A dynamic simulation system, high-speed communication architecture and control method based on UPFC

Abstract

The present application discloses a UPFC dynamic simulation system, a high-speed communication architecture and a control method. The UPFC dynamic simulation system of the present invention includes a UPFC physical entity system, a UPFC digital twin system, a high-speed communication architecture and an interconnection interface; the UPFC digital twin system includes a simulation model, a control system, a visualization interface and an application service module; the high-speed communication architecture includes a number of hosts and a communication network, the hosts are used to implement the converter process and its control in the UPFC physical entity system, and to implement the various functions of the UPFC digital twin system, and the communication network is used for communication between the hosts; the control method includes a STATCOM mode, a UPFC mode and a fault protection mode. The present invention can perform virtual mapping on the UPFC physical entity system, and provide higher network throughput capacity and effectively improve the data transmission speed, and can effectively meet the requirements of actual engineering for the operation, protection, etc. of the UPFC, and has advantages such as multiple functions, high communication efficiency and high intelligent level.

Description

Technical Field

[0001] The present invention belongs to the field of electrical engineering technology, and in particular relates to a dynamic model system based on UPFC, a high-speed communication architecture and a control method. Background Art

[0002] The Unified Power Flow Controller (UPFC) combines the series compensation technology with the Static Synchronous Compensator (STATCOM), which can realize the precise control of the power system flow, significantly improving the transmission capacity and the safe and stable operation level of the power grid. However, in daily operation and maintenance, it is found that the "black module" problem caused by optical module failure, uplink communication fiber failure, board failure and module power failure seriously affects the reliable operation of the system, and its complex inducement also greatly increases the difficulty and workload of operation and maintenance. Among them, single-channel uplink communication is one of the main sources of increasing the hidden dangers of "black module" failure. In addition, the main functions of the UPFC monitoring system in the current project are status information visualization, equipment-side system control protection and typical fault handling, etc., but the status monitoring of key parameters that cannot be obtained by sensors, or the potential fault assessment based on historical working conditions, etc. are all lacking. The intelligent and digital operation and maintenance capabilities of the UPFC monitoring system still need to be improved.

[0003] The existing technologies for UPFC simulation, control or protection are:

[0004] The patent with publication number CN111026078A proposes a hardware-in-the-loop test system for a hybrid UPFC control and protection algorithm, including: a simulation system, a switching device and a hybrid UPFC control and protection device, the simulation system is used to generate simulation operating parameters of UPFC according to the operating environment of UPFC; the switching device is used to receive the simulation operating parameters obtained by simulation of the simulation system, and send the simulation operating parameters to the hybrid UPFC control and protection device after protocol conversion; the hybrid UPFC control and protection device is used to receive the simulation operating parameters after protocol conversion, calculate the simulation operating parameters according to the hybrid UPFC control and protection algorithm, and generate a command signal; the switching device receives the command signal and sends it to the simulation system; the simulation system is used to execute the command signal, generate simulation operating data, and generate test results according to the simulation operating data.

[0005] The patent with the publication number CN108574282A proposes a power flow control method of UPFC in a microgrid based on nonlinear control, including the following steps: analyzing the power flow control mode of the microgrid; analyzing the working principle of UPFC; analyzing the power flow control characteristics of UPFC in the microgrid; establishing the nonlinear mathematical model and control objective of UPFC; adopting the series-side backstepping sliding mode control strategy to maintain the stability of the control system at the equilibrium point; adopting the parallel-side decoupling control strategy to compensate for the reactive power regulation ability of the series side; determining the example and its necessary characteristics, and using Matlab / Simulink software to conduct simulation analysis on the example. The method of the present invention lays a foundation for the design of the power flow controller; establishes the nonlinear mathematical model of UPFC; adopts the decoupling control strategy based on the reactive power control mode for the parallel-side controller; enhances the anti-interference ability against system nonlinearity and external disturbances, effectively realizes the control of the line power flow, determines the power regulation range, and realizes the balanced distribution of system power.

[0006] The patent with the publication number CN110768268A provides a method and system for adjusting the HVDC power control strategy considering the operation of UPFC. The method and system collect the historical data of the power grid, establish a time-domain simulation analysis model on the simulation software, and when a local disturbance occurs in the power grid, under the active power control strategy of the active power modulation model of the grid HVDC, determine whether there is power oscillation in the tie section monitored by the active power modulation model. When there is power oscillation, judge whether the power output branches sampled by the UPFC constant active power control model and the active power modulation model of the HVDC transmission section overlap. When there is overlap, remove the reference branch in the UPFC constant power control branch. When there is no overlap, prevent the occurrence of power oscillation by correcting the HVDC power modulation control parameters.

[0007] However, none of the above solutions can effectively combine the physical entity and the virtual space and explore the interconnection relationship, with few functions, limited communication performance, and low intelligence level. Summary of the Invention

[0008] In view of this, the present invention provides a dynamic simulation system, high-speed communication architecture and control method of UPFC, which realizes system construction through digital twin technology, is used to solve the problems of few functions, limited communication performance, low intelligence level, etc. of the existing UPFC monitoring system, provides important technical support for the construction of digital and intelligent power grid equipment, and has a wide application prospect.

[0009] To solve the above technical problems, the present invention adopts the following technical solutions:

[0010] The present invention provides a UPFC dynamic simulation system, which includes a UPFC physical entity system, a UPFC digital twin system, a high-speed communication architecture, and an interconnection interface. The UPFC physical entity system includes a sending-end AC source and a receiving-end AC source , an upper DC bus U dc +, a lower DC bus U dc -, a sending-end line impedance X S , a receiving-end line impedance X R , a shunt transformer T sh , a series transformer T se , a shunt-side converter, a series-side converter, a first circuit breaker QF1, a second circuit breaker QF2, a third circuit breaker QF3, a fourth circuit breaker QF4, a first disconnecting switch DS1, a second disconnecting switch DS2, a third disconnecting switch DS3, a fourth disconnecting switch DS4, a fifth disconnecting switch DS5, a sixth disconnecting switch DS6, a seventh disconnecting switch DS7, an eighth disconnecting switch DS8, a fuse FU, and a thyristor bypass switch TBS; and is characterized in that:

[0011] The UPFC digital twin system is used to simulate, control, and provide application services for the UPFC physical entity system. The UPFC digital twin system includes a simulation model, a control system, a visualization interface, and an application service module;

[0012] The interconnection interface is used to realize data information interaction between the UPFC physical entity system and the UPFC digital twin system;

[0013] The simulation model simulates each physical component in the UPFC circuit under the conditions of an electric field, a thermal field, and a stress field, and the simulation model is used for being called by the control system and the application service module; the control system is used for controlling the UPFC physical entity system and the simulation model in the UPFC digital twin system, and simultaneously obtaining actual operation data and simulation operation data; the visualization interface is used for monitoring and recording the sequence control process conditions of each converter, the real-time operation waveforms of the UPFC physical entity system and the UPFC digital twin system, and the system states of the UPFC physical entity system and the UPFC digital twin system;

[0014] The application service module is used for abnormal state diagnosis and analysis, fault location and early warning analysis, historical data replay, and health state assessment.

[0015] Preferably, the simulation model is divided into a basic model, an average model, and a dynamic model according to the time scale. The static parameters of each physical component are simulated by the basic model. The average model is the physical quantity of each physical component at a long time scale interval. The dynamic model additionally adds dynamic characteristics on the basis of the average model, including the on-off transient process of the switching tube.

[0016] Preferably, the high-speed communication architecture includes several hosts and a communication network. The hosts are used to implement the converter process and its control in the UPFC physical entity system and to implement the functions of the UPFC digital twin system. The communication network is used for communication between the hosts.

[0017] The hosts in the high-speed communication architecture include a shunt-side converter host, a series-side converter host, a protection service host, an intelligent auxiliary host, a first server, a second server, and an operable upper computer. The shunt-side converter host is used to implement the sequence control process and its control of the shunt-side converter. The series-side converter host is used to implement the sequence control process and its control of the series-side converter. The protection service host is used to implement converter protection, transformer protection, and AC line protection. The intelligent auxiliary host is used to provide all functions of the UPFC digital twin system. The first server and the second server cooperate to implement communication functions and provide services such as centralized computing, information publishing, and data management. The operable upper computer provides a friendly human-computer interaction interface.

[0018] Preferably, the communication network of the high-speed communication architecture uses a dual-LAN networking, including LAN1, the first LAN2, an RJ45 Ethernet interface, a second RJ45 Ethernet interface, a first Ethernet signal transformer, a second Ethernet signal transformer, a first MAC / PHY transceiver, a second MAC / PHY transceiver, and a CPU. One end of the first RJ45 Ethernet interface is connected to LAN1, and the other end is connected to one end of the first Ethernet transformer. The other end of the first Ethernet transformer is connected to one end of the first MAC / PHY transceiver. The other end of the first MAC / PHY transceiver is connected to the CPU. One end of the second RJ45 Ethernet interface is connected to LAN2, and the other end is connected to one end of the second Ethernet transformer 2. The other end of the second Ethernet transformer is connected to one end of the second MAC / PHY transceiver. The other end of the second MAC / PHY transceiver is connected to the CPU.

[0019] The second aspect of the present invention proposes a high-speed communication architecture using the dynamic simulation system described in the first aspect of the present invention.

[0020] The high-speed communication architecture includes several hosts and a communication network. The hosts are used to implement the converter process and its control in the UPFC physical entity system and to implement the functions of the UPFC digital twin system. The communication network is used for communication between the hosts.

[0021] Preferably, the communication network of the high-speed communication architecture adopts a dual-LAN networking, including LAN1, the first LAN2, RJ45 Ethernet interfaces, the second RJ45 Ethernet interface, the first Ethernet signal transformer, the second Ethernet signal transformer, the first MAC / PHY transceiver, the second MAC / PHY transceiver, and the CPU. One end of the first RJ45 Ethernet interface is connected to LAN1, and the other end is connected to one end of the first Ethernet transformer. The other end of the first Ethernet transformer is connected to one end of the first MAC / PHY transceiver. The other end of the first MAC / PHY transceiver is connected to the CPU. One end of the second RJ45 Ethernet interface is connected to LAN2, and the other end is connected to one end of the second Ethernet transformer 2. The other end of the second Ethernet transformer is connected to one end of the second MAC / PHY transceiver. The other end of the second MAC / PHY transceiver is connected to the CPU.

[0022] The second aspect of the present invention provides a control method for using the UPFC dynamic simulation system described in the first aspect of the present invention. When the system only needs rapid reactive power compensation, the series side does not work, and the shunt side operates in the STATCOM mode. When the system needs to control power flow, voltage distribution, and take into account dynamic reactive power compensation, the series side is connected and the shunt side operates in the UPFC mode. When a fault occurs in the system, operation fault protection is performed.

[0023] When in the STATCOM mode, the shunt side operates in grid-side AC voltage control. When in the UPFC mode, the shunt side operates in reactive power control. The series side operates under line active power control and line reactive power control, and the series side performs line fault restart control. Before the series side is connected, the series side executes smooth start control. The operation fault protection includes line protection, transformer protection, and UPFC body protection.

[0024] Preferably, the smooth start control is specifically as follows:

[0025] S1. Before starting, the states of each circuit breaker and disconnector are as follows: the first circuit breaker QF1 is open, the second circuit breaker QF2 is closed, the third circuit breaker QF3 is open, the fourth circuit breaker QF4 is closed, the first disconnector DS1 is open, the second disconnector DS2 is open, the third disconnector DS3 is open, the fourth disconnector DS4 is open, the fifth disconnector DS5 is open, the sixth disconnector DS6 is open, the seventh disconnector DS7 is open, and the eighth disconnector DS8 is open. Set the start parameters of the series-side converter according to the system requirements.

[0026] S2. Close the second disconnector DS2, the third disconnector DS3, the seventh disconnector DS7, the eighth disconnector DS8, the fifth disconnector DS5, the sixth disconnector DS6, and the fourth disconnector DS4 in sequence;

[0027] S3. Close the third circuit breaker QF3 to complete the charging of the primary winding of the series transformer T; se Disconnect the fourth circuit breaker QF4 to complete the connection between the secondary winding of the series transformer T and the series-side converter; se

[0028] S4. Close the first circuit breaker QF1. At the same time, the parallel-side converter and the series-side converter receive the start signal and start charging. At this time, the current loop of the series-side converter uses the circuit transmission current i 1 as the reference value to control the output current of the series-side converter i se to be close to the circuit transmission current i 1 converted to the secondary side. When the amplitude difference between the two is less than the set smooth access current threshold of the series side, it indicates that the charging is completed. Close the first disconnector DS1, then disconnect the second circuit breaker QF2. At the same time, the reference value of its current loop is converted to the output of the voltage loop of the series-side converter. At this time, the series-side converter is smoothly connected to the main circuit.

[0029] Preferably, setting the start parameters of the series-side converter according to system requirements includes the active power reference of the series-side converter , the reactive power reference of the series-side converter and the smooth access current threshold of the series side. The set values of both are the same as those in the rated operating condition.

[0030] Preferably, the line fault restart control is specifically as follows: When a fault occurs, determine whether the fault is a line fault or a device fault. When it is determined to be a line fault, close the thyristor bypass switch TBS, block the series-side converter, and isolate the series-side converter from the main circuit and withdraw it from operation;

[0031] After the reclosing setting time, the reclosing setting time is the time set from when the slave device senses the disconnection of the circuit breaker to when the device allows the issuance of a closing command; By detecting the line voltage, current, and switch position, determine whether the line is operating normally. If it is normal, open the thyristor bypass switch TBS and restart and put into operation the series-side converter.

[0032] Preferably, the reclosing setting time is set between 0.8 - 2.0 s.

[0033] Preferably, the line protection, transformer protection, and UPFC body protection for operation fault protection are specifically as follows: line protection includes overvoltage protection and circuit breaker protection; transformer protection includes transformer electrical quantity protection and transformer non-electrical quantity protection; UPFC body protection specifically includes parallel side actions and series side actions;

[0034] Parallel side actions: alarm, switch the control system, block the parallel side converter, trip the parallel transformer converter side switch, trip the parallel transformer grid side switch in case of failure;

[0035] Series side actions: alarm, switch the control system, block the series side converter, trigger the thyristor bypass switch TBS to conduct, close the series transformer line side bypass switch, close the series transformer converter side bypass switch;

[0036] Fault tripping of the series side from the parallel side: In case of a fault in the series side AC area, only the converter on the corresponding side is exited; in case of a fault in the series side converter area, the other sides are tripped.

[0037] The beneficial effects of the present invention compared with the prior art are as follows:

[0038] The present invention provides a UPFC dynamic simulation system, a high-speed communication architecture, and a control method. By establishing the connection between the UPFC physical entity and the virtual mapping space through digital twin technology, a reliable and efficient information communication network is established using a dual-LAN networking method, a control strategy matching the engineering practice is proposed to meet different on-site requirements, and a variety of application services supporting digital twin are provided, thus effectively solving the deficiencies in functions and communications of the original UPFC monitoring system and providing an important reference for realizing the digital and intelligent upgrade of UPFC equipment operation and maintenance. Description of the Drawings

[0039] Figure 1 is a schematic structural diagram of a UPFC dynamic simulation system disclosed in an embodiment of the present application;

[0040] Figure 2 is a schematic diagram of the dual-LAN communication network connection disclosed in an embodiment of the present application;

[0041] Figure 3 Schematic diagram of the parallel side converter control of the control system disclosed in an embodiment of the present application;

[0042] Figure 4 Schematic diagram of the series side converter control of the control system disclosed in an embodiment of the present application;

[0043] Figure 5 is a flowchart of the smooth start control implementation disclosed in an embodiment of the present application. Detailed Embodiments

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0045] The embodiments described in the present invention are only a part of the embodiments of the present invention, rather than all of them. Based on the spirit of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0046] As Figure 1 shown, Embodiment 1 of the present invention proposes a UPFC dynamic simulation system, including a UPFC physical entity system, a UPFC digital twin system, a high-speed communication architecture, and an interconnection interface. The UPFC physical entity system includes a sending-end AC source , a receiving-end AC source , an upper DC bus U dc +, a lower DC bus U dc -, a sending-end line impedance X S , a receiving-end line impedance X R , a shunt transformer T sh , a series transformer T se , a shunt-side converter, a series-side converter, a first circuit breaker QF1, a second circuit breaker QF2, a third circuit breaker QF3, a fourth circuit breaker QF4, a first disconnecting switch DS1, a second disconnecting switch DS2, a third disconnecting switch DS3, a fourth disconnecting switch DS4, a fifth disconnecting switch DS5, a sixth disconnecting switch DS6, a seventh disconnecting switch DS7, an eighth disconnecting switch DS8, a fuse FU, and a thyristor bypass switch TBS;

[0047] The UPFC digital twin system is used to simulate, control, and provide application services for the UPFC physical entity system. The UPFC digital twin system includes a simulation model, a control system, a visualization interface, and an application service module;

[0048] The interconnection interface is used to realize data information interaction between the UPFC physical entity system and the UPFC digital twin system;

[0049] The simulation model simulates each physical component in the UPFC circuit under the conditions of electric field, thermal field and stress field, and the simulation model is used to be called by the control system and the application service module; the control system is used to control the UPFC physical entity system and the simulation model in the UPFC digital twin system, and obtain actual operation data and simulation operation data at the same time; the visualization interface is used to monitor and record the sequence control process of each converter, the real-time operation waveforms of the UPFC physical entity system and the UPFC digital twin system, and the system states of the UPFC physical entity system and the UPFC digital twin system;

[0050] The application service module is used for abnormal state diagnosis and analysis, fault location and early warning analysis, historical data replay and health state assessment.

[0051] Specifically, the application service module combines big data technology to analyze the data obtained from the operation of the UPFC physical entity system and the data obtained from the system dynamic simulation by calling the simulation model, and uses statistical methods such as regression analysis and time series analysis or machine learning methods based on artificial neural networks and deep learning to construct prediction models, decision models or evaluation models, and outputs the prediction, decision and evaluation results of the application service, revealing the future trend of the data, improving the reliability of decision-making and enhancing the multi-dimensional evaluation ability;

[0052] This embodiment evaluates the aging and life of the sub-modules of the UPFC physical entity system. The main component restricting the service life of the UPFC sub-module is the sub-module capacitor, and its key aging parameters are the sub-module capacitance value and the sub-module equivalent series resistance; the operation of the UPFC physical entity system and the UPFC digital twin system can obtain information such as DC bus voltage, AC side voltage / current, sub-module voltage and sub-module current, and establish a data set in the unit of year-month-day-hour-minute. A prediction model for the aging parameters of the sub-module capacitor is established by using the BP neural network and combining with the circuit principle, and the current sub-module capacitance value and the sub-module equivalent series resistance are obtained by using the data of the UPFC physical entity system as the input to train the prediction model, and the component parameters of the simulation model of the UPFC digital twin system are updated to obtain the sub-module life evaluation result at this time. On this basis, the future working conditions of the UPFC physical entity system can be simulated in the UPFC digital twin system, and the sub-module life prediction trend can be further obtained.

[0053] Preferably, the simulation model is divided into a basic model, an average model and a dynamic model according to the time scale. The static parameters of each physical component are simulated by the basic model, and the physical quantities of each physical component at a long time scale interval are simulated by the average model; the dynamic model additionally adds dynamic characteristics on the basis of the average model, including the on-off transient process of the switching tube.

[0054] The high-speed communication architecture includes several hosts and communication networks. The hosts are used to implement the converter process and its control in the UPFC physical entity system and to realize the various functions of the UPFC digital twin system. The communication network is used for communication between hosts.

[0055] Preferably, the hosts in the high-speed communication architecture include a parallel side converter host, a series side converter host, a protection service host, an intelligent auxiliary host, a first server, a second server and an operable host computer; the parallel side converter host is used to implement the parallel side converter sequential control process and its control, the series side converter host is used to implement the series side converter sequential control process and its control, the protection service host is used to implement converter protection, transformer protection and AC line protection, the intelligent auxiliary host is used to provide all functions of the UPFC digital twin system, the first server and the second server cooperate to implement communication functions, provide centralized computing, information publishing and data management services, and the operable host computer provides a friendly human-computer interaction interface.

[0056] Preferably, if Figure 2 As shown, the communication network of the high-speed communication architecture adopts dual LAN networking, including LAN1, a first LAN2, an RJ45 Ethernet interface, a second RJ45 Ethernet interface, a first Ethernet signal transformer, a second Ethernet signal transformer, a first MAC / PHY transceiver, a second MAC / PHY transceiver and a CPU, one end of the first RJ45 Ethernet interface is connected to LAN1, and the other end is connected to one end of the first Ethernet transformer, the other end of the first Ethernet transformer is connected to one end of the first MAC / PHY transceiver, and the other end of the first MAC / PHY transceiver is connected to the CPU; one end of the second RJ45 Ethernet interface is connected to LAN2, and the other end is connected to one end of the second Ethernet transformer 2, the other end of the second Ethernet transformer is connected to one end of the second MAC / PHY transceiver, and the other end of the second MAC / PHY transceiver is connected to the CPU.

[0057] Embodiment 2 of the present invention provides a control method for the UPFC dynamic model system described in Embodiment 1 of the present invention:

[0058] When the system only needs fast reactive power compensation, the series side does not work and the parallel side works in STATCOM mode; when the system needs to control power flow and voltage distribution and take into account dynamic reactive power compensation, the series side is connected and the parallel side runs in UPFC mode. When a system failure occurs, operational fault protection is performed;

[0059] like Figure 3 As shown, when in the STATCOM mode, the parallel side works in the grid-side AC voltage control; when in the UPFC mode, the parallel side works in the reactive power control; Figure 4As shown, the series side operates under line active power control and line reactive power control, and the series side performs line fault restart control; before the series side is connected, the series side executes smooth start control; the operation fault protection includes line protection, transformer protection, and UPFC body protection;

[0060] Preferably, as Figure 5 shown, the smooth start control is specifically as follows:

[0061] S1. Before starting, the states of each circuit breaker and disconnector are as follows: the first circuit breaker QF1 is open, the second circuit breaker QF2 is closed, the third circuit breaker QF3 is open, the fourth circuit breaker QF4 is closed, the first disconnector DS1 is open, the second disconnector DS2 is open, the third disconnector DS3 is open, the fourth disconnector DS4 is open, the fifth disconnector DS5 is open, the sixth disconnector DS6 is open, the seventh disconnector DS7 is open, the eighth disconnector DS8 is open, and the start parameters of the series side converter are set according to system requirements;

[0062] S2. Close the second disconnector DS2, the third disconnector DS3, the seventh disconnector DS7, the eighth disconnector DS8, the fifth disconnector DS5, the sixth disconnector DS6, and the fourth disconnector DS4 in sequence;

[0063] S3. Close the third circuit breaker QF3 to complete the charging of the primary winding of the series transformer T se ; open the fourth circuit breaker QF4 to complete the connection between the secondary winding of the series transformer T se and the series side converter;

[0064] S4. Close the first circuit breaker QF1. At the same time, the shunt side converter and the series side converter receive the start signal and start charging. At this time, the current loop of the series side converter uses the circuit transmission current i 1 as the reference value to control the output current of the series side converter i se to be close to the circuit transmission current i 1 converted to the secondary side. When the amplitude difference between the two is less than the set smooth access current threshold of the series side, it indicates that the charging is completed. Close the first disconnector DS1, then open the second circuit breaker QF2. At the same time, the reference value of its current loop is converted to the output of the voltage loop of the series side converter. At this time, the series side converter smoothly accesses the main circuit.

[0065] Specifically, the set smooth access current threshold of the series side is 1%;

[0066] Preferably, the setting of the start parameters of the series side converter according to system requirements includes the active power reference of the series side converter and the reactive power reference The smooth access current thresholds on the series side and the shunt side are the same as the set values during rated operating conditions. Preferably, the line fault restart control is specifically as follows: when a fault occurs, it is determined whether the fault is a line fault or a device fault. When it is determined to be a line fault, the thyristor bypass switch TBS is closed, the series-side converter is blocked, and the series-side converter is isolated from the main circuit and taken out of operation;

[0067] After passing through the reclosing setting time, which is the time set for the slave device to sense the breaker opening until the device is allowed to issue a closing command; by detecting the line voltage, current, and switch position, it is determined whether the line is operating normally. If it is normal, the thyristor bypass switch TBS is opened, and the series-side converter is restarted and put into operation again.

[0068] Preferably, the reclosing setting time is set between 0.8 - 2.0 s.

[0069] Preferably, the line protection, transformer protection, and UPFC body protection for the operation fault protection are specifically as follows: the line protection includes overvoltage protection and breaker protection; the transformer protection includes transformer electrical quantity protection and transformer non-electrical quantity protection; the UPFC body protection specifically includes shunt-side actions and series-side actions;

[0070] Shunt-side actions: alarm, switch the control system, block the shunt-side converter, trip the switch on the converter side of the shunt transformer, and trip the switch on the network side of the shunt transformer in case of failure;

[0071] Series-side actions: alarm, switch the control system, block the series-side converter, trigger the thyristor bypass switch TBS to conduct, close the bypass switch on the line side of the series transformer, and close the bypass switch on the converter side of the series transformer;

[0072] When the shunt side has a fault and trips the series side: for a fault in the series-side AC area, only the corresponding side converter is taken out of operation; for a fault in the series-side converter area, it trips the other side.

[0073] In summary, in view of the deficiencies of the prior art, the present invention provides a UPFC dynamic simulation system, a high-speed communication architecture, and a control method. A twin model corresponding to the UPFC physical entity is constructed based on digital twin technology; the high-speed communication architecture using dual-LAN networking can aggregate the bandwidths of two or more LAN interfaces, thereby providing higher network throughput capacity and effectively improving the data transmission speed; the provided control method can meet the requirements for the operation, protection, etc. of the UPFC in actual engineering, and has advantages such as multiple functions, high communication efficiency, and high intelligence level.

[0074] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or terminal device comprising the said element.

[0075] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A UPFC dynamic simulation system, comprising a UPFC physical entity system, a UPFC digital twin system and an interconnection interface, wherein the UPFC physical entity system includes a sending-end AC source , a receiving-end AC source , an upper DC bus U dc +, a lower DC bus U dc -, a sending-end line impedance X S , a receiving-end line impedance X R , a shunt transformer T sh , a series transformer T se , a shunt-side converter, a series-side converter, a first circuit breaker QF1, a second circuit breaker QF2, a third circuit breaker QF3, a fourth circuit breaker QF4, a first disconnector DS1, a second disconnector DS2, a third disconnector DS3, a fourth disconnector DS4, a fifth disconnector DS5, a sixth disconnector DS6, a seventh disconnector DS7, an eighth disconnector DS8, a fuse FU and a thyristor bypass switch TBS; characterized in that: The UPFC digital twin system is used to simulate, control, and provide application services for the UPFC physical entity system. The UPFC digital twin system includes a simulation model, a control system, a visualization interface, and an application service module; The interconnection interface is used to realize data information interaction between the UPFC physical entity system and the UPFC digital twin system; The simulation model simulates each physical component in the UPFC circuit under the conditions of electric field, thermal field, and stress field. The simulation model is used for the control system and the application service module to call. The control system is used for the control of the UPFC physical entity system and the control of the simulation model in the UPFC digital twin system, and at the same time obtains actual operation data and simulation operation data. The visualization interface is used to monitor and record the structure of the UPFC physical entity system, the sequence control process of each converter, the real-time operation waveforms of the UPFC physical entity system and the UPFC digital twin system, and the system status of the UPFC physical entity system and the UPFC digital twin system; The application service module is used for abnormal state diagnosis and analysis, fault location and early warning analysis, historical data replay, and health state assessment; respectively obtain information such as DC bus voltage, AC side voltage / current, sub-module voltage, and sub-module current when the UPFC physical entity system and the UPFC digital twin system are running, and establish a data set in the unit of year-month-day-hour-minute. Adopt a BP neural network to establish a prediction model for the aging parameters of the sub-module capacitor, and use the data of the UPFC physical entity system as input to train the prediction model to obtain the current sub-module capacitor value and the sub-module equivalent series resistance, and update the corresponding aging parameters of the simulation model of the UPFC digital twin system to obtain the sub-module life assessment result. Simulate the future working conditions of the UPFC physical entity system in the UPFC digital twin system to obtain the sub-module life prediction trend; The simulation model is divided into a basic model, an average model, and a dynamic model according to the time scale. The static parameters of each physical component are simulated by the basic model, and the physical quantities of each physical component at a long time scale interval are simulated by the average model. The dynamic model additionally adds dynamic characteristics on the basis of the average model, including the on-off transient process of the switching tube.

2. The UPFC dynamic simulation system according to claim 1, wherein: The host in the high-speed communication architecture includes a shunt converter host, a series converter host, a protection service host, an intelligent auxiliary host, a first server, a second server, and an operable upper computer. The shunt converter host is used to realize the sequence control process and its control of the shunt converter. The series converter host is used to realize the sequence control process and its control of the series converter. The protection service host is used to realize converter protection, transformer protection, and AC line protection. The intelligent auxiliary host is used to provide all functions of the UPFC digital twin system. The first server and the second server cooperate to realize communication functions and provide services such as centralized computing, information publishing, and data management. The operable upper computer provides a friendly human-computer interaction interface.

3. A high-speed communication architecture for the moving die system according to any one of claims 1-2, characterized in that: The high-speed communication architecture includes a number of hosts and a communication network. The hosts are used to implement the converter process and its control in the UPFC physical entity system and to implement the various functions of the UPFC digital twin system. The communication network is used for communication between the hosts; The communication network of the high-speed communication architecture uses a dual-LAN network, including LAN1, the first LAN2, RJ45 Ethernet interfaces, the second RJ45 Ethernet interface, the first Ethernet signal transformer, the second Ethernet signal transformer, the first MAC / PHY transceiver, the second MAC / PHY transceiver, and the CPU. One end of the first RJ45 Ethernet interface is connected to LAN1, and the other end is connected to one end of the first Ethernet transformer. The other end of the first Ethernet transformer is connected to one end of the first MAC / PHY transceiver. The other end of the first MAC / PHY transceiver is connected to the CPU; One end of the second RJ45 Ethernet interface is connected to LAN2, and the other end is connected to one end of the second Ethernet transformer 2. The other end of the second Ethernet transformer is connected to one end of the second MAC / PHY transceiver. The other end of the second MAC / PHY transceiver is connected to the CPU.

4. A control method applied to the UPFC moving die system according to any one of claims 1-2, characterized in that: When the system only needs fast reactive power compensation, the series side does not work, and the shunt side operates in the STATCOM mode; when the system needs to control the power flow, voltage distribution and take into account dynamic reactive power compensation, the series side is connected and the shunt side operates in the UPFC mode. When a fault occurs in the system, operation fault protection is performed; When in the STATCOM mode, the shunt side operates in grid-side AC voltage control; when in the UPFC mode, the shunt side operates in reactive power control; the series side operates under line active power control and line reactive power control, and the series side performs line fault restart control; before the series side is connected, the series side performs smooth start control; the operation fault protection includes line protection, transformer protection and UPFC body protection.

5. The control method of a UPFC dynamic simulation system according to claim 4, characterized in that : The smooth start control is specifically as follows: S1. Before starting, the states of each circuit breaker and disconnector are as follows: the first circuit breaker QF1 is open, the second circuit breaker QF2 is closed, the third circuit breaker QF3 is open, the fourth circuit breaker QF4 is closed, the first disconnector DS1 is open, the second disconnector DS2 is open, the third disconnector DS3 is open, the fourth disconnector DS4 is open, the fifth disconnector DS5 is open, the sixth disconnector DS6 is open, the seventh disconnector DS7 is open, the eighth disconnector DS8 is open. Set the start parameters of the series-side converter according to the system requirements; S2. Close the second disconnector DS2, the third disconnector DS3, the seventh disconnector DS7, the eighth disconnector DS8, the fifth disconnector DS5, the sixth disconnector DS6, and the fourth disconnector DS4 in sequence; S3. Close the third circuit breaker QF3 to complete the charging of the primary winding of the series transformer T se ; disconnect the fourth circuit breaker QF4 to complete the connection between the secondary winding of the series transformer T se and the series-side converter; S4. Close the first circuit breaker QF1. Meanwhile, the shunt-side converter and the series-side converter receive the start signal and start charging. At this time, the current loop of the series-side converter uses the circuit transmission current i 1 as the reference value to control the output current of the series-side converter i se to approach the circuit transmission current converted to the secondary side i 1. When the amplitude difference between the two is less than the set smooth access current threshold of the series side, it indicates that the charging is completed. Then close the first disconnector DS1, and then disconnect the second circuit breaker QF2. Meanwhile, the reference value of its current loop is converted to the output of the voltage loop of the series-side converter. At this time, the series-side converter smoothly accesses the main circuit.

6. The control method of a UPFC dynamic simulation system according to claim 5, wherein : The setting of the start-up parameters of the series-side converter according to the system requirements includes the active power reference of the series-side converter , the reactive power reference of the series-side converter and the smooth access current threshold of the series side. The set values of both are the same as those in the rated operating conditions.

7. The control method of a UPFC dynamic simulation system according to claim 4, characterized in that: The line fault restart control is specifically as follows: when a fault occurs, it is judged whether the fault is a line fault or an equipment fault. When it is judged as a line fault, the thyristor bypass switch TBS is closed, and the series-side converter is blocked to isolate the series-side converter from the main circuit and withdraw it from operation; After the reclosing setting time, the reclosing setting time is set as the time from when the slave device senses the opening of the circuit breaker to when the device allows the issuance of a closing command; By detecting the line voltage, current and switch position, it is judged whether the line is operating normally. If it is normal, the thyristor bypass switch TBS is opened, and the series-side converter is restarted and put into operation again.

8. The control method of a UPFC dynamic simulation system according to claim 7, characterized in that: The reclosing setting time is set between 0.8 - 2.0 s.

9. The control method of a UPFC dynamic simulation system according to claim 4, characterized in that: The line protection, transformer protection and UPFC body protection of the operation fault protection are specifically as follows: the line protection includes overvoltage protection and circuit breaker protection; the transformer protection includes transformer electrical quantity protection and transformer non-electrical quantity protection; the UPFC body protection specifically includes parallel-side actions and series-side actions; Parallel-side actions: alarm, switching the control system, blocking the parallel-side converter, tripping the parallel-side transformer converter-side switch, and malfunction tripping the parallel-side transformer grid-side switch; Series-side actions: alarm, switching the control system, blocking the series-side converter, triggering the thyristor bypass switch TBS to conduct, closing the series-side transformer line-side bypass switch, and closing the series-side transformer converter-side bypass switch; Parallel-side fault tripping the series-side: in case of a fault in the series-side AC area, only the converter on the corresponding side is withdrawn; in case of a fault in the series-side converter area, it trips the other side.

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