CN-117374927-B - Multi-terminal series-parallel ultrahigh voltage direct current engineering main loop parameter calculation method and system

CN117374927BCN 117374927 BCN117374927 BCN 117374927BCN-117374927-B

Abstract

The invention relates to a method and a system for calculating main loop parameters of an extra-high voltage direct current engineering with multiple ends, wherein the method comprises the steps of obtaining a multi-end direct current system network matrix related to valve group port voltages and direct current of each series-parallel converter station with different operation conditions through matrix transformation on the basis of a network equation of a traditional port direct current voltage and a direct current, solving the multi-end direct current system network matrix according to different control modes and combining a Newton-Lafson method by adopting an N-order matrix normalization method to obtain direct current parameters in the multiple control modes, and obtaining converter transformer tap positions through given triggering and turn-off angles based on the direct current parameters to calculate converter parameters. The main loop parameter calculation speed is high, and the accuracy of the calculation result is high.

Inventors

WANG LING
YIN JIAN
LI ZHICHUANG
HAO ZHIYUAN
XU YING
LI MING
SHEN XIAOLIN
ZHAO ZHENG
WU FANGJIE
XUE YINGLIN
DU SHANGAN
WANG YAOXUAN

Assignees

国网经济技术研究院有限公司

Dates

Publication Date: 20260508
Application Date: 20230927

Claims (9)

1. The method for calculating the parameters of the main loop of the extra-high voltage direct current engineering of the multi-terminal series-parallel connection is characterized by comprising the following steps of: Based on the network equation of the traditional port direct-current voltage and direct-current, obtaining a multi-terminal direct-current system network matrix related to the port voltage and the direct-current of the valve group of each series-parallel converter station under different operation conditions through matrix transformation; solving a network matrix of the multi-terminal direct current system according to different control modes and combining with a Newton Lafson method by adopting an N-order matrix normalization method to obtain direct current parameters under the multi-control mode; Based on the direct current parameters, calculating the position of a converter transformer tap through given triggering and turn-off angles, and calculating the parameters of the converter; The establishment of the network matrix of the multi-terminal direct current system is as follows: in the n-end direct current transmission system, an admittance matrix is listed by using a node voltage method, a network matrix suitable for the multi-end direct current transmission system under the operation condition is obtained through deduction, and the matrix is separated to obtain general equations (13) and (14) under the series-parallel structure: (13) (14) wherein U is dn 、U dn For each positive pole and negative pole converter valve group voltage, R en 、R en I d1H and I d1L respectively correspond to currents flowing through positive and negative pole series valve groups, when no series valve group exists in a network, I d1H and I d1L are both 0, n ranges from 1, I dnH 、I dnL respectively represents current vectors at outlets of the positive pole and the negative pole converter valve groups, and U d12 represents voltage of the series valve groups; Wherein a= ; The method for solving the network matrix of the multi-terminal direct current system comprises the steps of listing the network matrix according to a network structure, and solving direct current voltage and direct current by utilizing a Newton Lapherson method according to a control mode; calculating inverter parameters, comprising: At a rated level, determining the position of the converter tap through a given trigger angle and a given turn-off angle; For other power levels, the converter tap positions are adjusted so that parameters of each converter meet a first constraint and corresponding converter power parameters are calculated, wherein each parameter includes a firing angle and a shutdown angle, a tap limit, and a DC voltage limit.
2. The method for calculating the parameters of the extra-high voltage direct current engineering main loop of the multi-terminal hybrid according to claim 1, wherein the step of calculating the tap position of the converter by giving the trigger angle and the turn-off angle comprises the following steps: And judging P, Q whether a set second constraint condition is met or not by giving a trigger angle and a turn-off angle, if so, calculating the range of the ideal no-load direct current voltage U di0 of the converter according to the control mode of the direct current system on the basis of the direct current parameters of the multi-terminal direct current system, and determining the range of a tap, and if not, recalculating the direct current parameters.
3. The method for calculating the parameters of the main loop of the extra-high voltage direct current engineering with the multi-terminal series-parallel connection as claimed in claim 2, wherein the second constraint condition is: And ; If P, Q is not out of limit, then the first constraint condition is satisfied; the minimum power is delivered to the inverter, For maximum power transfer to the inverter, For minimum reactive power consumption of the converter station, Maximum reactive power consumption for the converter station.
4. The method for calculating the parameters of the main loop of the extra-high voltage direct current engineering with the multi-terminal series-parallel connection according to claim 1, wherein adjusting the tap position of the converter comprises the following steps: the tap is adjusted, and parameters are adjusted to meet the first constraint condition under the condition that the control mode and the instruction value of each converter are not changed; if the tap reaches the regulation limit specified by the first constraint, the control mode or the instruction value of some converter stations is changed, and if the first constraint is not met, the direct current parameter is recalculated.
5. The method for calculating the parameters of the main loop of the multi-terminal hybrid extra-high voltage direct current engineering according to claim 4, wherein the first constraint condition is as follows: Triggering and off angle of the converter station: 、 ; tap limiting: ; Direct current voltage limitation: 。
6. The method for calculating the main loop parameter of the multi-terminal hybrid extra-high voltage direct current engineering according to claim 4, wherein the step of recalculating the direct current parameter if the first constraint condition is not satisfied comprises the steps of: After the DC parameter is calculated, a new trigger angle is calculated based on the original ideal no-load voltage U di0Ri Angle of turn off ; When the trigger angle is If the ideal no-load DC voltage U di0 of the converter does not reach the minimum limit value, directly Calculating the ideal no-load DC voltage U di0 of the converter, if the ideal no-load DC voltage U di0 of the converter reaches the limit value, then And returning to the direct current parameter part again for calculation, and recalculating parameters of each converter.
7. A multi-terminal series-parallel extra-high voltage direct current engineering main loop parameter calculation system, which is used for realizing the multi-terminal series-parallel extra-high voltage direct current engineering main loop parameter calculation method according to any one of claims 1 to 6, and is characterized by comprising the following steps: the direct current network matrix acquisition module is used for obtaining a multi-terminal direct current system network matrix of the valve group port voltage and the direct current of each series-parallel converter station under different operation conditions through matrix transformation on the basis of a network equation of the direct current and the direct voltage of a traditional port; The direct current parameter calculation module adopts an N-order matrix normalization method, and solves a network matrix of the multi-terminal direct current system according to different control modes and by combining with a Newton Lafson method to obtain direct current parameters under the multi-control mode; the converter parameter calculation module is used for calculating the converter transformer tap position through given triggering and turn-off angles based on the direct current parameters and calculating the converter parameters.
8. A computer readable storage medium storing one or more programs, wherein the one or more programs comprise instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-6.
9. A computing device comprising one or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods of claims 1-6.

Description

Multi-terminal series-parallel ultrahigh voltage direct current engineering main loop parameter calculation method and system Technical Field The invention relates to the technical field of direct current transmission systems, in particular to a method and a system for calculating parameters of a main loop of an extra-high voltage direct current engineering of a multi-terminal hybrid. Background Compared with the traditional two-end direct current engineering, the cascade multi-end high-voltage direct current power transmission can more flexibly and economically transmit power, for example, the power is transmitted from a plurality of power supply bases through a direct current transmission technology, or a power supply or a load is branched in midway, or a certain power supply base supplies power to a plurality of load areas, and the mode can realize reasonable and optimal configuration of power resources. The multi-terminal parallel extra-high voltage direct current transmission main loop parameter calculation method has related research, the multi-terminal parallel connection is a connection mode that a plurality of converter stations are identical in voltage class and are mutually connected in parallel, but the research on multi-terminal main loop parameters of the parallel-serial structure of the multi-terminal parallel connection and the parallel connection is relatively less at home and abroad, and because the converter stations are connected in parallel and in series at the same time, the direct current voltage coupling and the direct current coupling are contained between the stations, and the calculation method is more complex. In the process of designing the direct-current transmission project, the calculation of the main loop parameters is the basis, the result of the main loop parameters is used as the input of the design of the direct-current filter of the direct-current transmission project, and the accuracy and the rapidity of the calculation are important. Disclosure of Invention Aiming at the problems, the invention aims to provide a multi-terminal hybrid extra-high voltage direct current engineering main loop parameter calculation method and system, wherein the main loop parameter calculation speed is high, and the calculation result accuracy is high. The technical scheme is that the method comprises the steps of obtaining a multi-terminal direct current system network matrix of each series-parallel converter station with different operation conditions, wherein the multi-terminal direct current system network matrix is related to valve group port voltage and direct current through matrix transformation on the basis of a network equation of traditional port direct current voltage and direct current, solving the multi-terminal direct current system network matrix according to different control modes and combining with a Newton Lafson method to obtain direct current parameters under the multi-control mode, and obtaining converter change tap positions through given triggering and turn-off angles based on the direct current parameters to calculate converter parameters. Further, calculating inverter parameters includes: At a rated level, determining the position of the converter tap through a given trigger angle and a given turn-off angle; For other power levels, the converter tap positions are adjusted so that parameters of each converter meet a first constraint and corresponding converter power parameters are calculated, wherein each parameter includes a firing angle and a shutdown angle, a tap limit, and a DC voltage limit. Further, determining the converter tap position by a given firing angle and shutdown angle includes: And judging P, Q whether a set second constraint condition is met or not by giving a trigger angle and a turn-off angle, if so, calculating the range of the ideal no-load direct current voltage U di0 of the converter according to the control mode of the direct current system on the basis of the direct current parameters of the multi-terminal direct current system, and determining the range of a tap, and if not, recalculating the direct current parameters. Further, the second constraint is P cmin≤P≤Pcmax and Q acmin≤Q≤Qacmax; If P, Q is not out of limit, then the first constraint is satisfied. Further, adjusting the converter tap position includes: the tap is adjusted, and parameters are adjusted to meet the first constraint condition under the condition that the control mode and the instruction value of each converter are not changed; if the tap reaches the regulation limit specified by the first constraint, the control mode or the instruction value of some converter stations is changed, and if the first constraint is not met, the direct current parameter is recalculated. Further, the first constraint is: The triggering and off angle of the converter station is alpha min≤α≤αmax、γmin≤γ≤γmax; Tap limit n Tcmin≤nT≤nTmax; DC voltage limitation U dmin≤Ud≤Udmax. Further, recalcu