An online verification system for stable control strategy of high-proportion new energy system

Abstract

The present invention discloses an online verification system for a high-proportion new energy system stability control strategy. The system is based on an established real-time simulation system, a stability control system substation custom module, and a stability control system master station hardware device for interconnected communication, and a stability control strategy simulation verification. The real-time simulation system performs digital modeling on the dynamic model data of a large power grid including power electronic equipment such as direct current and new energy, and the stability control system substation custom module realizes data interaction and sharing between the real-time simulation system and the stability control system master station hardware device. The stability control system master station hardware device obtains the substation information in real time through Ethernet, executes the corresponding stability control strategy after receiving the power grid fault information, and realizes a closed-loop simulation test with the real-time simulation system.

Description

Technical Field

[0001] The present invention belongs to the field of power systems, and relates to a test technology for a safe and stable control system of a power system, and specifically to an online verification system for a stable control strategy of a high-proportion new energy system and an implementation method thereof. Background Art

[0002] In order to meet the strategic goal of "transmitting electricity from west to east", a high proportion of new energy access to the UHV DC system at the sending end is a powerful measure to achieve my country's energy strategy and realize the long-distance transmission of clean energy across regions. However, the increase in the penetration rate of new energy has also greatly increased the difficulty of power grid operation, especially the poor grid-related performance of new energy power generation systems with power electronic interfaces, resulting in increasingly severe situations for safe and stable operation of the system, and increasingly complex stability control strategies.

[0003] The safety and stability control system (referred to as "stability control system") is an important line of defense to ensure the safe and stable operation of the power grid. In the implementation of existing stability control projects, there is the pressure of verifying complex stability control strategies in complex systems. In particular, the substantial changes in the output of renewable energy sources during the day will cause significant changes in the operation mode of the system. Therefore, it is particularly important to verify the correctness of the stability control strategy. In terms of stability control strategy verification, how to achieve online verification and correct the amount of stability control measures is the key to improving the accuracy and adaptability of the stability control strategy. When applied in large power grids, the problem is often faced that the huge scale of the power grid causes the number of communication interfaces required to far exceed the software and hardware limitations. Therefore, it is urgent to explore optimization methods and systems that can reduce the software and hardware resources required for system communication while ensuring the accuracy of strategy verification, so as to improve the work efficiency of stability control strategy verification. Summary of the invention

[0004] The object of the present invention is to provide an online verification system for a stability control strategy of a high-proportion new energy system, which is used to realize online simulation verification of a stability control strategy suitable for a high-proportion new energy access system.

[0005] Technical solution: An online verification system for the stability control strategy of a high-proportion new energy system, including a real-time simulation system, a custom module for a stability control substation, and a hardware device for a stability control main station;

[0006] The real-time simulation system is based on the EMS real-time data and state estimation results, and modifies the current large power grid simulation model as the basic model, automatically matching the preset fault set and stabilization strategy set;

[0007] The custom module of the stabilization and control substation samples the instantaneous values ​​of voltage and current at each acquisition point in the digital model of the real-time simulation system, obtains the three-phase voltage, current effective value, active power, reactive power, system frequency and switch position signals through data processing and calculation, and realizes information interaction with the hardware device of the stabilization and control main station;

[0008] The hardware device of the stabilization control master station is distributedly arranged at the substation end, and the system operation mode is judged according to the electrical quantity and switch quantity signals uploaded by the custom module of the stabilization control substation, and the strategy is matched according to the output of different types of new energy, and the stabilization control instruction is issued after the simulated fault;

[0009] The real-time simulation system establishes communication with the custom module of the stabilization control substation and the hardware device of the stabilization control main station through a fast communication dedicated network.

[0010] In this system, the real-time simulation system is arranged at the dispatching end of the new energy system and interconnected with the EMS system, including transient digital modeling and simulation of the current operation mode of the high-proportion new energy system based on the state estimation and calculation results of the EMS system.

[0011] The real-time simulation model establishes a large power grid simulation model based on the radiation area of ​​the energy system, and the area includes regional power grids at provincial or municipal levels for dynamic equivalence;

[0012] The dynamic equivalent method includes synchronous equivalent, modal equivalent, and estimated equivalent. The assessment standard is that after a preset fault occurs, the errors of the voltage and frequency of the key buses of the two systems before and after the equivalent, and the active and reactive output of the key units are within the specified range;

[0013] The equivalent error is defined as:

[0014]

[0015] Among them, M is the number of faults to be assessed, L is the number of key nodes and key units, T is the simulation time, and X is the number of critical nodes and units. j (t) 等值前 , X j (t) 等值后 They are respectively the voltage response of the key nodes before and after the equal value at time t or the active and reactive responses of the key units at time t.

[0016] Furthermore, the preset fault set in the system includes DC commutation failure, DC lockout, line N-2, and main transformer N-2 faults; the stabilization control strategy set is calculated based on offline simulation software, including the operating mode, preset faults and corresponding stabilization control measures.

[0017] The operation mode is divided into combinations according to the current operating power of DC and different threshold values ​​of different types of new energy output in different regions.

[0018] Furthermore, the custom module of the stabilization and control substation reduces the number of communication interfaces required between the real-time simulation system and the stabilization and control hardware device through digital modeling, and realizes simulation based on the custom modeling function or C language interface function of the real-time simulation system.

[0019] The hardware device of the stabilization control main station sends stabilization control instructions to the real-time simulation system according to the fault information and electrical quantity and switch quantity signals uploaded by the custom module of the stabilization control substation and the stabilization control strategy set.

[0020] Furthermore, the stability control instruction needs to check the actual machine cutting and load cutting amount after completing a single simulation and compare it with the actual stability control strategy. After the comparison is in line with the existing strategy, the frequency, voltage and unit power angle response curve of the real-time simulation system are further combined to judge the system stability;

[0021] If the amount of measures to cut machine loads cannot meet the safety and stability requirements of the system after verification by the real-time simulation system, it is necessary to further increase the amount of measures, carry out offline special simulation calculations, and revise the stability control strategy.

[0022] The fast communication private network refers to a fast optical fiber communication network specially established for the online verification system of the stability control strategy of a high-proportion new energy system. The communication protocols used include the GOOSE transmission protocol of IEC61850 and the HDLC communication protocol.

[0023] Based on the above system, the present invention provides a method for implementing an online verification system for a high-proportion new energy system stability control strategy, including building a real-time simulation system, and verifying the temperature control strategy by interconnecting and communicating with the hardware device of the stability control master station in coordination with the custom module of the stability control substation. The implementation method includes the following steps:

[0024] (1) constructing a real-time simulation system, wherein the real-time simulation system performs digital modeling based on the regional large power grid, and based on the EMS real-time data and state estimation results, corrects the current large power grid simulation model as the basic model, and automatically matches the preset fault set and stability control strategy set;

[0025] (2) Based on the sampling of the instantaneous values ​​of voltage and current at each acquisition point in the digital model of the real-time simulation system, the three-phase voltage, current effective value, active power, reactive power, system frequency and switch position signals are obtained through data processing and calculation, and information interaction is achieved with the hardware device of the stabilization control master station;

[0026] (3) The hardware device of the stabilization control master station is distributed in the relevant substations, and the system operation mode is judged according to the electrical quantity and switch quantity signals uploaded by the custom module of the stabilization control substation, and the strategy is matched according to the output of different types of new energy, and the stabilization control command is issued after the simulated fault;

[0027] (4) After completing a single simulation, the stability control command needs to verify the actual amount of machine cutting and load shedding and compare it with the actual stability control strategy. After the comparison is consistent with the existing strategy, it is further combined with the frequency, voltage and unit power angle response curve of the real-time simulation system to judge the system stability. If the amount of machine cutting and load shedding measures cannot meet the safety and stability requirements of the system after verification by the real-time simulation system, it is necessary to further increase the amount of measures, carry out offline special simulation calculations, and correct the stability control strategy.

[0028] Beneficial effects: The present invention conducts digital modeling of large power grids, obtains the current power grid operation mode in real time through the EMS system and state estimation, and realizes information interaction between the digital model and the actual control device of the control station through the custom module of the control station, which can save communication interface resources while ensuring the accuracy of the control verification. The online verification system of the high-proportion new energy system control strategy proposed by the present invention can effectively verify the adaptability of the control strategy to the system with complex dynamic characteristics, and improve the safe and stable operation level of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural diagram of the real-time verification system for the high-proportion new energy system stability control strategy described in the present invention. DETAILED DESCRIPTION

[0030] To illustrate the technical solution disclosed by the present invention in detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The present invention provides an online verification system for the stability control strategy of a high-proportion new energy system. The system is based on an established real-time simulation system to interconnect and communicate with a custom module of a stability control substation and a hardware device of a stability control main station, and simulate and verify the temperature control strategy. The real-time simulation system digitally models the dynamic model data of a large power grid including power electronic equipment such as DC and new energy, and the custom module of the stability control substation realizes data interaction and sharing between the real-time simulation system and the hardware device of the stability control main station. The hardware device of the stability control main station obtains the information of the stability control substation in real time through Ethernet, executes the corresponding stability control strategy after receiving the power grid fault information, and realizes a closed-loop simulation test with the real-time simulation system.

[0032] As shown in the figure, Figure 1 The structure diagram of the online verification system of the stability control strategy of a high-proportion new energy system of the present invention is shown. The online verification system of the stability control strategy of a high-proportion new energy system includes a real-time simulation system, a custom module of a stability control substation, and a hardware device of a stability control main station. A dedicated fast optical fiber communication network is established between the three, and the communication protocols used include the GOOSE transmission protocol of IEC61850 and the HDLC communication protocol.

[0033] Furthermore, the real-time simulation system conducts digital modeling of the large power grid data, and the custom module of the stabilization control substation realizes data interaction and sharing between the real-time simulation system and the hardware device of the stabilization control main station. The hardware device of the stabilization control main station obtains the information of the stabilization control substation in real time through Ethernet, and executes the corresponding stabilization control strategy after receiving the power grid fault information, realizing closed-loop simulation testing with the real-time simulation system.

[0034] Specifically, the real-time simulation system digitally models the large power grid, and based on the real-time data and state estimation results of the EMS, it modifies the current large power grid simulation model as the basic model, and automatically matches the preset fault set and stability control strategy set. The real-time simulation system is set at the dispatching end of the high-proportion new energy system, communicates and obtains information with the existing EMS system, and performs transient digital modeling of the current operation mode of the system based on the state estimation calculation results. The above includes the construction of the real-time simulation system model, the large power grid simulation model, and its modeling scope can include the entire regional power grid, and can also be dynamically equivalent to a provincial power grid. The main purpose of dynamic equivalence is to simplify the local power grid and reduce the scale of simulation calculations. Dynamic equivalence methods include synchronous equivalence, modal equivalence, and estimated equivalence. The assessment standard is that after the occurrence of a preset fault, the voltage, frequency, active and reactive output errors of the key buses of the two systems before and after the equivalence are within the specified range;

[0035] The equivalent error is defined as:

[0036]

[0037] Among them, M is the number of faults to be assessed, L is the number of key nodes and key units, T is the simulation time, and X is the number of critical nodes and units. j (t) 等值前 , X j (t) 等值后 They are respectively the voltage response of the key node at time t before and after the equalization or the active and reactive power response of the key unit at time t. The active and reactive power errors after the equalization are smaller than the above values.

[0038] The preset fault set, including DC commutation failure, DC lockout, line N-2, main transformer N-2 and other faults, should include the system fault set considered by all stabilization strategies. The stabilization strategy set is calculated based on offline simulation software, including the operating mode, preset faults and corresponding stabilization measures. The operating mode is divided into combinations based on the current operating power of DC and the different threshold values ​​of different types of new energy output in different regions. Taking the system divided into areas A and B as an example, the system operating mode is divided according to the following table:

[0039]

[0040] In the above table, the first number represents the operation mode, and the second number represents the different outputs. The operation mode is the combination of mode x and power x. Line N-2 and main transformer N-2 are both out of service due to faults.

[0041] The custom module of the stabilization and control substation is based on the sampling of the instantaneous values ​​of voltage and current at each acquisition point in the digital model of the real-time simulation system, and obtains the three-phase voltage, current effective value, active power, reactive power, system frequency and switch position signals through data processing and calculation, and realizes information interaction with the hardware device of the stabilization and control main station. The custom module of the stabilization and control substation reduces the number of communication interfaces required between the real-time simulation system and the stabilization and control hardware device through digital modeling, and can realize simulation based on the custom modeling function of the real-time simulation system or the C language interface function;

[0042] The hardware device of the stabilization and control master station is distributed in the relevant substations. It determines the system operation mode according to the electrical quantity and switch quantity signals uploaded by the custom module of the stabilization and control substation, matches the strategy according to the output of different types of new energy, and issues stabilization and control instructions after simulating a fault. In the hardware device of the stabilization and control master station, according to the fault information and electrical quantity, switch quantity and other signals uploaded by the custom module of the stabilization and control substation, according to the stabilization and control strategy set, stabilization and control instructions are issued to the real-time simulation system, such as signals of cutting machine and load.

[0043] The stability control instructions need to verify the actual machine and load shedding after completing a single simulation and compare them with the actual stability control strategy. After the comparison is in line with the existing strategy, the frequency, voltage and unit power angle response curve of the real-time simulation system are further combined to judge the system stability. If the machine and load shedding measures cannot meet the safety and stability requirements of the system after verification by the real-time simulation system, the measures need to be further increased, and offline special simulation calculations need to be carried out to correct the stability control strategy.

[0044] Combined with the above-mentioned process of the system and simulation modeling of the present invention, a more specific description is given. The EMS system is a general term for modern power grid dispatching automation systems (including hardware and software), which are composed of two parts: basic functions and application functions. The basic functions include computers, operating systems and EMS support systems. The method described in the present invention first adopts state estimation based on the EMS system, that is, according to the real-time information provided by SCADA and the analysis results of the network topology and other relevant data, the voltage of each bus in the power grid, the flow of each branch such as lines and transformers, the load of each bus and the output characteristics of each generator are given in real time to build a real-time online simulation model of the power grid. Based on the real-time simulation system, the detection and identification of bad data are realized, and the maintenance of the bus load prediction model and the measurement error statistics are realized. In the real-time simulation system, we set the logical fault variables in the power grid, that is, the preset fault set and the stable control strategy set. Further, according to the application function level in the EMS system, the simulation verification of the stable control substation custom module and the stable control main station hardware device is carried out. In the verification process, different processing combinations of the operation mode are included, and the operation mode of the power system is combined to verify the stable control strategy, and the stable control strategy is adjusted according to the fault.

[0045] The technical solution provided by the present invention is based on the existing EMS system, and is based on the information interaction between digital simulation and stabilization control devices and stabilization control strategies, so as to realize real-time verification of stabilization control strategies, improve the accuracy of stabilization control strategies, and provide support for the safe and stable operation of the power grid. The system and verification method described in the present invention provide a solution for the real-time verification of complex stabilization control strategies for the access of a large proportion of new energy to the large power grid. The custom modeling of the stabilization control substation greatly saves communication interface resources, avoids direct information interaction with the massive hardware devices of the stabilization control substation, and focuses the stabilization control test on the correctness of the stabilization control strategy, realizing the dynamic interaction between the simulation of the large power grid and the stabilization control strategy, and improving the adaptability of the stabilization control strategy. In addition, the real-time verification system of the stabilization control strategy reduces the amount of interface information of the real-time simulation system for the stabilization control hardware device by custom modeling the stabilization control substation function, and interacts with the hardware device of the stabilization control main station to realize online verification of the stabilization control strategy and verify the correctness of the stabilization control measures.

Claims

1. An online verification system for a high-proportion new energy system stability control strategy, characterized in that: It includes real-time simulation system, custom module of stability control system substation and hardware device of stability control system master station; The real-time simulation system is arranged at the dispatching end of the new energy system and interconnected with the EMS system, including transient digital modeling and simulation of the current operation mode of the high-proportion new energy system according to the state estimation and calculation results of the EMS system, and based on the real-time data and state estimation results of the EMS, and correcting the current large power grid simulation model as the basic model, automatically matching the preset fault set and stable control strategy set; The substation custom module of the stability control system is based on the sampling of the instantaneous values ​​of voltage and current at each acquisition point in the digital model of the real-time simulation system, and obtains the three-phase voltage, current effective value, active power, reactive power, system frequency and switch position signals through data processing and calculation, and realizes information interaction with the hardware device of the main station of the stability control system; The hardware device of the main station of the stability control system is distributedly arranged at the substation end, and the system operation mode is judged according to the electrical quantity and switch quantity signals uploaded by the custom module of the substation of the stability control system, and the strategy is matched according to the output of different types of new energy, and the stability control command is issued after the simulated fault; The real-time simulation system establishes communication with the custom module of the stability control system substation and the hardware device of the stability control system main station through a fast communication dedicated network; The mathematical model of the real-time simulation system is to establish a large power grid simulation model based on the radiation area of ​​the new energy system, and the area includes a regional power grid at the provincial or municipal level for dynamic equivalence; The dynamic equivalent includes synchronous equivalent, modal equivalent, and estimated equivalent. The assessment standard is that after a preset fault occurs, the error of the voltage and frequency of the key buses of the two systems before and after the equivalent, and the active and reactive output of the key units are within the specified range; The equivalent error is defined as: Among them, M is the number of faults to be assessed, L is the number of key nodes and key units, T is the simulation time, and X is the number of critical nodes and units. j (t) 等值前 , X j (t) 等值后 They are respectively the voltage response of the key nodes before and after the equal value at time t or the active and reactive responses of the key units at time t.

2. The high-proportion new energy system stability control strategy online verification system according to claim 1 is characterized in that: The preset fault set includes DC commutation failure, DC blocking, line N-2, and main transformer N-2 faults.

3. The high-proportion new energy system stability control strategy online verification system according to claim 1 is characterized in that: The stability control strategy set is calculated based on offline simulation software, including the operating mode, preset faults and corresponding stability control measures.

4. The high-proportion new energy system stability control strategy online verification system according to claim 3 is characterized in that: The operation mode is divided into combinations according to the current operating power of DC and different threshold values ​​of different types of new energy output in different regions.

5. The high-proportion new energy system stability control strategy online verification system according to claim 1 is characterized by: The described stability control system substation custom module reduces the number of communication interfaces required between the real-time simulation system and the stability control system hardware device through digital modeling, and implements simulation based on the custom modeling function of the real-time simulation system or the C language interface function.

6. The high-proportion new energy system stability control strategy online verification system according to claim 1 is characterized by: The hardware device of the main station of the stability control system issues a stability control instruction to the real-time simulation system according to the fault information and electrical quantity and switch quantity signals uploaded by the custom module of the substation of the stability control system and the stability control strategy set.

7. The high-proportion new energy system stability control strategy online verification system according to claim 6 is characterized by: The stability control instruction needs to check the actual machine and load shedding after completing a single simulation and compare it with the actual stability control strategy. After the comparison is in line with the existing strategy, the frequency, voltage and unit power angle response curve of the real-time simulation system are further combined to judge the system stability; If the amount of machine or load shedding measures cannot meet the system safety and stability requirements after verification by the real-time simulation system, it is necessary to further increase the amount of measures, carry out offline special simulation calculations, and correct the stability control strategy.

8. The high-proportion new energy system stability control strategy online verification system according to claim 1 is characterized by: The fast communication private network refers to the optical fiber communication network established by the online verification system of the high-proportion new energy system stability control strategy, and the communication protocols adopted include the GOOSE transmission protocol of IEC61850 and the HDLC communication protocol.

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