An online simulation method and system for an LCC DC transmission electro-electromagnetic hybrid system

Abstract

The present invention discloses an online simulation method and system for an LCC DC transmission electromechanical-electromagnetic hybrid system, including: building a primary system circuit and a secondary control system model of a DC transmission system based on an electromagnetic transient simulation program, and encapsulating the two into a DC submodule called by electromechanical transient simulation; performing equivalent processing of the electromechanical transient full network on the DC submodule and the DC submodule on the electromechanical transient full network respectively; realizing data exchange between the electromechanical transient full network and the DC submodule through an equivalent circuit, and the electromechanical transient full network and the DC submodule call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation. The present invention solves the problem that the transient characteristics of DC transmission equipment cannot be accurately simulated in electromechanical transient simulation and that electromagnetic transient simulation is difficult to simulate large-scale AC and DC power grids, realizes the parallel calculation of the electromechanical transient full network and the DC submodule under steady-state conditions, and ensures the calculation speed and accuracy of the simulation when calling the submodule.

Description

Technical Field

[0001] The present invention relates to the technical field of electromechanical transient simulation, and more specifically, to an online simulation method and system for an LCC direct current transmission motor-electromagnetic hybrid system. Background Art

[0002] High-voltage direct current transmission equipment has the ability to respond quickly to system disturbances. The electromechanical transient simulation program uses a quasi-steady-state model for HVDC devices, so it cannot simulate the transient voltage and current response of the device interface or the internal part. Although the electromagnetic transient simulation program can accurately simulate the transient characteristics of complex direct current transmission equipment, it is limited by the computing and storage capacity of computers. Even with the parallel algorithm, it is difficult to perform electromagnetic transient simulation of the entire large-scale power system. The current hybrid simulation algorithm requires the establishment of electromagnetic transient models of HVDC and its controller in the program. Different devices and different control strategies require different programs to be compiled, which lacks versatility. In addition, the process of building hybrid simulation examples is cumbersome, which affects the efficiency of large-scale AC and DC power grid simulation analysis. The electromagnetic transient program ETSDAC in ADPSS can flexibly establish a model of the DC transmission system, construct a simulation system in a full graphical interface without compiling electromagnetic transient simulation code, encapsulate the DC model and make it have certain versatility and independence, becoming a DC submodule in electromechanical transient simulation, which can be extended to any AC / DC hybrid system to simulate the DC transmission system in the electromechanical transient simulation process. Summary of the invention

[0003] The present invention provides an online simulation method and system for an LCC direct current transmission motor electromechanical electromagnetic hybrid system, so as to solve the problem of how to realize the online simulation of electromechanical electromagnetic hybrid.

[0004] In order to solve the above problem, according to one aspect of the present invention, an online simulation method for an LCC DC transmission machine electric-electromagnetic hybrid system is provided, the method comprising:

[0005] Based on the electromagnetic transient simulation program, the primary system circuit and secondary control system models of the DC transmission system are built, and the two are encapsulated as DC sub-modules called by electromechanical transient simulation;

[0006] The equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network are respectively performed;

[0007] Data exchange between the electromechanical transient full network and the DC submodule is realized through equivalent circuits. The electromechanical transient full network and the DC submodule call each other according to the preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation.

[0008] Preferably, the equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network respectively includes:

[0009] When calculating the internal network of the DC submodule, the Thevenin equivalent is performed on the entire electromechanical transient network to obtain the power frequency equivalent impedance array of the entire electromechanical transient network and the positive, negative, and zero-sequence equivalent potentials of the boundary points to provide them to the DC submodule;

[0010] When calculating the entire electromechanical transient network, the Norton equivalent is performed on the DC submodule to obtain the equivalent admittance matrix of the DC submodule and the positive, negative, and zero-sequence currents and voltages of the boundary points to provide them to the entire electromechanical transient network.

[0011] Preferably, the data exchange between the electromechanical transient full network and the DC submodule is realized by the equivalent circuit, and the electromechanical transient full network and the DC submodule call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation, including:

[0012] Step 1: The electromechanical transient network obtains the Thevenin equivalent impedance and equivalent potential of the boundary points and transmits them to the DC submodule;

[0013] Step 2: The DC submodule uses the acquired Thevenin equivalent impedance and equivalent potential of the boundary points to calculate the current cycle [T i ,T i+1 ] calculation of the step length of an electromagnetic transient simulation;

[0014] Step 3, calculate the current period [T i ,T i+1 ] at the end time T i+1 When the DC submodule completes the calculation of one electromagnetic transient simulation step, the current cycle [T i ,T i+1 ] is used to calculate the fundamental effective values ​​of the voltage and current at the boundary points based on the calculation results of one cycle, and the fundamental effective values ​​of the voltage and current at the boundary points are sent to the electromechanical transient network for simulation calculation; at the same time, the Davy equivalent impedance and equivalent potential of the electromechanical transient network are obtained again from the simulation calculation process of the electromechanical transient network;

[0015] Step 4: The electromechanical transient network uses the fundamental effective values ​​of the voltage and current at the boundary points to perform the current cycle [T i ,T i+1 ]; at the same time, the DC submodule calculates the electromagnetic transient simulation step length of the next cycle according to the Thevenin equivalent impedance and equivalent potential of the boundary points of the entire electromechanical transient network;

[0016] Step 5: Determine whether the system topology has changed. If so, the simulation ends. Otherwise, use Ti =T i +△T, update the simulation period, and return to step 3; where △T is the simulation step length.

[0017] Preferably, the method further comprises:

[0018] When the electromagnetic transient calculation network is in T n When a fault occurs at the moment, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process does not start the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until T n+2 time, calculate a cycle period [T n ,T n+2 ] and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, two steps of calculation are performed continuously until T n+1 Moment, from T n+1 From this moment on, the interface timing of the two computing processes is restored to the basic switching timing until the next network topology change or the end of the simulation.

[0019] Preferably, the electromagnetic transient simulation program is ADPSS-ETSDAC.

[0020] According to another aspect of the present invention, an online simulation system for an LCC DC transmission machine electro-electromagnetic hybrid system is provided, the system comprising:

[0021] A simulation model building unit is used to build a primary system circuit and a secondary control system model of a DC power transmission system based on an electromagnetic transient simulation program, and encapsulate the two into a DC submodule called by an electromechanical transient simulation;

[0022] An equivalent processing unit, used for respectively performing equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network;

[0023] The hybrid simulation unit is used to realize data exchange between the electromechanical transient full network and the DC sub-module through equivalent circuits. The electromechanical transient full network and the DC sub-module call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation.

[0024] Preferably, the equivalent processing unit performs equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network, respectively, including:

[0025] When calculating the internal network of the DC submodule, the Thevenin equivalent is performed on the entire electromechanical transient network to obtain the power frequency equivalent impedance array of the entire electromechanical transient network and the positive, negative, and zero-sequence equivalent potentials of the boundary points to provide them to the DC submodule;

[0026] When calculating the entire electromechanical transient network, the Norton equivalent is performed on the DC submodule to obtain the equivalent admittance matrix of the DC submodule and the positive, negative, and zero-sequence currents and voltages of the boundary points to provide them to the entire electromechanical transient network.

[0027] Preferably, the hybrid simulation unit realizes data exchange between the electromechanical transient full network and the DC submodule through an equivalent circuit, and the electromechanical transient full network and the DC submodule call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation, including:

[0028] Thevenin equivalent impedance and potential acquisition subunit, used to enable the electromechanical transient whole network to acquire the Thevenin equivalent impedance and equivalent potential of the boundary points and pass them to the DC submodule;

[0029] The electromagnetic transient simulation calculation subunit is used to enable the DC submodule to use the acquired Thevenin equivalent impedance and equivalent potential of the boundary points to perform the current cycle [T i ,T i+1 ] calculation of the step length of an electromagnetic transient simulation;

[0030] The voltage and current fundamental effective value acquisition subunit is used to calculate the current cycle [T i ,T i+1 ] at the end time T i+1 When the DC submodule completes the calculation of one electromagnetic transient simulation step, the current cycle [T i ,T i+1 ] is used to calculate the fundamental effective values ​​of the voltage and current at the boundary points based on the calculation results of one cycle, and the fundamental effective values ​​of the voltage and current at the boundary points are sent to the electromechanical transient network for simulation calculation; at the same time, the Davy equivalent impedance and equivalent potential of the electromechanical transient network are obtained again from the simulation calculation process of the electromechanical transient network;

[0031] The electromechanical transient simulation subunit is used to make the electromechanical transient network use the fundamental effective values ​​of the voltage and current at the boundary points to perform the current cycle [T i ,T i+1 ]; at the same time, the DC submodule calculates the electromagnetic transient simulation step length of the next cycle according to the Thevenin equivalent impedance and equivalent potential of the boundary points of the entire electromechanical transient network;

[0032] The judgment subunit is used to judge whether the system topology has changed. If so, the simulation ends; otherwise, the T i =Ti +△T, update the simulation cycle, and enter the voltage and current fundamental effective value acquisition subunit; wherein △T is the simulation step length.

[0033] Preferably, the hybrid simulation unit further comprises:

[0034] Fault processing subunit, used when the electromagnetic transient calculation network is in T n When a fault occurs at the moment, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process does not start the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until T n+2 time, calculate a cycle period [T n ,T n+2 ] and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, two steps of calculation are performed continuously until T n+1 Moment, from T n+1 From this moment on, the interface timing of the two computing processes is restored to the basic switching timing until the next network topology change or the end of the simulation.

[0035] Preferably, the electromagnetic transient simulation program is ADPSS-ETSDAC.

[0036] The present invention provides an online simulation method and system for an LCC direct current transmission electromechanical electromagnetic hybrid system, which realizes the collaborative simulation calculation of the direct current transmission system model and the rest of the power grid through the electromechanical-electromagnetic transient hybrid simulation technology, solves the problem that the transient characteristics of the direct current transmission equipment cannot be accurately simulated in the electromechanical transient simulation and the electromagnetic transient simulation is difficult to simulate the large-scale alternating and direct current power grid, and also avoids the complexity and limitations of the construction of the simulation example of the alternating and direct current power grid in the general electromechanical transient simulation, forms a general alternating and direct current electromechanical simulation program to call the direct current package model, and improves the accuracy of the electromechanical transient simulation calculation of the alternating and direct current power grid; the present invention proposes an equivalent circuit and interface data exchange timing suitable for the electromechanical transient full network to call the direct current sub-module, based on the basic circuit theory, suitable for various situations such as active and passive networks, realizes the parallel calculation of the electromechanical transient full network and the direct current sub-module under the steady state, ensures the simulation calculation speed when calling the sub-module, and does not reduce the simulation calculation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0038] Figure 1is a flow chart of an online simulation method 100 of an LCC DC transmission machine electric-electromagnetic hybrid system according to an embodiment of the present invention;

[0039] Figure 2 is a schematic diagram of a direct current power transmission system according to an embodiment of the present invention;

[0040] Figure 3 A schematic diagram of a Thevenin equivalent model of a full electromechanical transient network according to an embodiment of the present invention;

[0041] Figure 4 is a schematic diagram of a Norton equivalent model of a DC submodule according to an embodiment of the present invention;

[0042] Figure 5 A diagram showing a data exchange method in a process of calling a DC submodule by an electrical simulation program according to an embodiment of the present invention;

[0043] Figure 6 A schematic diagram of the calling sequence of the DC submodule by the electromechanical transient whole network under normal conditions according to an embodiment of the present invention;

[0044] Figure 7 A schematic diagram of the calling sequence of the DC submodule by the entire electromechanical transient network under fault according to an embodiment of the present invention; and

[0045] Figure 8 Schematic diagram of the structure of an online simulation system 800 of an LCC DC transmission machine electric-electromagnetic hybrid system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0047] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0048] Figure 1 FIG. 1 is a flow chart of an online simulation method 100 of an LCC DC transmission machine electric-electromagnetic hybrid system according to an embodiment of the present invention. Figure 1As shown, the online simulation method of the LCC DC transmission motor electro-electromagnetic hybrid system provided by the present invention in real time realizes the collaborative simulation calculation of the DC transmission system model and the rest of the power grid through the electromechanical-electromagnetic transient hybrid simulation technology, solves the problem that the transient characteristics of the DC transmission equipment cannot be accurately simulated in the electromechanical transient simulation and the electromagnetic transient simulation is difficult to simulate the large-scale AC and DC power grids, and also avoids the complexity and limitations of the construction of AC and DC power grid simulation examples in general electromechanical transient simulation, forming a general AC and DC electromechanical simulation program to call the DC package model function, and improves the accuracy of the electromechanical transient simulation calculation of the AC and DC power grid. The online simulation method 100 of the LCC DC transmission motor electro-electromagnetic hybrid system provided by the embodiment of the present invention starts from step 101. In step 101, the primary system circuit and secondary control system models of the DC transmission system are built based on the electromagnetic transient simulation program, and the two are packaged as a DC sub-module called by the electromechanical transient simulation.

[0049] Preferably, the electromagnetic transient simulation program is ADPSS-ETSDAC.

[0050] In the embodiment of the present invention, the basic component model in ETSDAC is constructed, and the most common bipolar DC transmission system in China is adopted, as shown in the attached Figure 2 As shown. Each pole is composed of two six-pulse converters (twelve-pulse DC) or four six-pulse converters (double twelve-pulse DC). The six-pulse converters of the two poles are connected to the ground through an inductor and a neutral point grounding resistor; at the same time, the two ends of the converter of each pole are connected in series with the smoothing reactor on the other side through a smoothing reactor and a DC transmission line resistor; the commutation bus is connected in parallel with several compensation capacitors and several groups of AC filters. The electromechanical-electromagnetic transient hybrid simulation interface is connected to the commutation bus of the DC transmission system, so that it can be called by the large power grid model in the electromechanical transient.

[0051] The secondary system control protection circuit is built and packaged using the graphical interface of the electromagnetic transient simulation program, and one set is installed at each pole of each station in the DC transmission system. Figure 4The control logic of the secondary control system built. Under normal circumstances, the rectifier side adopts constant current control. The measured current of the DC line on the rectifier side and the current value returned by the low-voltage current limiting module are processed by the adder / subtractor and adjusted by the PI controller to obtain the trigger angle of the converter valve on the rectifier side. This is returned as the input value to the converter in the main circuit of the DC transmission system to control the rectifier side of the DC system main circuit. The inverter side adopts a control mode combining constant current control, constant voltage control and fixed arc extinction angle control. The output value of the low-voltage current limiting module on the inverter side and the measured current of the DC line input to the inverter side are processed by the adder / subtractor, and then the difference is made with the current margin value through the adder / subtractor, and then adjusted by the PI controller to form a constant current control output; the arc extinction angle measurement value, the value output by the current deviation control module and the rated arc extinction angle fixed value are processed by the adder / subtractor, and then adjusted by the PI controller to form a fixed arc extinction angle control output; the inverter side measurement value and the rated voltage fixed value are processed by the adder / subtractor, and then adjusted by the PI controller to form a constant voltage control output. The outputs of constant current control, constant voltage control and fixed arc extinction angle control are finally processed by the minimum value selection module to obtain the trigger angle on the inverter side, which is returned as an input value to the converter in the main circuit of the DC transmission system to control the inverter side of the DC system main circuit.

[0052] The embodiments of the present invention avoid the complexity and limitations of DC transmission system modeling in general hybrid simulation by constructing a DC transmission system model under the ETSDAC full graphical interface without compiling electromagnetic transient simulation code. The encapsulated model is suitable for different AC and DC transmission simulation systems and is not limited to a specific electromechanical network. There is no need to change or re-establish the DC transmission system simulation model, thereby simplifying the simulation process.

[0053] In step 102, the electromechanical transient whole network performs equivalent processing on the DC submodule and the DC submodule performs equivalent processing on the electromechanical transient whole network.

[0054] Preferably, the equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network respectively includes:

[0055] When calculating the internal network of the DC submodule, the Thevenin equivalent is performed on the entire electromechanical transient network to obtain the power frequency equivalent impedance array of the entire electromechanical transient network and the positive, negative, and zero-sequence equivalent potentials of the boundary points to provide them to the DC submodule;

[0056] When calculating the entire electromechanical transient network, the Norton equivalent is performed on the DC submodule to obtain the equivalent admittance matrix of the DC submodule and the positive, negative, and zero-sequence currents and voltages of the boundary points to provide them to the entire electromechanical transient network.

[0057] In the embodiment of the present invention, the electromechanical transient whole network performs equivalent processing on the DC sub-module, and the DC sub-module performs equivalent processing on the electromechanical transient whole network respectively as follows: Figure 3 and Figure 4 As shown in the figure, the equivalent processing method of the electromechanical transient whole network to the DC submodule is shown. Specifically, it includes: (1) when calculating the internal network of the DC submodule, the electromechanical transient whole network is subjected to the Thevenin equivalent, and the power frequency equivalent impedance matrix Z of the electromechanical transient network and the positive, negative, and zero sequence equivalent potential E of the boundary points are generated and provided to the electromagnetic transient network; (2) when calculating the electromechanical transient whole network, the DC submodule is subjected to the Norton equivalent, and the DC submodule calculates the equivalent admittance matrix and the positive, negative, and zero sequence current and voltage of the boundary points.

[0058] In step 103, data exchange between the electromechanical transient full network and the DC submodule is realized through an equivalent circuit. The electromechanical transient full network and the DC submodule call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation.

[0059] Preferably, the data exchange between the electromechanical transient full network and the DC submodule is realized by the equivalent circuit, and the electromechanical transient full network and the DC submodule call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation, including:

[0060] Step 1: The electromechanical transient network obtains the Thevenin equivalent impedance and equivalent potential of the boundary points and transmits them to the DC submodule;

[0061] Step 2: The DC submodule uses the acquired Thevenin equivalent impedance and equivalent potential of the boundary points to calculate the current cycle [T i ,T i+1 ] calculation of the step length of an electromagnetic transient simulation;

[0062] Step 3, calculate the current period [T i ,T i+1 ] at the end time T i+1 When the DC submodule completes the calculation of one electromagnetic transient simulation step, the current cycle [T i ,T i+1 ] is used to calculate the fundamental effective values ​​of the voltage and current at the boundary points based on the calculation results of one cycle, and the fundamental effective values ​​of the voltage and current at the boundary points are sent to the electromechanical transient network for simulation calculation; at the same time, the Davy equivalent impedance and equivalent potential of the electromechanical transient network are obtained again from the simulation calculation process of the electromechanical transient network;

[0063] Step 4: The electromechanical transient network uses the fundamental effective values ​​of the voltage and current at the boundary points to perform the current cycle [T i ,T i+1]; at the same time, the DC submodule calculates the electromagnetic transient simulation step length of the next cycle according to the Thevenin equivalent impedance and equivalent potential of the boundary points of the entire electromechanical transient network;

[0064] Step 5: Determine whether the system topology has changed. If so, the simulation ends. Otherwise, use T i =T i +△T, update the simulation period, and return to step 3; where △T is the simulation step length.

[0065] Preferably, the method further comprises:

[0066] When the electromagnetic transient calculation network is in T n When a fault occurs at the moment, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process does not start the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until T n+2 time, calculate a cycle period [T n ,T n+2 ] and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, two steps of calculation are performed continuously until T n+1 Moment, from T n+1 From this moment on, the interface timing of the two computing processes is restored to the basic switching timing until the next network topology change or the end of the simulation.

[0067] In the implementation mode of the present invention, the electromagnetic transient simulation process at the initial moment of the simulation obtains the power frequency equivalent impedance array Z of the entire electromechanical transient network; Figure 4 It is the data exchange method in the process of the electromechanical simulation program calling the DC submodule. At each call, the electromagnetic transient simulation process of the DC submodule transmits the positive, negative, and zero-sequence current I of the boundary point to the electromechanical transient large power grid simulation process. emt , and the positive, negative, and zero-sequence voltages V emt The electromechanical transient large power grid simulation process transmits the positive, negative and zero-sequence equivalent potentials E of the boundary points to the electromagnetic transient simulation process.

[0068] Figure 6 FIG. 1 is a schematic diagram of the timing of calling the DC submodule by the electromechanical transient whole network under normal circumstances according to an embodiment of the present invention. In an embodiment of the present invention, under normal circumstances, the electromechanical transient whole network and the DC submodule are in accordance with Figure 6 The timing shown in the figure is called to perform electromechanical-electromagnetic transient hybrid simulation. The DC submodule is called in units of electromechanical transient calculation steps. The specific steps include:

[0069] S1, the simulation starts, and the Thevenin equivalent impedance and equivalent potential values ​​of the entire electromechanical transient network at the boundary points are transmitted to the DC submodule.

[0070] S2, the DC submodule uses the Thevenin equivalent impedance and equivalent potential values ​​obtained from the electromechanical transient simulation process to perform custom calculations from T0 to T1, where T0 is the starting time of a calculation time step of the electromechanical transient simulation, and T1 is the ending time of a calculation time step of the electromechanical transient simulation.

[0071] S3, when the DC submodule calculates to time T1, the fundamental effective value of the voltage, current and other parameters at the boundary point is calculated using the calculation result of one cycle in the period [T0, T1], and sent to the whole network electromechanical transient simulation process. At the same time, the Thevenin equivalent impedance and potential of the electromechanical transient network are obtained from the electromechanical transient simulation calculation process.

[0072] S4, after the electromechanical transient calculation process obtains the boundary point information, it performs the network calculation at time T0-T1. At the same time, after the DC submodule calculation process obtains the Thevenin equivalent potential of the electromechanical transient network, it performs the custom calculation for the [T1, T2] period.

[0073] S5, when the DC submodule calculates to time T2, it uses the calculation results of one cycle in the past [T1, T2] period to calculate the fundamental effective value of the voltage, current and other parameters at the boundary point, and sends it to the electromechanical transient calculation process. At the same time, the electromechanical transient calculates the Thevenin equivalent potential of the entire electromechanical transient network at the boundary point and sends it to the DC submodule calculation process.

[0074] By changing the T value, T=T+ΔT (T is the calculation time, Δt is the calculation step), the above calls are repeated until the system topology changes or the simulation ends.

[0075] Figure 7 FIG. 1 is a schematic diagram of the timing of calling the DC submodule by the entire electromechanical transient network under a fault according to an embodiment of the present invention. Figure 7As shown in the figure, it is the processing method of calling the timing when the system fails. For example, suppose that at time T4, the electromagnetic transient calculation network fails. At this time, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process has not started the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until time T6. At this time, the effective value of the fundamental wave of the boundary point of the cycle period T4-T6 is calculated and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, it then continuously performs two step-length calculations until time T5. Starting from time T5, the interface timing of the two calculation processes is restored to the basic exchange timing until the next network topology change or the end of the simulation.

[0076] The implementation mode of the present invention proposes an exchange timing of equivalent circuits and interface data suitable for the electromechanical transient full network to call the DC sub-module. It is based on basic circuit theory and is applicable to various situations such as active and passive networks. It realizes parallel calculation of the electromechanical transient full network and the DC sub-module under steady-state conditions, ensures the simulation calculation speed when calling the sub-module, and does not reduce the simulation calculation accuracy.

[0077] Figure 8 FIG. 8 is a schematic diagram of the structure of an online simulation system 800 of an LCC DC transmission motor electric-electromagnetic hybrid system according to an embodiment of the present invention. Figure 8 As shown, the online simulation system 800 of the LCC DC transmission motor electric-electromagnetic hybrid system provided by the embodiment of the present invention includes: a simulation model establishment unit 801, an equivalent processing unit 802 and a hybrid simulation unit 803.

[0078] Preferably, the simulation model building unit 801 is used to build the primary system circuit and secondary control system models of the DC power transmission system based on the electromagnetic transient simulation program, and encapsulate the two into a DC sub-module called by the electromechanical transient simulation.

[0079] Preferably, the electromagnetic transient simulation program is ADPSS-ETSDAC.

[0080] Preferably, the equivalent processing unit 802 is used to perform equivalent processing of the electromechanical transient full network on the DC sub-module and the DC sub-module on the electromechanical transient full network respectively.

[0081] Preferably, the equivalent processing unit 802 performs equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network, respectively, including:

[0082] When calculating the internal network of the DC submodule, the Thevenin equivalent is performed on the entire electromechanical transient network to obtain the power frequency equivalent impedance array of the entire electromechanical transient network and the positive, negative, and zero-sequence equivalent potentials of the boundary points to provide them to the DC submodule;

[0083] When calculating the entire electromechanical transient network, the Norton equivalent is performed on the DC submodule to obtain the equivalent admittance matrix of the DC submodule and the positive, negative, and zero-sequence currents and voltages of the boundary points to provide them to the entire electromechanical transient network.

[0084] Preferably, the hybrid simulation unit 803 is used to realize data exchange between the electromechanical transient full network and the DC sub-module through an equivalent circuit. The electromechanical transient full network and the DC sub-module call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation.

[0085] Preferably, the hybrid simulation unit realizes data exchange between the electromechanical transient full network and the DC submodule through an equivalent circuit, and the electromechanical transient full network and the DC submodule call each other according to a preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation, including:

[0086] Thevenin equivalent impedance and potential acquisition subunit, used to enable the electromechanical transient whole network to acquire the Thevenin equivalent impedance and equivalent potential of the boundary points and pass them to the DC submodule;

[0087] The electromagnetic transient simulation calculation subunit is used to enable the DC submodule to use the acquired Thevenin equivalent impedance and equivalent potential of the boundary points to perform the current cycle [T i ,T i+1 ] calculation of the step length of an electromagnetic transient simulation;

[0088] The voltage and current fundamental effective value acquisition subunit is used to calculate the current cycle [T i ,T i+1 ] at the end time T i+1 When the DC submodule completes the calculation of one electromagnetic transient simulation step, the current cycle [T i ,T i+1 ] is used to calculate the fundamental effective values ​​of the voltage and current at the boundary points based on the calculation results of one cycle, and the fundamental effective values ​​of the voltage and current at the boundary points are sent to the electromechanical transient network for simulation calculation; at the same time, the Davy equivalent impedance and equivalent potential of the electromechanical transient network are obtained again from the simulation calculation process of the electromechanical transient network;

[0089] The electromechanical transient simulation subunit is used to make the electromechanical transient network use the fundamental effective values ​​of the voltage and current at the boundary points to perform the current cycle [T i ,T i+1]; at the same time, the DC submodule calculates the electromagnetic transient simulation step length of the next cycle according to the Thevenin equivalent impedance and equivalent potential of the boundary points of the entire electromechanical transient network;

[0090] The judgment subunit is used to judge whether the system topology has changed. If so, the simulation ends; otherwise, the T i =T i +△T, update the simulation cycle, and enter the voltage and current fundamental effective value acquisition subunit; wherein △T is the simulation step length.

[0091] Preferably, the hybrid simulation unit further comprises: a fault processing subunit for n When a fault occurs at the moment, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process does not start the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until T n+2 time, calculate a cycle period [T n ,T n+2 ] and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, two steps of calculation are performed continuously until T n+1 Moment, from T n+1 From this moment on, the interface timing of the two computing processes is restored to the basic switching timing until the next network topology change or the end of the simulation.

[0092] The online simulation system 800 of the LCC DC transmission motor electric-electromagnetic hybrid system of the embodiment of the present invention corresponds to the online simulation method 100 of the LCC DC transmission motor electric-electromagnetic hybrid system of another embodiment of the present invention, and will not be described in detail here.

[0093] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0094] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / said / the [means, components, etc.]" are to be openly interpreted as at least one instance of the means, components, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily have to be performed in the exact order disclosed, unless explicitly stated otherwise.

[0095] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0096] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0097] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0098] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An online simulation method for an LCC DC transmission motor electro-electromagnetic hybrid system, characterized in that: The method comprises: Based on the electromagnetic transient simulation program, the primary system circuit and secondary control system models of the DC transmission system are built, and the two are encapsulated as DC sub-modules called by electromechanical transient simulation; The equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network are respectively performed; The data exchange between the electromechanical transient full network and the DC submodule is realized through the equivalent circuit. The electromechanical transient full network and the DC submodule call each other according to the preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation, including: Step 1: The electromechanical transient network obtains the Thevenin equivalent impedance and equivalent potential of the boundary points and transmits them to the DC submodule; Step 2: The DC submodule uses the acquired Thevenin equivalent impedance and equivalent potential of the boundary points to calculate the current cycle [T i ,T i+1 ] calculation of the step length of an electromagnetic transient simulation; Step 3, calculate the current period [T i ,T i+1 ] at the end time T i+1 When the DC submodule completes the calculation of one electromagnetic transient simulation step, the current cycle [T i ,T i+1 ] is used to calculate the fundamental effective values ​​of the voltage and current at the boundary points based on the calculation results of one cycle, and the fundamental effective values ​​of the voltage and current at the boundary points are sent to the electromechanical transient network for simulation calculation; at the same time, the Davy equivalent impedance and equivalent potential of the electromechanical transient network are obtained again from the simulation calculation process of the electromechanical transient network; Step 4: The electromechanical transient network uses the fundamental effective values ​​of the voltage and current at the boundary points to perform the current cycle [T i ,T i+1 ]; at the same time, the DC submodule calculates the electromagnetic transient simulation step length of the next cycle according to the Thevenin equivalent impedance and equivalent potential of the boundary points of the entire electromechanical transient network; Step 5: Determine whether the system topology has changed. If so, the simulation ends. Otherwise, use T i =T i +△T, update the simulation period, and return to step 3; where △T is the simulation step length.

2. The method according to claim 1, characterized in that The equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network respectively includes: When calculating the internal network of the DC submodule, the Thevenin equivalent is performed on the entire electromechanical transient network to obtain the power frequency equivalent impedance array of the entire electromechanical transient network and the positive, negative, and zero-sequence equivalent potentials of the boundary points to provide them to the DC submodule; When calculating the entire electromechanical transient network, the Norton equivalent is performed on the DC submodule to obtain the equivalent admittance matrix of the DC submodule and the positive, negative, and zero-sequence currents and voltages of the boundary points to provide them to the entire electromechanical transient network.

3. The method according to claim 1, characterized in that The method further comprises: When the electromagnetic transient calculation network is in T n When a fault occurs at the moment, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process does not start the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until T n+2 time, calculate a cycle period [T n ,T n+2 ] and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, two steps of calculation are performed continuously until T n+1 Moment, from T n+1 From this moment on, the interface timing of the two computing processes is restored to the basic switching timing until the next network topology change or the end of the simulation.

4. The method according to claim 1, characterized in that: The electromagnetic transient simulation program is ADPSS-ETSDAC.

5. An online simulation system for an LCC DC transmission motor-electromagnetic hybrid system, characterized in that: The system comprises: A simulation model building unit is used to build a primary system circuit and a secondary control system model of a DC power transmission system based on an electromagnetic transient simulation program, and encapsulate the two into a DC submodule called by an electromechanical transient simulation; An equivalent processing unit, used for respectively performing equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network; The hybrid simulation unit is used to realize data exchange between the electromechanical transient full network and the DC submodule through equivalent circuits. The electromechanical transient full network and the DC submodule call each other according to the preset calling sequence to perform electromechanical-electromagnetic transient hybrid simulation, including: Thevenin equivalent impedance and potential acquisition subunit, used to enable the electromechanical transient whole network to acquire the Thevenin equivalent impedance and equivalent potential of the boundary points and pass them to the DC submodule; The electromagnetic transient simulation calculation subunit is used to enable the DC submodule to use the acquired Thevenin equivalent impedance and equivalent potential of the boundary points to perform the current cycle [T i ,T i+1 ] calculation of the step length of an electromagnetic transient simulation; The voltage and current fundamental effective value acquisition subunit is used to calculate the current cycle [T i ,T i+1 ] at the end time T i+1 When the DC submodule completes the calculation of one electromagnetic transient simulation step, the current cycle [T i ,T i+1 ] is used to calculate the fundamental effective values ​​of the voltage and current at the boundary points based on the calculation results of one cycle, and the fundamental effective values ​​of the voltage and current at the boundary points are sent to the electromechanical transient network for simulation calculation; at the same time, the Davy equivalent impedance and equivalent potential of the electromechanical transient network are obtained again from the simulation calculation process of the electromechanical transient network; The electromechanical transient simulation subunit is used to make the electromechanical transient network use the fundamental effective values ​​of the voltage and current at the boundary points to perform the current cycle [T i ,T i+1 ]; at the same time, the DC submodule calculates the electromagnetic transient simulation step length of the next cycle according to the Thevenin equivalent impedance and equivalent potential of the boundary points of the entire electromechanical transient network; The judgment subunit is used to judge whether the system topology has changed. If so, the simulation ends; otherwise, the T i =T i +△T, update the simulation cycle, and enter the voltage and current fundamental effective value acquisition subunit; wherein △T is the simulation step length.

6. The system according to claim 5, characterized in that The equivalent processing unit performs equivalent processing of the electromechanical transient whole network to the DC submodule and the DC submodule to the electromechanical transient whole network, respectively, including: When calculating the internal network of the DC submodule, the Thevenin equivalent is performed on the entire electromechanical transient network to obtain the power frequency equivalent impedance array of the entire electromechanical transient network and the positive, negative, and zero-sequence equivalent potentials of the boundary points to provide them to the DC submodule; When calculating the entire electromechanical transient network, the Norton equivalent is performed on the DC submodule to obtain the equivalent admittance matrix of the DC submodule and the positive, negative, and zero-sequence currents and voltages of the boundary points to provide them to the entire electromechanical transient network.

7. The system according to claim 5, characterized in that The hybrid simulation unit further comprises: Fault processing subunit, used when the electromagnetic transient calculation network is in T n When a fault occurs at the moment, the electromagnetic transient calculation process of the DC submodule or the electromechanical transient full network calculation process does not start the calculation after the fault. The electromechanical transient full network calculation process sends the interface information to the electromagnetic transient calculation process of the DC submodule as usual. After the electromagnetic transient calculation process of the DC submodule obtains the information, it performs a cycle calculation until T n+2 time, calculate a cycle period [T n ,T n+2 ] and sent to the electromechanical transient calculation process. After the electromechanical transient obtains the equivalent circuit parameters of the electromagnetic transient network, two steps of calculation are performed continuously until T n+1 Moment, from T n+1 From this moment on, the interface timing of the two computing processes is restored to the basic switching timing until the next network topology change or the end of the simulation.

8. The system according to claim 5, characterized in that The electromagnetic transient simulation program is ADPSS-ETSDAC.

Images