Static synchronous phase modifier inertia evaluation method and system

Abstract

The invention discloses a static synchronous phase modifier inertia evaluation method and system, and the method comprises the steps: firstly, data collection: collecting the output power, system frequency, virtual synchronous phase and control parameters of a static synchronous phase modifier in real time; secondly, for frequency response analysis, applying power disturbance to the system, and calculating frequency deviation, frequency change rate and inertia response power based on acquired data; and finally, for inertia evaluation, calculating an inertia evaluation index based on the dynamic response data, and quantitatively evaluating the inertia supporting capability of the static synchronous phase modifier. On one hand, evaluation indexes are extracted based on a power electronic equipment virtual inertia control model, and the defect that a traditional inertia evaluation model is only suitable for mechanical rotational inertia of a synchronous generator is overcome; and on the other hand, distribution characteristics of system frequency and inertia caused by access of a large amount of power electronic equipment are considered, so that the inertia evaluation model is more accurate, and the supporting capability of the static synchronous phase modifier to the system after system disturbance can be accurately described.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of synchronous condenser inertia evaluation, and particularly relates to a static synchronous condenser inertia evaluation method and system. BACKGROUND

[0002] With the deepening of the "double carbon" target and the rapid construction of new power systems, the proportion of power electronic equipment in the power system is getting larger and larger, which squeezes the power generation space of traditional thermal power rotating equipment, and further leads to insufficient inertia of new energy power systems, which reduces the anti-interference ability of the power system. At the same time, the power electronic equipment dominated by the converter consumes a large amount of reactive power when it is in normal operation. In order to ensure voltage stability, the power system is equipped with synchronous condensers and other reactive power compensation equipment. On the one hand, it has inertia support capability, and on the other hand, it can provide fast reactive power support through delayed phase and advanced phase operation, which is a strong support for stable operation of new energy power systems.

[0003] However, the traditional condenser is a rotating device, which has high maintenance cost and frequent shutdown for maintenance, and has obvious disadvantages. Therefore, the static synchronous condenser based on power electronic components emerges as the times require. It uses the most advanced network control technology and super capacitor short-time energy storage technology to form active support for the power grid, and has inertia support capability like synchronous machines through virtual synchronous technology. However, there is still a lack of research on the evaluation of the inertia support capability of static synchronous condensers.

[0004] Traditional inertia evaluation methods mainly include two types. One is based on inertia constant, which is mainly suitable for rotating devices with rotors. The static synchronous condenser is essentially developed based on power electronic equipment and does not have rotating elements, so the evaluation method based on inertia constant is not applicable. The second is a frequency response analysis method, which uses the frequency response characteristics of system disturbance to evaluate the inertia support capability. There are inertia evaluation indicators from different perspectives such as time domain, frequency domain and energy domain. However, this method is relatively complex to calculate, and does not consider the distribution characteristics of system frequency and inertia caused by the access of a large number of power electronic equipment. SUMMARY

[0005] The purpose of the present application is to provide a static synchronous condenser inertia evaluation method and system, which can solve the problem that the traditional inertia evaluation model is only applicable to the mechanical moment of inertia of synchronous generators, improve the accuracy of the inertia evaluation model, and accurately depict the support capability of the static synchronous condenser to the system after system disturbance.

[0006] In order to achieve the above purpose, the solution of the present application is:

[0007] A static synchronous condenser inertia evaluation method, comprising,

[0008] Obtaining system frequency of static synchronous compensator , virtual synchronous phase , virtual inertia constant and virtual damping coefficient ;

[0009] Applying power disturbance , obtaining angular frequency variation ;

[0010] Calculating inertia evaluation index to quantitatively evaluate inertia support capability of static synchronous compensator;

[0011] According to evaluation result and inertia demand of static synchronous compensator, adjusting virtual inertia constant and virtual damping coefficient .

[0012] Wherein, applying power disturbance , obtaining angular frequency variation , including,

[0013] According to virtual synchronous phase and system frequency , obtaining virtual angular frequency,

[0014]

[0015] According to the following formula, angular frequency variation is calculated,

[0016]

[0017] Wherein, respectively are system frequency before and after disturbance, respectively are measured phase before and after disturbance.

[0018] Wherein, inertia evaluation index is calculated, including,

[0019] According to one of the following two formulas, inertia evaluation index is calculated,

[0020]

[0021]

[0022] Wherein, s is slip rate.

[0023] Wherein, inertia support capability of static synchronous compensator is quantitatively evaluated, including,

[0024] When inertia evaluation index is greater, power disturbance Frequency change caused The smaller the virtual inertia constant and the virtual damping coefficient , the greater the inertia evaluation index , the stronger the anti-disturbance ability of the static synchronous compensator.

[0025] According to the evaluation result and the inertia demand of the static synchronous compensator, the virtual inertia constant and the virtual damping coefficient are adjusted, including,

[0026] The virtual inertia constant and the virtual damping coefficient are adjusted according to the following formula,

[0027] .

[0028] A static synchronous compensator inertia evaluation system, comprising,

[0029] A data acquisition module configured to obtain the system frequency , the virtual synchronous phase , the virtual inertia constant and the virtual damping coefficient of the static synchronous compensator;

[0030] A frequency response analysis module configured to apply a power disturbance to obtain an angular frequency change ;

[0031] An inertia evaluation module configured to calculate an inertia evaluation index to quantitatively evaluate the inertia support ability of the static synchronous compensator; and,

[0032] A parameter adjustment module configured to adjust the virtual inertia constant and the virtual damping coefficient according to the evaluation result and the inertia demand of the static synchronous compensator.

[0033] The frequency response analysis module applies a power disturbance to obtain an angular frequency change , including,

[0034] According to the virtual synchronous phase and the system frequency , a virtual angular frequency is obtained,

[0035]

[0036] The angular frequency change is calculated according to the following formula,

[0037]

[0038] wherein, are the system frequency before and after the disturbance respectively, are the measured phase before and after the disturbance respectively.

[0039] wherein, the inertia evaluation module calculates inertia evaluation indexes, including,

[0040] The inertia evaluation indexes are calculated according to one of the following two formulas ,

[0041]

[0042] .

[0043] wherein, the inertia evaluation module quantitatively evaluates the inertia support capability of the static synchronous compensator, including,

[0044] The larger the inertia evaluation index is, the smaller the frequency change caused by the power disturbance is, which is related to the virtual inertia constant and the virtual damping coefficient , the larger the values of the two parameters are, the larger the inertia evaluation index is, and the stronger the anti-disturbance capability of the static synchronous compensator is.

[0045] wherein, the parameter adjustment module adjusts the virtual inertia constant and the virtual damping coefficient according to the evaluation result and the inertia demand of the static synchronous compensator, including,

[0046] The virtual inertia constant and the virtual damping coefficient are adjusted according to the following formula,

[0047] .

[0048] ​After adopting the above scheme, this invention constructs a static synchronous condenser structure based on grid construction technology, which can provide active support for the new energy power system. Furthermore, it employs virtual synchronization control technology to enable the static synchronous condenser to possess inertial response capability. To evaluate the inertial response performance of the static synchronous condenser, an equivalent inertial index characterizing its inertial support capability is extracted based on the virtual synchronization control model. The larger the equivalent inertial index, the stronger the static synchronous condenser's anti-disturbance capability. Based on this, a static synchronous condenser inertial evaluation method is proposed: Step 1 is data acquisition, used to collect the static synchronous condenser's output power, system frequency, virtual synchronization phase, and control parameters in real time; Step 2 is frequency response analysis, applying power disturbances to the system and calculating frequency deviation, frequency change rate, and inertial response power based on the collected data; Step 3 is inertial evaluation, calculating inertial evaluation indices based on dynamic response data to quantitatively evaluate the static synchronous condenser's inertial support capability.

[0049] On the one hand, this invention extracts evaluation indicators based on the virtual inertia control model of power electronic equipment, which solves the drawback that the traditional inertia evaluation model is only applicable to the mechanical rotational inertia of synchronous generators; on the other hand, it takes into account the distribution characteristics of system frequency and inertia caused by the connection of a large number of power electronic devices, making the inertia evaluation model more accurate and able to accurately characterize the support capability of the stationary synchronous condenser for the system after system disturbance. Attached Figure Description

[0050] Figure 1 This is a flowchart of the inertia evaluation method of the present invention;

[0051] Figure 2 This is a schematic diagram of the topology of a stationary synchronous condenser;

[0052] Figure 3 It is a virtual control block diagram;

[0053] Figure 4 This is a block diagram of the inertia assessment system of the present invention;

[0054] Figure 5 This is the frequency response characteristic of the simulation case of this invention. Detailed Implementation

[0055] The technical solution and beneficial effects of the present invention will be described in detail below with reference to the accompanying drawings.

[0056] This invention provides a method and system for evaluating the inertia of a static synchronous condenser. The static synchronous condenser studied adopts a high-voltage cascaded full-bridge topology and a dynamic reactive power compensation device implemented using supercapacitor short-time energy storage technology. (In conjunction with...) Figure 2As shown, the power module unit is the core component of the stationary synchronous condenser. Its components include an AC / DC power converter (i.e., H-bridge circuit, PCS), interface circuit, supercapacitor, bypass switch, etc. The interface unit mainly realizes the monitoring, management, and protection functions of the supercapacitor. The supercapacitor mainly realizes energy storage and provides short-term active power output.

[0057] Among them, the DC side of the AC / DC converter is connected to conventional thin-film capacitors, supercapacitors or energy storage batteries and other voltage source devices, which can invert and output AC sinusoidal voltage with adjustable amplitude and phase on the AC side; by adjusting the amplitude and phase angle of the AC voltage output by the static synchronous condenser, reactive and active power exchange between the static condenser and the power system can be realized, achieving four-quadrant operation and following the most basic AC power flow formula.

[0058] A virtual inertia response model (hereinafter referred to as the virtual inertia response model) is constructed based on virtual synchronous control technology. This model enables the static synchronous condenser to possess not only reactive power and voltage support capabilities but also inertia support capabilities, thus suppressing excessively rapid changes in system frequency after system disturbances. Simultaneously, an equivalent inertia index characterizing the inertia support capability is extracted based on this virtual inertia response model. This characterizes the inertia support capability of the system after the static synchronous condenser is connected to the node.

[0059] Specifically, the rotor motion equation of the virtual synchronous machine is:

[0060] (1)

[0061] In the formula, These are the virtual phase, virtual angular velocity, virtual inertia, and virtual damping coefficient of the stationary synchronous conversion camera, respectively. These are the set power and output electromagnetic power of the virtual synchronous condenser, respectively; The standard angular velocity has a value of ; These are the system frequency and the standard frequency, respectively; s is the slip.

[0062] Cooperate Figure 3 As shown, a power disturbance is applied to the virtual synchronization control model shown in equation (1). The corresponding frequency change is ,but:

[0063] (2)

[0064] Simplifying equation (2), we get:

[0065] (3)

[0066] From equation (3), it can be seen that when The larger the power disturbance Caused frequency changes A smaller value can be used as an evaluation indicator of the inertia support capability of a stationary synchronous condenser. It is mainly related to two parameters: the virtual inertia constant of the stationary synchronous condenser. and virtual damping coefficient The larger the values ​​of the two parameters, the higher the equivalent inertia index. The larger the value, the stronger the anti-disturbance capability of the static synchronous condenser.

[0067] Based on the above analysis, this invention provides a method for evaluating the inertia of a static synchronous condenser, comprising three steps: data acquisition, frequency response analysis, and inertia evaluation, in conjunction with... Figure 1 As shown, the specific steps are as follows:

[0068] Step 1: Data Acquisition: Used to acquire the output power of the stationary synchronous condenser in real time. System frequency Virtual synchronization phase and control parameters (including virtual inertia constant) and virtual damping coefficient );

[0069] Step 2: Frequency Response Analysis: Applying a power disturbance to the system Based on the collected data, the virtual angular velocity is calculated by back-calculating the system frequency using the following formula:

[0070] (4)

[0071] Then calculate the change in angular frequency, using the following formula:

[0072] (5)

[0073] In the formula, These are the system frequencies before and after the disturbance, respectively; These are the measured phases before and after the disturbance, respectively.

[0074] Step 3: Inertia Assessment: Calculate the inertia assessment index to quantitatively evaluate the inertia support capacity of the static synchronous condenser. The inertia assessment index can be calculated using two methods: one is using measured data, with the following formula:

[0075] (6)

[0076] Secondly, the calculation is based on fixed parameters, as shown in the following formula:

[0077] (7)

[0078] The evaluation indexes calculated by the two methods are similar in magnitude. The former relies on applying disturbances to the power grid and is suitable for evaluating the inertia of stationary synchronous condensers that have already been connected to the grid, while the latter can be evaluated without applying disturbances to the power grid and is more suitable for adjusting the parameters of stationary synchronous condensers.

[0079] Cooperate Figure 4 As shown, the present invention also provides a static synchronous condenser inertia evaluation system, comprising the following modules:

[0080] Data acquisition module: Employs measurement technologies such as PMU to measure the output power of the stationary synchronous condenser in real time. System frequency Virtual synchronization phase and control parameters, etc.;

[0081] Frequency response analysis module: Apply a disturbance to the system and calculate the change in angular frequency according to equation (5), which is used to calculate the inertia evaluation coefficient;

[0082] Inertia assessment module: Calculate the inertia assessment coefficient according to formula (6) or formula (7) to quantitatively assess the inertia support capability of the stationary synchronous condenser under the current state;

[0083] Parameter tuning module: Based on the evaluation results and the system's inertia requirements for the stationary synchronous condenser, adjust the virtual inertia constant according to equation (7). and virtual damping coefficient The inertia of the stationary synchronous camera is customized.

[0084] This invention uses the IEEE 39-bus system as an example for simulation analysis. All high-voltage substations are equipped with PMUs, which can collect grid operating parameters, including phase parameters, in real time. Assuming that nodes 2 and 27 are connected to static synchronous condensers, named nodes A and B, the inertia characteristics of the two condensers are evaluated. At t=0, a power disturbance is applied at node 15, increasing the power by 10MW. The corresponding frequency response curves of nodes 2 and 27 are shown below. Figure 5 As shown.

[0085] The inertia indices calculated according to equations (6) and (7) are the measured indices and the fixed parameter indices, respectively, and the results are shown in Table 1.

[0086] Table 1 Inertia Index

[0087] Unit No. Actual Index Fixed Parameter Index Error Unit A 12.57 12.23 -2.7% Unit B 10.98 11.14 1.6%

[0088] As can be seen from the table, the measured index calculated according to formula (6) and the fixed parameter index calculated based on formula (7) are not much different, which shows the accuracy of the inertia evaluation index proposed in this invention.

[0089] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0090] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0091] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0092] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0093] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0094] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for evaluating the inertia of a stationary synchronous condenser, characterized in that: include, Obtain the system frequency of the stationary synchronous condenser Virtual synchronization phase Virtual inertia constant and virtual damping coefficient ; Apply power disturbance The change in angular frequency is obtained. ; The inertia evaluation index is calculated to quantitatively evaluate the inertia support capability of the static synchronous condenser. Based on the evaluation results and the inertia requirements for the stationary synchronous condenser, the virtual inertia constant is adjusted. and virtual damping coefficient .

2. The method as described in claim 1, characterized in that: Apply power disturbance The change in angular frequency is obtained. , include, According to the virtual synchronization phase and system frequency The virtual angular frequency is obtained. ， The change in angular frequency can be calculated using the following formula. , ， in, These are the system frequencies before and after the disturbance, respectively. These are the measured phases before and after the disturbance, respectively.

3. The method as described in claim 1, characterized in that: The calculated inertia evaluation indicators include, The inertia evaluation index is calculated using one of the following two formulas. , ， ， Where s is the slip ratio.

4. The method as described in claim 1, characterized in that: Quantitatively evaluate the inertia support capability of a stationary synchronous modulator, including: When inertia evaluation index The larger the power disturbance Caused frequency changes The smaller it is, the closer it is to the virtual inertia constant. and virtual damping coefficient The larger the values ​​of the two parameters, the higher the inertia assessment index. The larger the value, the stronger the anti-disturbance capability of the static synchronous condenser.

5. The method as described in claim 1, characterized in that: Based on the evaluation results and the inertia requirements for the stationary synchronous condenser, the virtual inertia constant is adjusted. and virtual damping coefficient ,include, Adjust the virtual inertia constant according to the following formula. and virtual damping coefficient , 。 6. A system for evaluating the inertia of a stationary synchronous condenser, characterized in that: include, The data acquisition module is configured to acquire the system frequency of the stationary synchronous condenser. Virtual synchronization phase Virtual inertia constant and virtual damping coefficient ; The frequency response analysis module is configured to apply a power perturbation. The change in angular frequency is obtained. ; The inertia assessment module is configured to calculate inertia assessment indices to quantitatively evaluate the inertia support capability of the static synchronous condenser; and, The parameter tuning module is configured to adjust the virtual inertia constant based on the evaluation results and the inertia requirements for the stationary synchronous condenser. and virtual damping coefficient .

7. The system as described in claim 6, characterized in that: Frequency response analysis module applies power perturbation The change in angular frequency is obtained. , include, According to the virtual synchronization phase and system frequency The virtual angular frequency is obtained. ， The change in angular frequency can be calculated using the following formula. , ， in, These are the system frequencies before and after the disturbance, respectively. These are the measured phases before and after the disturbance, respectively.

8. The system as described in claim 6, characterized in that: The inertia assessment module calculates inertia assessment metrics, including: The inertia evaluation index is calculated using one of the following two formulas. , ， 。 9. The system as described in claim 6, characterized in that: The inertia assessment module quantitatively evaluates the inertia support capability of a stationary synchronous condenser, including: When inertia evaluation index The larger the power disturbance Caused frequency changes The smaller it is, the closer it is to the virtual inertia constant. and virtual damping coefficient The larger the values ​​of the two parameters, the higher the inertia assessment index. The larger the value, the stronger the anti-disturbance capability of the static synchronous condenser.

10. The system as described in claim 6, characterized in that: The parameter tuning module adjusts the virtual inertia constant based on the evaluation results and the inertia requirements for the stationary synchronous condenser. and virtual damping coefficient ,include, Adjust the virtual inertia constant according to the following formula. and virtual damping coefficient , 。

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