CN108628182A - A kind of small step-length emulation mode of electro-magnetic transient and system - Google Patents

Abstract

The invention relates to an electromagnetic transient small-step simulation method and system, which cooperates with a large-step system on an external server side to carry out parallel simulation calculations for grid sub-networks. The large-step system completes the decoupling of grid sub-networks. Transient simulation operation and return the simulation results to the large-step system through data interaction, so as to achieve the purpose of real-time simulation of the entire power grid and grasp the dynamic process of power grid operation. The present invention uses FPGA as a simulation platform, utilizes the characteristics of low FPGA cost, highly parallelized computing units, and is suitable for highly streamlined operations. Simultaneously, parallel simulation calculations are performed on different power grid components, and the overall system is highly streamlined, ensuring simulation The operating frequency and throughput of the system are improved without compromising the accuracy.

Description

An electromagnetic transient small-step simulation method and system

technical field

The invention relates to a method and system for performing electromagnetic transient small-step simulation in power grid simulation, in particular to an electromagnetic transient small-step simulation method and system.

Background technique

Power grid simulation is divided into offline simulation and real-time simulation. The electromagnetic transient simulation program (Electro-MagneticTransient Program, EMTP) has been widely used in the offline simulation of the power grid, and the offline simulation software is generally installed on a server or workstation with strong computing power, and its simulation step size is on the order of 100us. The real-time simulation can grasp the actual working state of the power grid more quickly and accurately, which is of great significance to the safety assessment and troubleshooting of the power grid.

At the same time, power grid simulation can also be divided into electromechanical transient simulation and electromagnetic transient simulation. The electromechanical transient process refers to the process of changing the mechanical motion of the motor rotor caused by the change of the electromagnetic torque. Electromechanical transient simulation is generally applied to issues such as power angle stability, frequency stability, voltage stability, and short-circuit calculation. The simulation scale is generally large, and the simulation step size is generally at the millisecond level. Since the step size of the electromechanical transient simulation is very large, the simulation software can also meet the real-time requirements of the electromechanical transient simulation. The electromagnetic transient process refers to the process of voltage and current changes caused by the interaction of electric field energy and magnetic field energy. Electromagnetic transient simulation is generally applied to operation transients, fault transients or other fast dynamic responses. The simulation scale is generally small, and the simulation step size is generally at the microsecond level.

Due to the emergence of various high-frequency devices, the real-time simulation step size of the power grid needs to be reduced from the original 50us-100us to 1us-5us, and the simulation calculation burden has increased significantly. Due to the sharp decrease of the simulation step size, the existing offline simulation software package has been unable to meet the real-time requirements of power grid simulation. To complete the real-time simulation of the power grid, it not only needs to be carried out on the software level, but also requires the cooperation of hardware devices to achieve the required simulation speed.

At present, real-time simulation devices for power grids include the real-time digital simulator RTDS based on parallel processors, the RT-LAB real-time simulation device using computer clusters as the simulation platform, and the full digital simulation system ARENE based on workstations. However, the above simulation systems all have their own shortcomings, such as high cost and limited simulation scale.

Due to various difficulties in real-time simulation of electromagnetic transients, traditional general-purpose processor systems cannot meet the needs of real-time simulation under the background of the expansion of power grid simulation scale and higher real-time requirements.

Contents of the invention

In order to solve the deficiencies in the above-mentioned prior art, the object of the present invention is to provide a method and system for electromagnetic transient small-step simulation. The present invention cooperates with the large-step system on the external server side to perform parallel simulation calculations on the power grid. The step size system completes the decoupling of the power grid sub-network. This system completes the electromagnetic transient simulation calculation and returns the simulation results to the large step size system through data interaction, so as to achieve real-time simulation of the entire power grid and grasp the dynamic process of power grid operation. . The invention ensures the accuracy, scale and configurability of the simulation system at low cost.

The object of the present invention is to adopt following technical scheme to realize:

The present invention provides a kind of electromagnetic transient small-step simulation method, and its improvement is that, described method comprises the following steps:

Solve the node voltage vector V _s by the matrix multiplication of the conductance inverse matrix G ₂ ^-1 and the node current vector I _his in the large-step simulation system;

If the total simulation time t of the FPGA platform < the maximum simulation time tfinal, then the total simulation time t plus the simulation time dt of a small step size, t=t+dt; complete the calculation update equivalent in the component area of the large step size simulation system Work on the historical current value, and accumulate the current injection value of the calculation node in the component area, and periodically interact with the large-step simulation system for data; until t>=tfinal, the simulation ends and the simulation result is output.

Further, before solving V _s through the matrix multiplication of G ₂ ^-1 and I _his in the large-step simulation system, it also includes:

The electromagnetic transient small step size simulation system of the FPGA platform receives initialization data from the large step size simulation system, and writes the initialization data into the internal data area of the FPGA platform; sets the total simulation time t of the small step size.

Further, the large-step simulation system refers to a large-step simulation system based on an external server, and the large-step simulation system is used for the decoupling of the power grid, and provides simulation for the electromagnetic transient small-step simulation system Required initialization data and interaction data.

Further, the initialization data includes the electromagnetic transient small-step system network conductance matrix and its inverse matrix, component configuration information, constants and components required for electromagnetic transient small-step simulation;

The components include conventional components SLA of capacitance, inductance and resistance, single-phase winding transformer component STB, single-phase AC independent current source SCI, single-phase AC independent voltage source SCV, controlled current source CIS, controlled voltage source CVS, switching element BRK and transmission line LC.

Further, after solving the node voltage vector V _s , it also includes:

Determine whether to update G ₂ ^-1 according to whether the switch inside the FPGA platform is activated;

If the switch operates, update G ₂ ^-1 according to the latest switch state and refresh the corresponding address table information, and solve V _s through the matrix multiplication of the updated G ₂ ^-1 and I _his ; if the switch does not operate, G will not be updated _2-1 ^.

Further, the formula for solving the node voltage vector V _s is as follows:

G ₂ ⁻¹ I _his =V _s (1).

Further, before the judgment of whether the switch inside the FPGA platform acts, it also includes: the switch action state is sent to the electromagnetic transient small-step simulation system by the large-step system through periodic data interaction;

If a new conductance matrix is selected, the node voltage vector is obtained by matrix multiplication of the new conductance matrix and the node current vector; otherwise, V _s is directly obtained by the matrix multiplication of G ₂ ^-1 and I _his .

Further, the periodic data interaction with the large-step-size simulation system includes: setting the simulation step size of the electromagnetic transient small-step-size system as T ₁ , and the simulation step size of the large-step-size simulation system as T ₂ , N is a positive integer, then the number of small step iterations KLOOP=N·T ₂ /T ₁ performs data interaction of the large and small step simulation system;

Each large-step-size simulation system interacts with the large-step-size simulation system to send simulation real-time excitation signals, new simulation data, and node numbers required for large-step-size simulation system simulation, and the electromagnetic transient small-step-size simulation system will simulate large-step The data sent by the system is written into the bus, and the new data is used for the simulation operation starting from the next small step; at the same time, the electromagnetic transient small step simulation system uses the node number sent by the large step simulation system in each interaction returning the simulation data of the corresponding node to the large-step simulation system; the simulation data sent by the large-step simulation system includes: new parameters of component simulation and switch action states.

The present invention also provides an electromagnetic transient small-step simulation system based on an FPGA platform. The improvement is that the system includes a component area, a core calculation area, a public storage module, a large and small step size interface module, and a top-level control module; Among them, the component area includes a calculation module for completing the calculation inside a single component, a control module for controlling the data flow and calculation timing of a single component during calculation, and a node current accumulation module for accumulating node current injection values; the core The calculation area is used to solve the node voltage vector; the public storage module is used for the storage of simulation data; the size step size interface module is used for data interaction between the large step size simulation system and the electromagnetic transient small step size simulation system; the The top-level control module is used to generate the overall sequential logic and excitation signals.

Further, the components used in the component area include conventional components SLA of capacitors, inductors and resistors, single-phase winding transformer components STB, single-phase AC independent current source SCI, single-phase AC independent voltage source SCV, controlled current source CIS, controlled voltage source CVS, switching element BRK and transmission line LC.

Compared with the closest prior art, the excellent effect that the technical solution provided by the present invention has is:

The present invention uses FPGA as a simulation platform, and utilizes the characteristics of FPGA with low cost, highly parallelized computing units, and suitable for highly pipelined operations. In contrast, FPGA has highly parallelized computing logic units, which are suitable for highly pipelined operations. Extremely flexible and configurable, it is ideal for hardware acceleration of electromagnetic transient simulations without sacrificing communication latency and simulation accuracy. At the same time, different power grid components are simulated and calculated in parallel, and the overall system is highly streamlined, which improves the operating frequency and throughput of the system while ensuring the simulation accuracy.

The electromagnetic transient small-step simulation system based on the FPGA platform provided by the invention has low cost; the simulation scale is relatively large, and double-precision floating-point numbers are used as the basic data format to ensure simulation accuracy. In the case of ensuring the accuracy, the simulation step size of the microsecond level is achieved, thereby meeting the real-time requirements of the electromagnetic transient simulation, and has certain flexibility and configurability. It can cooperate with the large-step simulation system on the server side to carry out real-time sub-network parallel simulation of the power grid.

Description of drawings

Fig. 1 is the simulation flow diagram of electromagnetic transient small-step simulation system provided by the present invention;

Fig. 2 is the structural representation of the electromagnetic transient small-step simulation system provided by the present invention;

Fig. 3 is a timing diagram of the electromagnetic transient small-step simulation system provided by the present invention.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

The following description and drawings illustrate specific embodiments of the invention sufficiently to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. The examples merely represent possible variations. Individual components and functions are optional unless explicitly required, and the order of operations may vary. Portions and features of some embodiments may be included in or substituted for those of other embodiments. The scope of embodiments of the present invention includes the full scope of the claims, and all available equivalents of the claims. These embodiments of the present invention may be referred to herein, individually or collectively, by the term "invention", which is for convenience only and is not intended to automatically limit the application if in fact more than one invention is disclosed The scope is any individual invention or inventive concept.

Embodiment one

The solution adopted by the present invention to solve the technical problem is: an electromagnetic transient simulation method based on an FPGA platform with a small step size, and hardware acceleration is performed for the electromagnetic transient simulation that the simulation software cannot meet the real-time requirement. The step size of the electromagnetic transient simulation is on the order of microseconds, and the simulation software cannot meet the real-time requirement, so it is completed on the small step size system of the present invention. The topology of the power grid, component parameter information, conductance matrix and its inverse matrix, and constant parameters required for simulation are formed from the large-step system, and the small-step system is initialized through data interaction. Afterwards, the small step size system independently performs parallel simulation iterative operations on each component, and solves the node current vector and node voltage vector. The system uses double-precision floating-point numbers as the basic data format to ensure the simulation accuracy in the iterative process. Assume that the simulation step size of the small step size system is T1, the simulation step size of the large step size system is T2, and N is a positive integer, then when the number of small step size iterations KLOOP=N·T2/T1, carry out a large step size simulation system Data interaction, so as to complete the parallel simulation operation of the sub-network of the power grid.

The invention utilizes the characteristics of the FPGA simulation platform to perform electromagnetic transient simulation calculations with fixed system frequency and simulation step size, independently and parallel simulation calculations for different components in the power grid, and periodically returns the simulation results to the big step long system. In order to realize the simulation system, as shown in Figure 1, the present invention adopts the following methods and steps:

Step 1: Receive initialization data from the large-step simulation system, and the electromagnetic transient small-step simulation system of the FPGA platform writes and initializes the interactive data.

Step 2, set the total simulation time t=0, and start the simulation.

Step 3, solve the node voltage vector V _s through the matrix multiplication of the conductance inverse matrix G ₂ ^-1 and the node current vector I _his ;

Step 4, judging whether to select a new conductance matrix according to the switch action state, and completing the corresponding configuration.

Step 5, solve the node voltage vector through the matrix multiplication of the conductance inverse matrix and the node current vector.

Step 6. Determine whether the total simulation time t is greater than the set maximum simulation time tfinal. If the total simulation time t has reached the maximum simulation time tfinal, then output the final simulation result and stop the simulation system; otherwise, go to step 7.

Step 7, the total simulation time t plus the simulation time dt of a small step, t=t+dt.

In step 8, the work of calculating and updating the equivalent historical current source is completed independently and in parallel in each component area, and the node current injection values at both ends of each component are accumulated.

In step 9, the node current injection values of different components on each node are accumulated, and then return to step 4 for the next simulation iterative operation, and periodically interact with the large-step simulation system for data.

In said step 1, the large-step simulation system refers to a large-step simulation system based on an external server, which needs to be responsible for the decoupling of the grid sub-network and provide the electromagnetic transient small-step simulation system with the required simulation information. Initialization data and interaction data.

In the step 1, the initialization data includes the conductance matrix of the small-step system network and its inverse matrix, component configuration information, constants and component variables required for electromagnetic transient small-step simulation. Among them, the description of the circuit topology mainly comes from the node numbers at both ends of different components. Taking nmax as the maximum number of nodes supported by the electromagnetic transient small-step simulation system, the grid nodes are numbered from 1 to nmax, and the number of nodes at both ends of the components is The position of the element in the grid can be determined.

In said step 3, the formula for solving the node voltage vector V _s is as follows:

G ₂ ^-1 I _his = V _s (1)

Among them: G ₂ ^-1 is the conductance inverse matrix; I _his is the node current vector; V _s is the node voltage vector.

In step 4, the switching action state is sent from the large-step system to the small-step simulation system through periodic data interaction.

In the step 8, the calculation of the equivalent historical current source of each component area is completed according to the EMTP algorithm, and for the components whose current accumulation takes a long time, the method of parallel calculation of multiple current accumulation modules is used to improve the overall timing of the system. And the arithmetic units used in the calculation of the component area are all generated using the IP that comes with the FPGA design kit.

In said step 9, set the simulation step size of the small step size system as T1, the simulation step size of the large step size system as T2, and N is a positive integer, then carry out when the number of small step size iterations KLOOP=N T2/T1 Data interaction of a large and small step size simulation system. Each interaction between large and small step simulation systems needs to send simulation real-time excitation signals, new simulation data, and node numbers required for large step simulation system simulation by the large step simulation system, and the small step simulation system will send the large step simulation system The sent data is written into the bus, and the new data is used for the next simulation operation with a small step size; at the same time, the small step size simulation system will send the corresponding node number according to the node number sent by the large step size simulation system in this interaction. The simulation data is returned to the large-step simulation system. The simulation data sent by the large-step simulation system includes: new parameters of component simulation, switch action status, etc.

Embodiment two

Based on the same inventive concept, the present invention also provides an electromagnetic transient small-step simulation system based on FPGA platform. The system structure is shown in Fig. Step size interface module and top-level control module. Among them, the component area includes the calculation module, control module and node current accumulation module; the core calculation area is responsible for matrix operation; the public storage module is responsible for the storage of simulation data; the large and small step interface module is responsible for the large step simulation system and the electromagnetic transient small step The data interaction of the simulation system; the top-level control module is responsible for the overall timing logic and the generation of excitation signals. The large-step-size simulation system on the external server side performs data interaction with the small-step-size simulation system of electromagnetic transient state through the large-scale step-size interface module.

The components included in the simulation system are: capacitors, inductors, resistors and other conventional components SLA, unidirectional winding transformer components STB, single-phase AC independent current source SCI, single-phase AC independent voltage source SCV, ideal current source CIS, ideal voltage source CVS , switching element BRK etc. The system uses double-precision floating-point numbers as the basic data format.

Embodiment three

Take a complete simulation process as an implementation example of this system. It is advisable to set the large step size as 50us and the small step size as 2us. The overall timing is shown in Figure 3.

Step 1: Receive initialization data from the large-step simulation system, and the electromagnetic transient small-step simulation system of the FPGA platform writes and initializes the interactive data. The initialization data includes: network conductance matrix and its inverse matrix, component configuration information, constants and component variables required for electromagnetic transient small-step simulation.

Step 2, set the total simulation time t=0, and start the simulation.

Step 3, solve the node voltage vector V _s through the matrix multiplication of the conductance inverse matrix G ₂ ^-1 and the node current vector I _his . This operation is done by the core computing area.

Step 4, judging whether to select a new conductance matrix according to the switch action state, and completing the corresponding configuration. The state change of switch action is sent from the large-step simulation system to the small-step simulation system in the form of data interaction.

Step 5, solve the node voltage vector through the matrix multiplication of the conductance inverse matrix and the node current vector. This operation is done by the core computing area.

Step 6, judge whether the total simulation time t is greater than the set maximum simulation time tfinal, if t has reached tfinal, then output the final simulation result, and stop the simulation system; otherwise, go to step 7.

Step 7, the total simulation time plus the simulation time dt of a small step size, t=t+dt. According to the previous assumption, dt=2us.

In step 8, the work of calculating and updating the equivalent historical current source is completed independently and in parallel in each component area, and the node current injection values at both ends of each component are accumulated. For components whose accumulation time of the node current injection value is too long, the time sequence is optimized by using multiple accumulation modules to calculate in parallel.

In step 9, the node current injection values of different components on each node are accumulated. Then go back to step 4, carry out the next simulation iterative operation, and periodically interact with the large-step simulation system for data. According to the previous assumption, data interaction is performed every 50/2=25 iterations. During the interactive process, the electromagnetic transient small-step simulation system receives new simulation data and returns corresponding simulation data according to the requirements of the large-step simulation system.

The present invention uses FPGA as a simulation platform, utilizes the characteristics of low FPGA cost, highly parallelized computing units, and is suitable for highly streamlined operations. Simultaneously, parallel simulation calculations are performed on different power grid components, and the overall system is highly streamlined, ensuring simulation The operating frequency and throughput of the system are improved without compromising the accuracy.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific embodiments of the present invention. , any modifications or equivalent replacements that do not deviate from the spirit and scope of the present invention are within the protection scope of the claims of the present invention pending application.

Claims (10)

1. a kind of small step-length emulation mode of electro-magnetic transient, which is characterized in that the method includes following step：

Pass through conductance inverse matrix G in big step-length analogue system₂ ^-1With node current vector I_hisMatrix multiplication solution node voltage Vectorial V_s；

If total simulation time t ＜ maximum simulation times tfinal of FPGA platform, total simulation time t are plus one small step of emulation Long time dt, t=t+dt；It completes to calculate the work for updating equivalent historical current value in the element region of big step-length analogue system, And add up to the calculate node electric current injection value of element region, periodically data interaction is carried out with big step-length analogue system； Until t>=tfinal then emulates end and exports simulation result.

2. the small step-length emulation mode of electro-magnetic transient as described in claim 1, which is characterized in that passing through big step-length analogue system In G₂ ^-1And I_hisMatrix multiplication solve V_sBefore, further include：

The small step-length analogue system of electro-magnetic transient of FPGA platform receives initialization data from big step-length analogue system, and will initialization The internal data field of FPGA platform is written in data；The total simulation time t of small step-length is set.

3. the small step-length emulation mode of electro-magnetic transient as claimed in claim 2, which is characterized in that the big step-length analogue system is Referring to the big step-length analogue system based on external server end, subnetting of the big step-length analogue system for power grid decouples, and The initialization data and interaction data needed for emulation are provided for the small step-length analogue system of electro-magnetic transient.

4. the small step-length emulation mode of electro-magnetic transient as claimed in claim 2 or claim 3, which is characterized in that the initialization package Include the small step-length grid conductance matrix of electro-magnetic transient and its inverse matrix, elements configuration information, electro-magnetic transient small step-length emulation institute The constant and element needed；

The element includes the customary components SLA of capacitance, inductance, resistance, single-phase winding transformer element STB, and single phase ac is only Vertical current source SCI, single phase ac independent voltage source SCV, controlled current source CIS, controlled voltage source CVS, switch element BRK and biography Defeated line LC.

5. the small step-length emulation mode of electro-magnetic transient as described in claim 1, which is characterized in that in solution node voltage vector V_s Later, further include：

Decide whether to update G according to whether the switch inside FPGA platform acts₂ ^-1；

If switch motion, G is updated according to newest on off state₂ ^-1And refresh corresponding address table information, by updated G₂ ^-1And I_hisMatrix multiplication solve V_s；If switch is failure to actuate, G is not updated₂ ^-1。

6. the small step-length emulation mode of electro-magnetic transient as claimed in claim 5, which is characterized in that solution node voltage vector V_s's Formula is as follows：

G₂ ^-1I_his=V_s (1)。

7. the small step-length emulation mode of electro-magnetic transient as claimed in claim 5, which is characterized in that in the judgement FPGA platform Before whether the switch in portion acts, further include：Switch motion state passes through periodic data interactive mode by big step-length system It is sent in the small step-length analogue system of electro-magnetic transient.

8. the small step-length emulation mode of electro-magnetic transient as described in claim 1, which is characterized in that it is described periodically with big step-length Analogue system carries out data interaction, including：If the simulation step length of the small step-length system of electro-magnetic transient is T₁, big step-length analogue system Simulation step length is T₂, N is positive integer, then small step-length iterations KLOOP=NT₂/T₁Size step-length emulation system of Shi Jinhang The data interaction of system；

Each size step-length analogue system interaction is sent by big step-length analogue system emulates real-time pumping signal, new emulation data And the node serial number needed for big step-length analogue system emulation, the small step-length analogue system of electro-magnetic transient send out big step-length analogue system The data write bus sent, and new data are used for the simulation calculating that small step-length starts next time；Meanwhile electro-magnetic transient small step The node serial number that long analogue system is sent in each interaction according to big step-length analogue system returns the emulation data of respective nodes Return big step-length analogue system；The emulation data that the big step-length analogue system is sent include：The new parameter and open that element emulates Close action state.

9. a kind of small step-length analogue system of electro-magnetic transient based on FPGA platform, which is characterized in that the system comprises element region, Core calculations area, common memory means, size step-length interface module and top layer control module；Wherein, element region includes being used for Complete the computing module of the calculating inside discrete component, for controlling data flow when discrete component calculates and calculating the control of sequential Molding block and node current accumulator module for summing node electric current injection value；The core calculations area is for solution node electricity The amount of pressing to；The common memory means are used to emulate the storage of data；The size step-length interface module is emulated for big step-length The data interaction of system and the small step-length analogue system of electro-magnetic transient；The top layer control module for generate whole sequential logic and Pumping signal.

10. the small step-length analogue system of electro-magnetic transient as claimed in claim 9, which is characterized in that the element region applied to Element includes the customary components SLA of capacitance, inductance, resistance, single-phase winding transformer element STB, single phase ac independent current SCI, single phase ac independent voltage source SCV, controlled current source CIS, controlled voltage source CVS, switch element BRK and transmission line LC.