is promoted to a target value of the voltage of the direct current ports;
and unlocking the sending terminal station in the first sending system, lifting the voltage of the alternating-current bus of the sending terminal station to an alternating-current voltage target value, closing an alternating-current incoming line breaker of the sending terminal station in the second sending system, and unlocking the sending terminal station in the second sending system.
Further, the method for sequentially unlocking the receiving end stations of the first and second external transmission systems and boosting the dc port voltages of the two receiving end stations to the dc port voltage target value includes:
setting instruction values of a fixed direct-current voltage controller and a fixed reactive power controller of a receiving end station of a first delivery system, and then unlocking the receiving end station;
when the voltage measured value of the direct current port of the receiving end station of the first delivery system meets the preset direct current voltage condition, setting the instruction value of the fixed direct current voltage controller of the receiving end station to rise to the voltage target value of the direct current port according to the preset slope, so that the voltage measured value of the direct current port of the receiving end station rises;
when the voltage measured value and the reactive power measured value of the direct current port of the receiving end station of the first delivery system meet a preset direct current voltage lifting completion condition, judging that the voltage of the direct current port of the receiving end station of the first delivery system is lifted to a direct current port voltage target value;
and unlocking the receiving end station of the second external transmission system by adopting the same method, and boosting the voltage of the direct current port of the receiving end station to the target value of the voltage of the direct current port.
Further, the method for unlocking a sending end station in a first outgoing system, raising the voltage of an alternating current bus of the sending end station to an alternating current voltage target value, closing an alternating current incoming line breaker of the sending end station of a second outgoing system, and then unlocking the sending end station in the second outgoing system comprises the following steps:
setting a fixed alternating voltage controller instruction value of a first sending end station of a sending system to rise according to a first preset slope, setting a fixed frequency controller instruction value of the sending end station, and unlocking the sending end station;
when the command value of the fixed alternating voltage controller of the first sending-out system sending end station rises to a preset alternating voltage threshold value, keeping the command value unchanged;
when the actual AC bus voltage measurement value of the first delivery system delivery end station meets the preset AC bus voltage condition, setting the command value of the fixed AC voltage controller of the delivery end station to rise to the target AC bus voltage value according to a second preset slope, so that the actual AC bus voltage measurement value of the delivery end station rises;
when the measured value of the alternating-current bus voltage of the first delivery system delivery end station meets a preset alternating-current voltage lifting completion condition, judging that the alternating-current bus voltage of the delivery end station is lifted to a target value of the alternating-current bus voltage;
an AC incoming line breaker for closing the sending station of the second external transmission system, and a fixed active power controller instruction value P for setting the sending station 2Br =0, constant reactive power controller command value Q 2Br =0, and then unlock the sending end station.
Further, the method for respectively increasing the power of the forward dc system and the power of the reverse dc system until the measured value of the active power of the transmitting end station or the receiving end station in the outbound system reaches the rated power thereof includes:
the command value of the fixed active power controller of the sending end station of the second sending system is increased in an oblique manner until the actual active power measured value of the receiving end station of the first sending system reaches the rated power, and the required time for running a forward large-load test is kept;
and after the command value of the fixed active power controller of the transmitting end station of the second external transmission system is reduced to zero in a sloping way, the command value is reversely sloped and lifted until the active power measured value of the receiving end station of the second external transmission system reaches the rated power of the receiving end station, and the time required by the reverse heavy load test is kept.
Further, the method for increasing the command value of the active power controller at the sending end station of the second sending system in a diagonal manner until the measured value of the active power of the receiving end station of the first sending system reaches the rated power thereof includes:
setting the oblique lifting of the instruction value of the fixed active power controller of the sending end station of the second external transmission system until the instruction value of the fixed active power controller of the sending end station rises to a preset forward active power threshold value, and keeping the instruction value;
when the real measured value of the active power of the sending end station of the second external transmission system meets the preset positive active power condition, the command value of the fixed active power controller of the sending end station is updated to be in step ascending in a segmented mode until the real measured value of the active power of the receiving end station of the first external transmission system meets the preset positive active power ascending completion condition, the active power command value of the sending end station of the second external transmission system is recorded and kept at the moment, and meanwhile, the reactive power command value is kept to be zero.
Further, the method for decreasing the command value of the fixed active power controller of the transmitting end station of the second external transmission system to zero and then increasing the reverse slope until the measured value of the active power of the receiving end station of the second external transmission system reaches the rated power thereof includes:
setting a reverse oblique line lifting after an instruction value of a sending end station fixed active power controller of a second external transmission system is reduced to zero until the sending end station fixed active power controller is raised to a preset reverse active power threshold value, and keeping the instruction value;
when the actual measured value of the active power of the sending end station of the second external transmission system meets the preset reverse active power condition, updating the instruction value of the fixed active power controller of the sending end station into segmented step rise until the actual measured value of the active power of the receiving end station of the second external transmission system meets the reverse active power lifting completion condition, and recording and keeping the active power instruction value of the sending end station of the second external transmission system at the moment; while keeping the reactive power command at zero.
In a second aspect, the present invention provides a large load test control system for new energy sent out by flexible direct current, including:
the test preparation unit is used for setting a connection mode and a steady-state control mode of a receiving end station and a sending end station in the first delivery system and the second delivery system, and charging the receiving end station and the sending end station of the two delivery systems so that the average working voltage of all the sub-modules is kept at a rated value level;
the unlocking control unit is used for respectively unlocking the receiving end station and the sending end station of the first delivery system and the second delivery system and promoting the direct current port voltage of the receiving end station in the two delivery systems and the alternating current bus voltage of the sending end station in the first delivery system to a target value;
the large load test control unit is used for respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the first outgoing system or the second outgoing system reaches the rated power of the receiving end station;
and the acquisition unit is used for acquiring the related measured values of the two delivery systems and sending the measured values to the test preparation unit, the unlocking control unit and the heavy load control unit.
Due to the adoption of the technical scheme, the invention has the following advantages:
1. the method for controlling the large load test of the flexible direct current engineering can effectively solve the problems that the new energy electric field and the flexible direct current engineering are often constructed in different periods, the random fluctuation of the power of the new energy electric field on the internet is high, and the requirements of the large load test of the flexible direct current engineering on the power and the time of the internet are difficult to meet.
2. The large-load test control method of the flexible direct current engineering has almost zero requirements on active power and reactive power of an alternating current power grid and small disturbance on the alternating current power grid.
3. The maximum active power of each converter station in the test process by adopting the large-load test control method of the flexible direct current engineering is the rated active power of the converter station, and no extra overload capacity requirement is provided for the converter station.
Based on the advantages, the invention can be widely applied to the flexible direct current delivery system with new energy access.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Like reference numerals refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a schematic diagram of a typical topology of a system for delivering new energy via flexible DC;
FIG. 2 is a frame diagram of a control method for a large load test in which new energy is delivered by flexible direct current according to an embodiment of the present invention;
FIG. 3 is a flow chart of a test preparation method provided by an embodiment of the present invention;
fig. 4 is a flowchart of boosting dc port voltage of a receiving end station in two outgoing systems according to an embodiment of the present invention;
fig. 5 is a flowchart for raising the ac bus voltage at the delivery end station in the delivery system 1 and unlocking the delivery end station in the delivery system 2 according to the embodiment of the present invention;
FIG. 6 is a flow chart of the heavy duty test control provided by an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a large-load test control system for delivering new energy through flexible direct current.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
In some embodiments of the present invention, a method for controlling a large load test in which new energy is delivered via flexible direct current is provided, the method comprising: firstly, carrying out test preparation, including setting steady-state control modes of a receiving end station and a transmitting end station in the two delivery systems, enabling the two delivery systems to present an active power circulation mode, and charging all sub-modules in the receiving end station and the transmitting end station in the two delivery systems to keep the average working voltage at a rated value level; then, the voltage of the direct current port of the receiving end station in the two outgoing systems and the voltage of the alternating current bus of the sending end station in the first outgoing system are increased to a target value; and finally, respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the outgoing system 1 or the outgoing system 2 reaches the rated power of the receiving end station. The large load test control method of the flexible direct current engineering can effectively solve the problems that the new energy electric field and the flexible direct current engineering are often out of phase in construction, the random fluctuation of the internet power of the new energy electric field is large, and the requirements of the large load test of the flexible direct current engineering on the internet power and the time are difficult to meet.
Correspondingly, in other embodiments of the present invention, a large load test control system for delivering new energy via flexible direct current is provided.
Example 1
In this embodiment, a typical topology of the new energy source sent out by the flexible direct current system shown in fig. 1 is taken as an example, and a large load test control method of the new energy source sent out by the flexible direct current system provided in this embodiment is described. The exemplary topology includes flexible direct current delivery systems (abbreviated delivery systems) 1 and 2. The outward conveying system 1 comprises a receiving end converter station (receiving end station for short) 1-A and a sending end converter station (sending end station for short) 1-B, the outward conveying system 2 comprises a receiving end station 2-A and a sending end station 2-B, the receiving end station 1-A and the receiving end station 2-A are both connected with an alternating current power grid, and the sending end station 1-B and the sending end station 2-B are both connected with a new energy electric field (such as a wind power field).
As shown in fig. 2, the method for controlling a large load test by delivering new energy via flexible direct current provided by this embodiment includes the following steps:
1) Preparation of the test: setting a connection mode and a steady-state control mode of a receiving end station and a sending end station in the delivery system 1 and the delivery system 2, and charging the receiving end station and the sending end station in the two delivery systems to keep the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems at a rated value level;
2) Unlocking control: respectively unlocking a receiving end station and a sending end station in the delivery system 1 and the delivery system 2, and increasing the direct current port voltage of the receiving end station in the delivery systems and the alternating current bus voltage of the sending end station in the delivery system 1 to a target value;
3) And (3) large load test control: and respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the outgoing system 1 or the outgoing system 2 reaches the rated power of the receiving end station.
Preferably, as shown in fig. 3, in the step 1), the method for preparing the test includes the following steps:
1.1 Switches of the receiving end station and the sending end station in the outgoing system 1 and the outgoing system 2 are operated, so that the direct current sides of the receiving end station and the sending end station in the outgoing systems are in a pole connection state, and the alternating current sides are disconnected with the alternating current bus;
1.2 Set up the steady state control mode of receiving end station and sending end station in the sending out system 1 and sending out system 2, make sending out system 1 and sending out and present the active power circulation mode between the systems 2;
1.3 To charge the receiving and sending stations in the outbound system 1 and the outbound system 2 in sequence so that the average operating voltage of all sub-modules in the receiving and sending stations in both the outbound systems is maintained at the rated level.
Preferably, in the step 1.1), the method for disconnecting the ac sides of the receiving end station and the sending end station in the two delivery systems from the ac bus includes:
and the receiving end AC bus connected into the two receiving end stations is closed to operate, the receiving end AC bus is communicated with a receiving end AC power grid, and meanwhile, the receiving end AC incoming line circuit breakers of the outward sending system 1 and the outward sending system 2 are both in an open state.
And the AC/DC switches of the sending end stations in the sending system 1 and the sending system 2 are automatically detected and operated in sequence, so that sending end AC buses accessed by the two sending end stations are combined to run, the sending end AC buses are disconnected with the new energy electric field, and meanwhile, the sending end station AC incoming line circuit breakers in the sending system 1 and the sending system 2 are in a closing state and an opening state respectively.
Preferably, in step 1.2), the method for setting the steady-state control modes of the receiving end station and the sending end station in the delivery system 1 and the delivery system 2 so that the active power circulation mode is present between the delivery system 1 and the delivery system 2 includes:
and setting receiving terminals in the outgoing system 1 and the outgoing system 2 to be in a constant direct-current voltage/constant reactive power control mode.
The sending terminals in the sending system 1 and the sending system 2 are respectively set to a constant alternating voltage/constant frequency control mode and a constant active power/constant reactive power control mode.
Preferably, in step 1.3), the method for sequentially charging the receiving station and the sending station in the outgoing system 1 and the outgoing system 2 so that the average operating voltage of all sub-modules in the receiving station and the sending station in the outgoing systems is kept at the rated value level comprises the following steps:
1.3.1 The alternating current incoming line circuit breaker of the receiving end station in the outgoing system 1 is closed, and the receiving end station and the sending end station in the outgoing system 1 are subjected to uncontrolled charging, controllable charging and dynamic voltage-sharing control through a receiving end alternating current power grid, so that the average working voltage of all sub-modules in the receiving end station and the sending end station in the outgoing system 1 is kept at a rated value level;
1.3.2 Charging the receiving and sending stations in the outbound system 2 in the same way as step 1.3.1).
In a preferred embodiment, in step 2), the method for unlocking the receiving end station and the sending end station in the outgoing system 1 and the outgoing system 2, respectively, and increasing the dc port voltage of the receiving end station in the outgoing system 1 and the ac bus voltage of the sending end station in the outgoing system 1 to the target values includes the following steps:
2.1 When an unlocking instruction of the sending-out system is received, the receiving end stations of the sending-out system 1 and the sending-out system 2 are sequentially unlocked, and the direct current port voltages of the two receiving end stations are promoted to a direct current port voltage target value;
2.2 Unlock the delivery station in the delivery system 1, raise the ac bus voltage of the delivery station to the ac voltage target value, close the ac incoming line breaker of the delivery station in the delivery system 2, and then unlock the delivery station in the delivery system 2.
Preferably, as shown in fig. 4, in step 2.1), the method for sequentially unlocking the receiving terminals of the outgoing system 1 and the outgoing system 2 and boosting the dc port voltages of the two receiving terminals to the dc port voltage target value includes:
2.1.1 Set the instruction values of the fixed direct-current voltage controller and the fixed reactive power controller of the receiving end station of the external transmission system 1, and then unlock the receiving end station;
2.1.2 When the measured value of the dc port voltage of the receiving end station of the delivery system 1 meets the preset dc voltage condition, setting the command value of the fixed dc voltage controller of the receiving end station to slowly increase to the target value of the dc port voltage according to the preset slope, so that the measured value of the dc port voltage of the receiving end station slowly increases;
2.1.3 When the measured value of the dc port voltage and the measured value of the reactive power of the receiving end station of the delivery system 1 satisfy the preset dc voltage boost completion condition, it is determined that the dc port voltage of the receiving end station of the delivery system 1 is boosted to the target dc port voltage value;
2.1.4 Adopting the same method as the steps 2.1.1) -2.1.3) to unlock the receiving end station of the outgoing system 2 and promote the voltage of the direct current port of the outgoing system to the target value of the voltage of the direct current port.
Preferably, in the step 2.1.1), the command value of the receiving end station-specific dc voltage controller of the delivery system 1 may be set to U 1Adr ＝0.85U do The command value of the fixed reactive power controller may be set to Q 1Ar =0, wherein U do Is the target value of the DC port voltage.
Preferably, in the step 2.1.2), the preset dc voltage condition is: Δ t sud At any time in the time interval, there is U 1Ad ∈[0.85×(1-ΔU * d )U do ，0.85×(1+ΔU * d )U do ]Wherein, U 1Ad Is the measured value of the voltage of the DC port of the receiving end station of the outgoing system 1, delta U * d For the per unit value of the permitted DC voltage deviation, Δ t sud A dc voltage stabilization timing threshold is preset.
Preferably, in the step 2.1.2), the command value of the constant dc voltage controller of the receiving end station of the delivery system 1 may be updated to U 1Adr ＝(0.85+0.02Δt)U do And delta t is the time interval between the current moment and the update moment of the instruction value, and delta t is less than or equal to 7.5s.
Preferably, in the step 2.1.3), the preset conditions for completing the dc voltage boost are:
Δt sud at any time in the time interval, the measured value U of the voltage of the DC port of the receiving end station of the sending-out system 1 is available 1Ad ∈[(1-ΔU * d )U do ，(1+ΔU * d )U do ]And the reactive power measured value Q of the receiving end station 1A ∈[Q 1Ar -ΔQ，Q 1Ar +ΔQ]Where Δ Q is the allowable reactive power deviation.
Preferably, in step 2.2), as shown in fig. 5, the method for unlocking a sending end station in the delivery system 1, raising the ac bus voltage of the sending end station to the ac voltage target value, closing the ac incoming line breaker of the sending end station in the delivery system 2, and then unlocking the sending end station in the delivery system 2 comprises:
2.2.1 Set up the constant ac voltage controller command value of the sending end station in the delivery system 1 to rise according to the first preset slope, set up the constant frequency controller command value of the sending end station at the same time, then unlock the sending end station;
2.2.2 When the command value of the constant ac voltage controller of the sending end station of the delivery system 1 rises to the preset ac voltage threshold, the command value is kept unchanged;
2.2.3 When the measured value of the ac bus voltage at the transmitting end station of the delivery system 1 meets the preset ac bus voltage condition, setting the command value of the fixed ac voltage controller of the transmitting end station to slowly rise to the target value of the ac bus voltage according to a second preset slope, so that the measured value of the ac bus voltage at the transmitting end station slowly rises;
2.2.4 When the measured value of the ac bus voltage at the transmitting end station of the delivery system 1 satisfies the preset ac voltage lifting completion condition, it is determined that the ac bus voltage at the transmitting end station is lifted to the ac bus voltage target value;
2.2.5 A.c. incoming line breaker for closing a transmission station of the outgoing system 2, a constant active power controller command value P for setting the transmission station 2Br =0, fixed reactive power controller command value Q 2Br =0, and then unlocks the sending end station.
Preferably, in the step 2.2.1), the constant ac voltage controller instruction value of the sending end station of the delivery system 1 may be set as:
U 1Bacr ＝0.1ΔtU Baco
wherein, U 1Bacr Sending a fixed alternating voltage controller instruction value of an end station for the outgoing system 1; u shape Baco Is the target value of the alternating voltage of the alternating current bus at the sending end.
The constant frequency controller command value may be set to:
f r ＝f Bn
wherein f is r Is a constant frequency controller command value; f. of Bn Is the nominal frequency.
Preferably, in the step 2.2.2), the preset ac voltage threshold may be set to 85% of the ac voltage target value of the sending-end ac bus.
Preferably, in the step 2.2.3), the preset ac bus voltage condition is:
Δt suac at any time in the time interval, U is available Bac ∈[0.85×(1-ΔU * Bac )U Baco ，0.85×(1+ΔU * Bac )U Baco ]Wherein, U Bac Measured value of AC bus voltage, Δ U, for the transmitting terminal * Bac Delta t is the per unit value of the allowable AC voltage deviation suac A predetermined ac voltage stabilization timing threshold is set.
Preferably, in the step 2.2.3), the constant ac voltage controller of the sending end station of the outgoing system 1The command value slowly rises to the target value of the AC bus voltage according to a second preset slope, which can be expressed as U 1Bacr ＝(0.85+0.02Δt)U Baco Wherein delta t is less than or equal to 7.5s.
Preferably, in the step 2.2.4), the preset ac voltage boost completion condition is:
Δt suac at any time in the time interval, the voltage measured value U of the alternating current bus of the sending terminal station Bac ∈[(1-ΔU * Bac )U Baco ，(1+ΔU * Bac )U Baco ]。
In a preferred embodiment, as shown in fig. 6, the method for boosting the forward dc system power and the reverse dc system power in step 3) respectively until the measured active power value of the receiving end station in the outgoing system reaches its rated power includes the following steps:
3.1 The instruction value of the fixed active power controller of the sending end station of the sending system 2 is increased in a sloping way until the actual measured value of the active power of the receiving end station of the sending system 1 reaches the rated power, and the required time for running the forward large load test is kept;
3.2 The command value of the fixed active power controller of the sending end station of the sending system 2 is inclined to zero and then reversely inclined to raise until the active power measured value of the receiving end station of the sending system 2 reaches the rated power, and the time required by the reverse large load test is kept running.
Preferably, in the step 3.1), the method for increasing the command value of the fixed active power controller of the sending end station of the sending system 2 in a ramp manner until the measured active power value of the receiving end station of the sending system 1 reaches the rated power thereof includes:
3.1.1 Set up the sending end station of the outgoing system 2 and decide the command value of the active power controller to promote diagonally, until the sending end station decides the active power controller command value to rise to the forward active power threshold value preserved, keep the command value;
3.1.2 When the real measured value of the active power of the transmitting station of the sending system 2 satisfies the predetermined forward active power condition, the transmitting station updates the command value of the fixed active power controller to be a step-up in segments until the real measured value of the active power of the receiving station of the sending system 1 is fullThe forward active power lifting finishing condition is preset, and the active power instruction value P of the sending terminal station of the outgoing system 2 at the moment is recorded and kept 2Bqr While keeping the reactive power command value at zero.
Preferably, in step 3.1.1), the fixed active power controller instruction value of the sending end station of the outgoing system 2 may be set as:
P 2Br ＝0.1P n Δt
wherein, P 2Br A fixed active power controller instruction value of a sending end station of the outgoing system 2; p n Is the monopole rated active power of the transmitting terminal station. That is, the fixed active power controller instruction value P of the transmitting end station of the outgoing system 2 is set 2Br At a slope of 0.1P n And rapidly rises.
More preferably, in the step 3.1.1), the preset forward active power threshold may be set to 85% of the monopole rated active power of the transmitting station, that is, 0.85P n 。
Preferably, in the step 3.1.2), the preset forward active power condition is: Δ t sp At any time in the time interval, P is available 2B ∈[0.85×(1-ΔP * )P n ，0.85×(1+ΔP * )P n ]Wherein, P 2B Is an actual measured value of the active power, delta P, of the transmitting end station of the outgoing system 2 * The allowable active power deviation per unit value; Δ t sp A threshold is timed for preset power stabilization;
the preset forward active power lifting finishing conditions are as follows: Δ t sp At any time in the time interval, P is available 1A ∈[(1-ΔP * )P n ，(1+ΔP * )P n ]Wherein, P 1A Is the measured value of the active power of the receiving end station of the outgoing system 1.
Preferably, in the step 3.1.2), the fixed active power controller command value of the transmitting end station of the outgoing system 2 increases in a stepwise manner, which may be denoted as P 2Br (nΔt s )＝P 2Br (nΔt s -Δt s )+0.01P n . Wherein, t 0 For the moment when the preset forward active power condition is satisfied, P 2Br (t 0 )＝0.85P n ，1≤n<15。
Preferably, in the step 3.2), the method for ramping down the command value of the fixed active power controller of the transmitting end station of the sending system 2 to zero and then ramping up the command value in the reverse direction until the measured active power value of the receiving end station of the sending system 2 reaches the rated power thereof includes:
3.2.1 Setting a reverse oblique line lifting after an instruction value of a sending end station fixed active power controller of the outgoing system 2 is reduced to zero until the sending end station fixed active power controller rises to a preset reverse active power threshold value, and keeping the instruction value;
3.2.2 When the actual measured value of the active power of the sending end station of the sending end system 2 satisfies the preset reverse active power condition, the command value of the fixed active power controller of the sending end station is updated to be stepped-up in segments until the actual measured value of the active power of the receiving end station of the sending end system 2 satisfies the reverse active power lifting completion condition, and the active power command value P 'of the sending end station of the sending end system 2 at the moment is recorded and maintained' 2Bqr (ii) a While keeping the reactive power command at zero.
Preferably, in step 3.2.1), the instruction value of the sending end station active power controller of the outgoing system 2 may be set as:
P 2Br ＝P 2Bqr -0.1P n Δt
more preferably, the preset reverse active power threshold is set as: p 2Br ＝-0.85P n 。
Preferably, in the step 3.2.2), the preset reverse active power condition is: Δ t sp At any time in the time interval, the active power measured value P of the sending end station of the sending system 2 is available 2B ∈[0.85×(-1+ΔP * )P n ，0.85×(-1-ΔP * )P n ]；
The preset reverse active power lifting completion condition is as follows: Δ t sp At any time in the time interval, there is an active power measured value P of the sending end station of the sending system 2 2B ∈[(-1+ΔP * )P n ，(-1-ΔP * )P n ]。
Preferably, in the step 3.2.2), the command value of the fixed active power controller of the transmitting end station of the outgoing system 2 is set to be a step-by-step rise,can be represented as P 2Br (nΔt s )＝P 2Br (nΔt s -Δt s )-0.01P n . Wherein, t 0 For the moment when the preset reverse active power condition is satisfied, P 2Br (t 0 )＝-0.85P n ，1≤n<15。
Example 2
Correspondingly, the embodiment provides a large-load test control system for carrying out flexible direct current delivery on new energy. The system provided by this embodiment can implement the large load test control method of flexible direct current delivery of new energy in embodiment 1, and the system can be implemented by software, hardware, or a combination of software and hardware. For example, the system may comprise integrated or separate functional modules or functional units to perform the corresponding steps in the methods of embodiment 1. Since the system of this embodiment is substantially similar to the method embodiment, the description process of this embodiment is relatively simple, and reference may be made to part of the description of embodiment 1 for relevant points.
As shown in fig. 7, the large load test control system for delivering new energy via flexible direct current provided in this embodiment includes:
the test preparation unit is used for setting the connection mode and the steady-state control mode of the receiving end station and the sending end station in the delivery system 1 and the delivery system 2 and charging the receiving end station and the sending end station of the two delivery systems so that the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems is kept at a rated value level;
the unlocking control unit is used for respectively unlocking the receiving end station and the sending end station of the delivery system 1 and the delivery system 2, and increasing the direct current port voltage of the receiving end station in the two delivery systems and the alternating current bus voltage of the sending end station in the delivery system 1 to a target value;
the large load test control unit is used for respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the measured value of the active power of the receiving end station in the outward sending system 1 or the outward sending system 2 reaches the rated power of the outward sending system;
the acquisition unit is used for acquiring relevant measured values of the outgoing system and sending the measured values to the test preparation unit, the unlocking control unit and the heavy load control unit, wherein the acquired relevant measured values comprise: the transmission system 1 and the transmission system 2 receive the dc port voltage measured value, the active power measured value, the reactive power measured value of the end station, the transmission system 1 transmit the ac bus voltage measured value, the transmission system 2 transmit the active power measured value of the end station.
Preferably, the test preparation unit comprises a switch operation module, a control mode setting module and a converter station charging module, wherein the switch operation module is used for operating switches of a receiving end station and a sending end station in the delivery system 1 and the delivery system 2, so that direct current sides of the receiving end station and the sending end station in the two delivery systems are in a pole connection state, and alternating current sides of the receiving end station and the sending end station are disconnected with an alternating current bus; the control mode setting module is used for setting steady-state control modes of a receiving end station and a sending end station in the delivery system 1 and the delivery system 2 so that an active power circulation mode is presented between the delivery system 1 and the delivery system 2; and the converter charging module is used for sequentially charging the receiving end station and the transmitting end station of the outgoing system 1 and the outgoing system 2, so that the average working voltage of all sub-modules in the receiving end station and the transmitting end station in the two outgoing systems is kept at a rated value level.
Preferably, the unlocking control unit comprises a receiving end station unlocking control module, a sending end station unlocking control module of the delivery system 1 and a sending end station unlocking control module of the delivery system 2, wherein the receiving end station unlocking control module is used for sequentially unlocking receiving end stations of the delivery system 1 and the delivery system 2 when receiving an unlocking instruction of the delivery system and promoting the direct current port voltage of the two receiving end stations to a direct current voltage target value; the delivery end station unlocking control module of the delivery system 1 is used for unlocking the delivery end station in the delivery system 1 and promoting the voltage of an alternating current bus of the delivery end station to an alternating current voltage target value; and the sending end station unlocking control module of the outgoing system 2 is used for closing an alternating current incoming line breaker of the sending end station in the outgoing system 2 and unlocking the sending end station in the outgoing system 2.
Preferably, the high-load test control unit comprises a positive direction high-load control module and a negative direction high-load control module, wherein the positive direction high-load control module is used for obliquely lifting the instruction value of the fixed active power controller of the sending end station of the outgoing system 2 until the actual measured value of the active power of the receiving end station of the outgoing system 1 reaches the rated power thereof, and keeping the time required for running the positive direction high-load test; the reverse direction heavy load control module is used for reducing the oblique line of the instruction value of the fixed active power controller of the sending end station of the sending system 2 to zero and then reversely increasing the oblique line until the real measured value of the active power of the receiving end station of the sending system 2 reaches the rated power thereof, and then the reverse direction heavy load test required time is kept running.
Example 3
The method of the present invention will be further described in detail by taking the flexible dc delivery system of the new energy shown in fig. 1 as an example.
The delivery system 1 comprises a receiving end station 1-A and a sending end station 1-B, the delivery system 2 comprises a receiving end station 2-A and a sending end station 2-B, the receiving end station 1-A and the receiving end station 2-A are both connected with an alternating current power grid, and the sending end station 1-B and the sending end station 2-B are both connected with a new energy electric field (such as a wind power field). The rated power of the receiving end station 1-A, the receiving end station 2-A, the sending end station 1-B and the sending end station 2-B meets P N1A ＝P N2A ＝P N1B ＝P N2B =1500MW. DC port voltage target value U do =500kV, allowable DC voltage deviation per unit value delta U * d =0.01, preset dc voltage stabilization timing threshold Δ t sud =300ms; target value U of alternating current voltage of sending end alternating current bus Baco =230kV, rated frequency f Bn =50Hz, allowable AC voltage deviation per unit value Δ U * Bac =0.01, preset ac voltage stabilization timing threshold Δ t suac =300ms; allowable active power deviation per unit value delta P * =0.01, allowable reactive power deviation Δ Q =1Mvar, preset power stabilization timing threshold Δ t sp ＝300ms。
The invention discloses a large load test control method of new energy through flexible direct current delivery engineering, which comprises the following steps:
1) Preparation of a test: setting the connection mode and the control mode of the receiving end station 1-A, the receiving end station 2-A, the sending end station 1-B and the sending end station 2-B, and charging the receiving end station and the sending end station in the two delivery systems to keep the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems at a rated value level;
2) Unlocking control: respectively unlocking a receiving end station 1-A, a receiving end station 2-A, a sending end station 1-B and a sending end station 2-B, and boosting the direct current port voltage of the receiving end station 1-A and the receiving end station 2-A and the alternating current bus voltage of the sending end station 1-B to a target value;
3) And (3) large load control: and respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the measured value of the active power of the receiving end station in the outgoing system reaches the rated power of the receiving end station.
Preferably, in the step 1), the method for preparing the test comprises the following steps:
1.1 Switches of the receiving end station 1-A, the receiving end station 2-A, the sending end station 1-B and the sending end station 2-B are operated, so that direct current sides of the receiving end station and the sending end station in the two delivery systems are in a pole connection state, and alternating current sides of the receiving end station and the sending end station are disconnected with an alternating current bus;
1.2 Set up receiving end station 1-A, receiving end station 2-A, sending end station 1-B and sending end station 2-B steady state control mode, make send out and present the active power circulation mode between system 1 and 2;
1.3 To sequentially charge the receiving station 1-a and the sending station 1-B, the receiving station 2-a and the sending station 2-B, so that the average operating voltage of all sub-modules in the receiving station and the sending station in the two delivery systems is maintained at a rated value level.
Preferably, in step 1.1), the method for disconnecting the ac sides of the receiving end station and the sending end station in the two outgoing systems from the ac bus includes: the method comprises the following steps that alternating current and direct current switches of a receiving end station 1-A and a receiving end station 2-A are automatically detected and operated in sequence, a switch B10 is closed to enable receiving end alternating current buses accessed by the two receiving end stations to be combined to run, a switch B6 and a switch B7 are closed to enable the receiving end alternating current buses to be communicated with a receiving end alternating current power grid, an alternating current incoming line breaker B8 of the receiving end station 1-A is disconnected, and an alternating current incoming line breaker B9 of a sending end station 2-A is disconnected;
the method comprises the steps that AC/DC switches of a sending end station 1-B and a sending end station 2-B are automatically detected and operated in sequence, a switch B5 is closed to enable sending end AC buses accessed by the two sending end stations to be combined to run, the switches B1 and B2 are opened to enable the sending end AC buses to be disconnected from a new energy electric field, an AC incoming line breaker B3 of the sending end station 1-B is closed, and an AC incoming line breaker B4 of the sending end station 2-B is opened;
preferably, in step 1.2), the method for setting the steady-state control modes of the receiving end station and the transmitting end station in the delivery system 1 and the delivery system 2 so that the active power circulation mode is presented between the delivery system 1 and the delivery system 2 includes:
and setting the receiving end station 1-A and the receiving end station 2-A to be in a constant direct-current voltage/constant reactive power control mode.
Setting a sending end station 1-B and a sending end station 2-B into a constant alternating voltage/constant frequency control mode and a constant active power/constant reactive power control mode respectively;
preferably, in step 1.3), the method for sequentially charging the receiving station and the sending station in the outgoing system 1 and the outgoing system 2 so that the average operating voltage of all sub-modules in the receiving station and the sending station in the outgoing systems is kept at the rated value level comprises the following steps:
1.3.1 Closing an alternating current incoming line breaker B8 of a receiving end station 1-A, and carrying out uncontrolled charging, controllable charging and dynamic voltage-sharing control on the receiving end station 1-A and a sending end station 1-B through a receiving end alternating current power grid to finally keep the average working voltage of all sub-modules in the receiving end station and the sending end station in an outgoing system 1 at a rated value level;
1.3.2 Charging the receiving station 2-a and the sending station 2-B in the same manner as in step 1.3.1).
In a preferred embodiment, the step 2) includes the steps of:
2.1 When an unlocking instruction of the outgoing system is received, the receiving end station 1-A and the receiving end station 2-A are sequentially unlocked, and the voltage of the direct current ports of the two receiving end stations is promoted to a target value of the voltage of the direct current ports;
2.2 Unlock the end station 1-B, raise the end station ac bus voltage to the ac voltage target value, close the ac incoming line breaker B4 of the end station 2-B, and then unlock the end station 2-B.
Preferably, in the step 2.1), the method for sequentially unlocking the receiving end station 1-a and the receiving end station 2-a and increasing the dc port voltages of the two receiving end stations to the dc port voltage target value includes:
2.1.1 Setting command values of a fixed direct-current voltage controller and a fixed reactive power controller of a receiving end station 1-A, and then unlocking the receiving end station;
2.1.2 When the measured value of the voltage of the direct current port of the receiving end station 1-A meets the preset direct current voltage condition, setting the instruction value of the fixed direct current voltage controller of the receiving end station to slowly rise to the target value of the voltage of the direct current port according to the preset slope, so that the measured value of the voltage of the direct current port of the receiving end station slowly rises;
2.1.3 When the measured value of the dc port voltage and the measured value of the reactive power of the receiving end station 1-a satisfy the preset dc voltage boost completion condition, it is determined that the dc port voltage of the receiving end station 1-a is boosted to the dc port voltage target value;
2.1.4 Adopting the same method as the steps 2.1.1) -2.1.3) to unlock the receiving end station 2-A and promote the voltage of the direct current port to the target value of the voltage of the direct current port.
Preferably, in the step 2.1.1), the command value of the dc voltage controller determined by the receiving end station 1-a may be set to U 1Adr =425kV, and the instruction value of the constant reactive power controller can be set to Q 1Ar ＝0Mvar。
Preferably, in the step 2.1.2), the preset dc voltage condition is: Δ t sud At any time in the period of =300ms, there is U 1Ad ∈[420.75，429.25]kV, wherein, U 1Ad The voltage of the DC port of the receiving terminal station 1-A is measured.
Preferably, in the step 2.1.2), the command value of the constant dc voltage controller of the receiving end station 1-a may be updated to U 1Adr =425+10 Δ t kV, wherein Δ t is a time period from the instruction value updating moment at the current moment, and Δ t is less than or equal to 7.5s.
Preferably, in the step 2.1.3), the preset conditions for completing the dc voltage boost are:
Δt sud at any time in a time period of =300ms, there is a measured value U of the dc port voltage of the receiving end station 1-a 1Ad ∈[495，505]kV, and the reactive power measured value Q of the receiving end station 1A ∈[-1，1]Mvar。
Preferably, in the step 2.2), the method for unlocking the sending end station 1-B, raising the ac bus voltage of the sending end station to the ac voltage target value, closing the ac incoming line breaker of the sending end station 2-B, and then unlocking the sending end station 2-B comprises:
2.2.1 Setting a constant alternating voltage controller instruction value of a transmitting end station 1-B to rise according to a first preset slope, setting a constant frequency controller instruction value of the transmitting end station, and then unlocking the transmitting end station;
2.2.2 When the command value of the constant alternating voltage controller of the sending end station 1-B rises to a preset alternating voltage threshold value, keeping the command value unchanged;
2.2.3 When the measured value of the ac bus voltage of the transmitting end station 1-B satisfies the preset ac bus voltage condition, setting the command value of the fixed ac voltage controller of the transmitting end station to slowly rise to the target value of the ac bus voltage according to a second preset slope, so that the measured value of the ac bus voltage of the transmitting end station slowly rises;
2.2.4 When the measured value of the ac bus voltage of the transmitting end station 1-B satisfies the preset ac voltage boost completion condition, determining that the ac bus voltage of the transmitting end station is boosted to the ac bus voltage target value;
2.2.5 Ac incoming line breaker for closing the transmission station 2-B, setting the fixed active power controller command value P of the transmission station 2Br =0, fixed reactive power controller command value Q 2Br =0, and then unlock the sending end station.
Preferably, in the step 2.2.1), the constant ac voltage controller command value of the end station 1-B may be set as:
U 1Bacr ＝23Δt kV
wherein, U 1Bacr Is a constant AC voltage controller command value for the transmitting station 1-B.
The constant frequency controller command value may be set to:
f r ＝50Hz
wherein, f r Is a constant frequency controller command value.
Preferably, in the step 2.2.2), the preset ac voltage threshold may be set to 85% of the ac voltage target value of the sending-end ac bus, that is, 195.5kV.
Preferably, in step 2.2.3), the preset ac bus voltage condition is:
Δt suac ＝300m s at any time in the time interval, U is available Bac ∈[193.545，197.455]kV, wherein, U Bac The measured value of the AC bus voltage of the sending terminal station is obtained; .
Preferably, in the step 2.2.3), the command value of the constant ac voltage controller of the end station 1-B slowly rises to the target ac bus voltage according to a second preset slope, which may be represented as U 1Bacr 4.6 multiplied by delta t kV, wherein delta t is less than or equal to 7.5s.
Preferably, in the step 2.2.4), the preset ac voltage boost completion condition is:
Δt suac at any time in the time interval, the voltage measured value U of the alternating current bus of the sending terminal station Bac ∈[227.7，232.3]kV。
In a preferred embodiment, in step 3), the method for boosting the forward dc system power and the reverse dc system power respectively until the measured active power value of the receiving end station in the outgoing system reaches its rated power includes the following steps:
3.1 The instruction value of the fixed active power controller of the sending end station 2-B is increased in a sloping way until the actual measured value of the active power of the receiving end station 1-A reaches the rated power thereof, and the required time for running the forward large load test is kept;
3.2 The command value of the fixed active power controller of the sending end station 2-B is inclined to zero and then reversely inclined to lift until the active power measured value of the receiving end station 2-A reaches the rated power, and the time required by the reverse large load test is kept running.
Preferably, in the step 3.1), the method for increasing the command value of the fixed active power controller of the transmitting end station 2-B in a ramp manner until the measured value of the active power of the receiving end station 1-a reaches the rated power thereof includes:
3.1.1 Setting the instruction value of the fixed active power controller of the sending end station 2-B to be inclined and lifted until the instruction value of the fixed active power controller of the sending end station is raised to a preset positive active power threshold value, and keeping the instruction value;
3.1.2 When the sending end station 2-B is activeWhen the measured power value meets the preset positive active power condition, the command value of the fixed active power controller of the sending end station is updated to be in step ascending in sections until the measured active power value of the receiving end station 1-A meets the preset positive active power lifting completion condition, and the command value P of the active power of the sending end station 2-B at the moment is recorded and kept 2Bqr While keeping the reactive power command value at zero.
Preferably, in the step 3.1.1), the fixed active power controller instruction value of the sending end station 2-B may be set as:
P 2Br ＝150×Δt MW
wherein, P 2Br A fixed active power controller instruction value of the sending terminal station 2-B; p n Is the monopole rated active power of the transmitting terminal station. That is, the fixed active power controller instruction value P of the transmitting end station 2-B is set 2Br At a slope of 0.1P n And rapidly rises.
More preferably, in the step 3.1.1) above, the preset forward active power threshold may be set to 85% of the monopole rated active power of the transmitting end station, i.e. 1275MW.
Preferably, in step 3.1.2), the preset forward active power condition is: Δ t sp At any time in the time interval, P is available 2B ∈[1262.25，1287.75]MW, wherein, P 2B Is the real measured value of the active power of the sending terminal station 2-B;
the preset forward active power lifting completion conditions are as follows: Δ t sp At any time in the time interval, P is available 1A ∈[1485，1515]MW, wherein, P 1A Is the measured value of the active power of the receiving terminal station 1-A; .
Preferably, in the step 3.1.2), the fixed active power controller command value of the sending end station 2-B is increased in a step-by-step manner, and may be represented as P 2Br (nΔt s )＝P 2Br (nΔt s -Δt s ) +15MW. Wherein, t 0 For the moment when the preset forward active power condition is met, P 2Br (t 0 )＝1275MW，1≤n<15。
Preferably, in the step 3.2), the method for ramping down the command value of the fixed active power controller of the transmitting station 2-B to zero and then ramping up the command value in the reverse direction until the measured active power value of the receiving station 2-a reaches the rated power thereof includes:
3.2.1 Setting a reverse oblique line lifting after an instruction value of a sending end station 2-B fixed active power controller is obliquely reduced to zero until the sending end station fixed active power controller is raised to a preset reverse active power threshold value, and keeping the instruction value;
3.2.2 When the active power measured value of the transmitting end station 2-B meets the preset reverse active power condition, the transmitting end station-specific active power controller instruction value is updated to be in segmented step rise until the active power measured value of the receiving end station 2-A meets the reverse active power lifting completion condition, and the active power instruction value P 'of the transmitting end station 2-B at the moment is recorded and maintained' 2Bqr (ii) a While keeping the reactive power command at zero.
Preferably, in step 3.2.1), the instruction value of the sending end station 2-B fixed active power controller may be set as:
P 2Br ＝P 2Bqr -150×Δt
more preferably, the preset reverse active power threshold is set as: p is 2Br ＝-1500MW。
Preferably, in the step 3.2.2), the preset reverse active power condition is: Δ t sp At any time in the time interval, the active power measured value P of the sending terminal station 2-B 2B ∈[-1262.25，-1287.75]MW；
The preset reverse active power lifting completion condition is as follows: Δ t sp At any time in the time interval, the active power measured value P of the sending terminal station 2-B 2B ∈[-1485，-1515]MW。
Preferably, in the step 3.2.2), the fixed active power controller command value of the sending end station 2-B is set to be a stepwise step rise, which may be denoted as P 2Br (nΔt s )＝P 2Br (nΔt s -Δt s ) -15MW. Wherein, t 0 For the moment when the preset reverse active power condition is satisfied, P 2Br (t 0 )＝-1275MW，1≤n<15。
The above embodiments are only used for illustrating the present invention, and the implementation steps and the like can be changed, and all equivalent changes and modifications based on the technical scheme of the present invention should not be excluded from the protection scope of the present invention.

Claims (11)

1. A large-load test control method for new energy through flexible direct current delivery is characterized by comprising the following steps:
setting a connection mode and a steady-state control mode of a receiving end station and a sending end station in the first delivery system and the second delivery system, and charging the receiving end station and the sending end station of the two delivery systems, so that the average working voltage of all sub-modules in the receiving end station and the sending end station in the two delivery systems is kept at a rated value level;
unlocking a receiving end station and a sending end station in the first delivery system and the second delivery system respectively, and increasing the direct current port voltage of the receiving end station and the alternating current bus voltage of the sending end station in the first delivery system to a target value;
and respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the first outgoing system or the second outgoing system reaches the rated power of the receiving end station.
2. The method for controlling the high-load test of the new energy through flexible direct current delivery according to claim 1, wherein the method for setting the connection mode and the steady-state control mode of the receiving end station and the sending end station in the first delivery system and the second delivery system and charging the receiving end station and the sending end station of the two delivery systems so that the average operating voltage of all the submodules in the receiving end station and the sending end station in the two delivery systems is kept at a rated value level comprises the following steps:
the switches of the receiving end station and the sending end station in the first delivery system and the second delivery system are operated, so that the direct current sides of the receiving end station and the sending end station in the two delivery systems are in a pole connection state, and the alternating current sides are disconnected with the alternating current bus;
setting steady state control modes of a receiving end station and a transmitting end station of a first sending system and a second sending system, so that an active power circulation mode is presented between the first sending system and the second sending system;
and sequentially charging the receiving station and the sending station of the first outgoing system and the second outgoing system, so that the average working voltage of all sub-modules in the receiving station and the sending station in the two outgoing systems is kept at a rated value level.
3. The method for controlling the high-load test of the new energy through flexible direct current delivery according to claim 2, wherein the method for operating the switches of the receiving end station and the sending end station in the first delivery system and the second delivery system so that the direct current sides of the receiving end station and the sending end station in the two delivery systems are in a polar connection state and the alternating current sides of the receiving end station and the sending end station are disconnected from the alternating current bus comprises the following steps:
the method comprises the following steps that alternating current and direct current switches of receiving end stations of a first delivery system and a second delivery system are sequentially and automatically detected and operated, so that receiving end alternating current buses accessed by the two receiving end stations are combined to run, the receiving end alternating current buses are communicated with a receiving end alternating current power grid, and meanwhile receiving end station alternating current incoming line circuit breakers in the first delivery system and the second delivery system are in an open brake state;
the method comprises the steps that alternating current and direct current switches of the sending end stations of the first sending system and the second sending system are automatically detected and operated in sequence, sending end alternating current buses accessed by the two sending end stations are enabled to be in bus-closing operation, the sending end alternating current buses are disconnected with a new energy electric field, and meanwhile sending end station alternating current incoming line circuit breakers in the first sending system and the second sending system are in switch-on and switch-off states respectively.
4. The method for controlling the high load test of the new energy through the flexible direct current delivery according to claim 3, wherein the method for sequentially charging the receiving station and the sending station of the first delivery system and the second delivery system so that the average working voltage of all the sub-modules in the receiving station and the sending station in the two delivery systems is kept at a rated value level comprises the following steps:
closing an alternating current incoming line breaker of a receiving end station in a first outgoing system, and carrying out uncontrolled charging, controllable charging and dynamic voltage-sharing control on the receiving end station and a transmitting end station of the first outgoing system through a receiving end alternating current power grid to finally keep the average working voltage of all sub-modules in the receiving end station and the transmitting end station in the first outgoing system at a rated value level;
the receiving end station and the sending end station in the second outgoing system are charged by the same method.
5. The method for controlling the high-load test of the new energy through the flexible direct current delivery according to claim 2, wherein the method for unlocking the receiving end station and the sending end station in the first delivery system and the second delivery system respectively and increasing the voltage of the direct current port of the receiving end station in the two delivery systems and the voltage of the alternating current bus of the sending end station in the first delivery system to the target value comprises the following steps:
when an unlocking instruction of the sending-out system is received, the receiving end stations of the first sending-out system and the second sending-out system are sequentially unlocked, and the voltage of the direct current ports of the two receiving end stations is promoted to a target value of the voltage of the direct current ports;
and unlocking the sending terminal station in the first sending system, lifting the voltage of the alternating-current bus of the sending terminal station to an alternating-current voltage target value, closing an alternating-current incoming line breaker of the sending terminal station in the second sending system, and unlocking the sending terminal station in the second sending system.
6. The method for controlling the high load test of the new energy through flexible direct current delivery according to claim 5, wherein the method for sequentially unlocking the receiving terminals of the first delivery system and the second delivery system and raising the direct current port voltages of the two receiving terminals to the direct current port voltage target value comprises the following steps:
setting instruction values of a fixed direct-current voltage controller and a fixed reactive power controller of a receiving end station of a first outgoing system, and then unlocking the receiving end station;
when the voltage measured value of the direct current port of the receiving end station of the first delivery system meets the preset direct current voltage condition, setting the instruction value of the fixed direct current voltage controller of the receiving end station to rise to the voltage target value of the direct current port according to the preset slope, so that the voltage measured value of the direct current port of the receiving end station rises;
when the voltage measured value and the reactive power measured value of the direct current port of the receiving end station of the first delivery system meet a preset direct current voltage lifting completion condition, judging that the voltage of the direct current port of the receiving end station of the first delivery system is lifted to a direct current port voltage target value;
and unlocking the receiving end station of the second external transmission system by adopting the same method, and boosting the voltage of the direct current port of the receiving end station to the target value of the voltage of the direct current port.
7. The method for controlling the new energy source to pass the heavy load test of the flexible direct current delivery according to claim 5, wherein the method for unlocking the sending end station in the first delivery system, raising the alternating current bus voltage of the sending end station to the alternating current voltage target value, closing the alternating current incoming line breaker of the sending end station in the second delivery system, and then unlocking the sending end station in the second delivery system comprises:
setting a fixed alternating-current voltage controller instruction value of a sending end station of a first delivery system to rise according to a first preset slope, setting a fixed frequency controller instruction value of the sending end station, and then unlocking the sending end station;
when the command value of the fixed alternating-current voltage controller of the first sending-out system sending end station rises to a preset alternating-current voltage threshold value, keeping the command value unchanged;
when the actual AC bus voltage measurement value of the first delivery system delivery end station meets the preset AC bus voltage condition, setting the command value of the fixed AC voltage controller of the delivery end station to rise to the target AC bus voltage value according to a second preset slope, so that the actual AC bus voltage measurement value of the delivery end station rises;
when the measured value of the alternating-current bus voltage of the first delivery system delivery end station meets a preset alternating-current voltage lifting completion condition, judging that the alternating-current bus voltage of the delivery end station is lifted to a target value of the alternating-current bus voltage;
an AC incoming line breaker for closing the sending station of the second external transmission system, and a fixed active power controller instruction value P for setting the sending station 2Br =0, fixed reactive power controller command value Q 2Br =0, and then unlocks the sending end station.
8. The method according to claim 5, wherein the method for controlling the new energy through the large load test of the flexible dc delivery comprises the steps of raising the power of the forward dc system and the power of the reverse dc system respectively until the measured value of the active power of the transmitting station or the receiving station in the delivery system reaches the rated power, and comprises:
the command value of the fixed active power controller of the sending end station of the second sending system is increased in a sloping way until the actual active power measured value of the receiving end station of the first sending system reaches the rated power thereof, and the required time for running a forward large load test is kept;
and after the command value of the fixed active power controller of the transmitting end station of the second external transmission system is reduced to zero in a sloping way, the command value is reversely sloped and lifted until the active power measured value of the receiving end station of the second external transmission system reaches the rated power of the receiving end station, and the time required by the reverse heavy load test is kept.
9. The method according to claim 8, wherein the method for controlling the new energy through the large load test of the flexible dc transport comprises the steps of increasing the command value of the active power controller determined by the transmitting station of the second transport system in a ramp manner until the measured active power value of the receiving station of the first transport system reaches the rated power thereof, and comprises:
setting the oblique lifting of the instruction value of the fixed active power controller of the sending end station of the second external transmission system until the instruction value of the fixed active power controller of the sending end station rises to a preset forward active power threshold value, and keeping the instruction value;
and when the actual active power measured value of the sending end station of the second external transmission system meets the preset positive active power condition, updating the instruction value of the fixed active power controller of the sending end station into sectional step rise until the actual active power measured value of the receiving end station of the first external transmission system meets the preset positive active power rise completion condition, recording and keeping the actual active power instruction value of the sending end station of the second external transmission system at the moment, and simultaneously keeping the reactive power instruction value to be zero.
10. The method for controlling a large load test of flexible dc delivery of new energy according to claim 8, wherein the method for ramping down the command value of the fixed active power controller of the transmitting end station of the second delivery system to zero and then ramping up the command value in a reverse direction until the measured active power value of the receiving end station of the second delivery system reaches its rated power comprises:
setting a reverse oblique line lifting after an instruction value of a sending end station fixed active power controller of a second external transmission system is reduced to zero until the sending end station fixed active power controller is raised to a preset reverse active power threshold value, and keeping the instruction value;
when the actual active power measured value of the sending end station of the second external transmission system meets the preset reverse active power condition, the command value of the fixed active power controller of the sending end station is updated to be in sectional step ascending until the actual active power measured value of the receiving end station of the second external transmission system meets the reverse active power lifting finishing condition, and the active power command value of the sending end station of the second external transmission system at the moment is recorded and kept; while keeping the reactive power command at zero.
11. A large load test control system for new energy through flexible direct current delivery is characterized by comprising:
the test preparation unit is used for setting the connection mode and the steady-state control mode of a receiving end station and a sending end station in the first delivery system and the second delivery system, and charging the receiving end station and the sending end station of the two delivery systems so that the average working voltage of all the submodules is kept at a rated value level;
the unlocking control unit is used for respectively unlocking the receiving end station and the sending end station of the first delivery system and the second delivery system and promoting the direct current port voltage of the receiving end station in the two delivery systems and the alternating current bus voltage of the sending end station in the first delivery system to a target value;
the large load test control unit is used for respectively increasing the power of the forward direct current system and the power of the reverse direct current system until the actual measured value of the active power of the receiving end station in the first outgoing system or the second outgoing system reaches the rated power of the receiving end station;
and the acquisition unit is used for acquiring the related measured values of the two delivery systems and sending the measured values to the test preparation unit, the unlocking control unit and the heavy load control unit.
CN202211253004.1A 2022-10-13 2022-10-13 Large-load test control method and system for new energy sent out by flexible direct current Active CN115514019B (en)

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