A real-time simulation test method for suppressing low-frequency oscillation and ultra-low-frequency oscillation of power grid

Abstract

The application discloses a kind of real-time simulation test methods for inhibiting power grid low-frequency oscillation and ultra-low frequency oscillation, belong to power grid technical field, this method includes the following steps: build real-time simulation test platform based on real-time simulator and generator exciter;Establish power grid model and run in real-time simulator;Real-time simulator exports the electrical quantity and switch quantity of the kth unit in power grid model to generator exciter;The PSS controller constant value parameter of the kth unit is set in generator exciter, and then the excitation voltage is output to real-time simulator;The excitation voltage received by real-time simulator is added to the kth unit, the controller of the application is used Field engineering actual commissioning controls power grid digital model, carries out the research of inhibiting power grid low-frequency oscillation and ultra-low frequency oscillation;Simultaneously, the inhibitory effect of PSS controller installation site on power grid low-frequency oscillation and ultra-low frequency oscillation is tested quickly.

Description

Technical Field

[0001] This invention relates to the technical field of power grid technology, and in particular to a real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids. Background Technology

[0002] Low-frequency oscillations in power grids refer to oscillations in the rotor angle, speed, and related electrical quantities of generators, such as line power and bus voltage, with an approximately constant or increasing amplitude. The oscillation frequency is generally between 0.1Hz and 2.5Hz, as described in DL / T 961-2020 "Terminology for Power Grid Dispatch Standards". Ultra-low frequency oscillations are generally below 0.1Hz.

[0003] Causes of low-frequency and ultra-low-frequency oscillations: When generators are running in parallel in a power system, relative swaying between generator rotors occurs under disturbances, and oscillations continue when there is a lack of damping. Low-frequency oscillations are generated with the interconnection of power grids. In the early stages of grid interconnection, the connection between synchronous generators is close, and the damping windings can generate sufficient damping, so low-frequency oscillations rarely occur. With the expansion of the scale of power grid interconnection, the widespread adoption of high-amplification fast excitation technology, and the fact that the operation of the power grid is closer to the stability limit under the influence of economic and environmental factors, low-frequency oscillations have been observed in many power grids around the world. They can be roughly divided into local mode oscillations and inter-regional mode oscillations. Generally speaking, the more units involved and the wider the area, the lower the oscillation frequency. It is generally believed that low-frequency oscillations are the power swaying on the tie line after the power system is disturbed. The dynamic instability of the system is caused by divergent oscillations due to insufficient damping or even negative damping after the disturbance. The main factors of instability are insufficient electrical damping of the system or lack of appropriate active power coordination, which are usually caused by the following types of disturbances:

[0004] (1) Disconnection; (2) Transmission line fault or protection malfunction; (3) Circuit breaker equipment accident; (4) Loss of load. Disturbance phenomena generally go through the process of generation, propagation and dissipation. During the propagation process, new disturbances may be caused. At the same time, the operation against the disturbance itself is also a disturbance. Therefore, these situations are often not isolated, but interconnected, presenting multiple phenomena in time and space. This is the actual physical background of the existence of multiple disturbances. The continuous deterioration of the interaction will eventually lead to system instability and disconnection, forming a large-scale power outage accident.

[0005] In summary, existing methods for suppressing low-frequency grid oscillations involve establishing a grid model in a simulation software environment, including generator models, governor models, exciter models, and PSS models. These digital models exhibit modeling discrepancies with the controllers actually deployed in field projects, making it impossible to test the effectiveness of the actual controllers in suppressing low-frequency grid oscillations. Furthermore, the controller parameters are difficult to fully tune through theoretical calculations. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problem that existing real-time simulation test methods for suppressing low-frequency and ultra-low-frequency oscillations in power grids have modeling discrepancies between the digital model and the actual controllers in field engineering, this invention is proposed.

[0008] Therefore, the purpose of this invention is to provide a real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids, comprising,

[0010] A real-time simulation test platform based on a real-time simulator and a generator exciter was built, and a power grid model was established and run in the real-time simulator.

[0011] The real-time simulator outputs the electrical and switching quantities of the k-th unit in the power grid model to the generator exciter.

[0012] The setpoint parameters of the PSS controller of the kth unit are set in the generator exciter, and then the excitation voltage is output to the real-time simulator.

[0013] The excitation voltage received by the real-time simulator is applied to the k-th unit;

[0014] The experiment was conducted to trigger low-frequency and ultra-low-frequency oscillations in the power grid, and the power grid waveform data after the k-th unit was added to the PSS controller was recorded.

[0015] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid as described in this invention, the real-time simulator establishes a power grid model based on power grid mode data.

[0016] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in the power grid as described in this invention, the power grid model includes models of all generators, substations, converter stations, loads, overhead lines, cables, HVDC, and high-voltage direct current transmission.

[0017] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in the power grid according to the present invention, the power grid model is as follows:

[0018]

[0019]

[0020] P m P is the mechanical torque; e δ is the electromagnetic torque; δ is the angular displacement of the rotor about the synchronously rotating reference axis; T j P is the motor torque; ω0 is the synchronous speed; Δω is the difference between the rotor's electrical angular velocity and the angular velocity between the synchronous rotating coordinate axis, i.e., the relative angular velocity; D is the proportionality coefficient of all torques that are proportional to the change in speed; where P m P e ω0 is represented in per-unit values.

[0021] in:

[0022]

[0023] E′ q Let be the q-axis transient potential, where:

[0024] E′ q =U t +jx′ d i (2);

[0025] U t x′ is the terminal voltage; d denoted as d-axis transient reactance; i is the excitation current; j is a constant.

[0026] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid as described in this invention, the real-time simulator sends the electrical and switching quantities of the k-th generator in the power grid model to the GTAO and GTDO boards, and the generator exciter receives the analog and digital signals from the GTAO and GTDO boards.

[0027] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid as described in this invention, the exciter outputs an excitation voltage signal to the GTAI board after PSS control function calculation. The real-time simulator collects the analog signal from the GTAI board and applies the analog excitation voltage signal to the excitation voltage of the k-th generator.

[0028] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid as described in this invention, the method involves triggering disturbances such as three-phase short-circuit grounding faults, line tripping, DC single-pole blocking, and DC double-pole blocking on the near-zone busbar of the power station, thereby triggering low-frequency and ultra-low-frequency oscillations of the power grid.

[0029] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid as described in this invention, the PSS controller is selected as a PSS4B controller.

[0030] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in the power grid as described in this invention, the two-stage lead-lag elements of the upper and lower channels of the PSS4B controller are set with the same parameter, namely T. L3 =T L9 T L4 =T L10 T L5 =T L11 T L6 =T L12 and order

[0031]

[0032] The low-frequency branch consists of a differential filter, a phase compensation, and a gain circuit. The center frequency of the differential filter is FL, and the coefficient R is generally taken as 1.2. Thus, the PSS4B parameters are converted into the differential filter parameters FL(I,H), the phase compensation parameters TL(I,H)3, TL(I,H)4, TL(I,H)5, TL(I,H)6, and the gain circuit parameter KL(I,H) for each branch.

[0033] As a preferred embodiment of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid as described in this invention, the PSS controller is selected as a PSS4B controller.

[0034] The beneficial effects of this invention are:

[0035] 1. This invention does not require PSS modeling. It uses the actual hardware controller in the field to connect to the power grid simulation model to conduct experiments on the suppression effect of PSS on low-frequency oscillation and ultra-low-frequency oscillation. It does not require PSS modeling, thus ensuring the most accurate control effect of PSS controller on the power grid.

[0036] 2. The real-time simulation test platform in this invention is simple to construct:

[0037] a. No need to repeatedly build experimental platforms;

[0038] b. Only one generator exciter is needed to test the suppression effect of PSS device on low-frequency and ultra-low-frequency oscillations of the power grid on each generator in the entire network. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0040] Figure 1 This is a functional block diagram of the real-time simulation test platform for the real-time simulation test method of suppressing low-frequency and ultra-low-frequency oscillations in the power grid according to the present invention.

[0041] Figure 2 This is a schematic diagram illustrating the oscillation suppression effect of the first generator equipped with a PSS controller in Example 2 of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in the power grid according to the present invention.

[0042] Figure 3 This is a schematic diagram illustrating the oscillation suppression effect of the second generator equipped with a PSS controller in Example 3 of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in the power grid according to the present invention.

[0043] Figure 4 This is a schematic diagram of the PSS4B low-frequency branch structure in the center frequency form of Example 4 of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid according to the present invention.

[0044] Figure 5 This is a schematic diagram of the PSS4B mathematical model in Example 4 of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in the power grid according to the present invention.

[0045] Figure 6 This is a schematic diagram of the low- and mid-frequency and high-frequency input signal preprocessing branches of PSS4B in Example 4 of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid according to the present invention.

[0046] Figure 7 The Bode plots of the input signal preprocessing branches of PSS4B and PSS2B in the low-mid frequency band and high-frequency band of the real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of the power grid described in Example 4 of the present invention are shown. Detailed Implementation

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0049] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0050] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0051] Example 1

[0052] Reference Figure 1 This invention discloses a real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids, comprising the following steps:

[0053] First, a real-time simulation test platform based on a real-time simulator and a generator exciter is built:

[0054] The real-time simulator establishes a power grid model based on power grid mode data. The power grid model includes models of all generators, substations, converter stations, loads, overhead lines, cables, HVDC, and high-voltage direct current transmission. The power grid model is run in real time by the real-time simulator. The terminal voltage, terminal current, synchronization voltage, and excitation current of any generator in the power grid model are output to the generator exciter through the RTDS dedicated communication board GTAO. The terminal circuit breaker position signal of any generator in the power grid model is output to the generator exciter through the RTDS dedicated communication board GTDO. Preferably, the real-time simulator is an RTDS simulator.

[0055] The generator exciter receives the terminal voltage, terminal current, synchronization voltage, excitation current, and terminal circuit breaker position signal output by the real-time simulator, and outputs the excitation voltage of a certain unit to the real-time simulator through the RTDS dedicated communication board GTAI. Preferably, the generator exciter adopts NARI Electric Control NES6100.

[0056] Then, a power grid model is built and run in a real-time simulator:

[0057] Wherein: the power grid model is:

[0058]

[0059]

[0060] P m P is the mechanical torque; e δ is the electromagnetic torque; δ is the angular displacement of the rotor about the synchronously rotating reference axis; T j P is the motor torque; ω0 is the synchronous speed; Δω is the difference between the rotor's electrical angular velocity and the angular velocity between the synchronous rotating coordinate axis, i.e., the relative angular velocity; D is the proportionality coefficient of all torques that are proportional to the change in speed; where P m P e ω0 is represented in per-unit values.

[0061] in:

[0062]

[0063] E′ q Let be the q-axis transient potential, where:

[0064] E′ q =U t +jx′ d i (2);

[0065] U t x′ is the terminal voltage; d denoted as d-axis transient reactance; i is the excitation current; j is a constant.

[0066] The real-time simulator outputs the electrical and switching quantities of the k-th unit in the power grid model to the generator exciter. This step only requires switching the output of the electrical and switching quantities of the corresponding unit in the real-time simulator model to switch to the test of the next unit.

[0067] In the generator exciter, set the PSS controller settings for the k-th unit, and then output the excitation voltage to the real-time simulator. This step only requires setting the corresponding PSS parameters for the generator exciter; no changes to hardware configuration or wiring are needed. Then, you can switch to testing the next unit. Specifically:

[0068] The setpoint parameters for the PSS controller of the k-th unit are selected from the differential filter parameters, acceleration power, and system frequency.

[0069] The excitation voltage received by the real-time simulator is applied to the k-th unit. After the real-time simulator samples the excitation voltage of the exciter, it switches to the model of the corresponding unit, and then it can switch to the test of the next unit.

[0070] The experiment was conducted to trigger low-frequency and ultra-low-frequency oscillations in the power grid. The methods for triggering low-frequency and ultra-low-frequency oscillations in the power grid can include disconnecting one unit in the power grid model, increasing the transmission power of the HVDC model, and disconnecting loads in the power grid model. Specifically, it triggers low-frequency and ultra-low-frequency oscillations in the power grid by triggering fault disturbances such as three-phase short-circuit grounding faults on the near-zone bus of the power plant, line tripping, DC single-pole blocking, and DC double-pole blocking.

[0071] Record the grid waveform data after the k-th unit is connected to the PSS controller, and then conduct the test on the next unit.

[0072] This invention eliminates the need for PSS modeling. It uses an actual field hardware controller connected to the power grid simulation model to conduct experiments on the suppression effect of PSS on low-frequency and ultra-low-frequency oscillations. The absence of PSS modeling ensures the most accurate control effect of the PSS controller on the power grid.

[0073] The real-time simulation test platform in this invention is simple to construct: a. It does not require repeated construction of test platforms; b. Only one generator exciter is needed to test the suppression effect of PSS device on low-frequency and ultra-low-frequency oscillations of the power grid on each generator in the entire network.

[0074] Example 2

[0075] like Figure 2 This embodiment specifically describes the implementation of a real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids using a first generator:

[0076] A real-time simulation test platform including a real-time simulator and a generator exciter was built.

[0077] Build a power grid model and run it in a real-time simulator.

[0078] Start the generator exciter and set the PSS controller parameters for the first generator in the generator exciter.

[0079] The real-time simulator sends the electrical and switching quantities of the first generator in the power grid model to the GTAO and GTDO boards, and the generator exciter receives the analog and digital signals from the GTAO and GTDO boards.

[0080] The exciter, after processing by the PSS control function, outputs an excitation voltage signal to the GTAI board. The real-time simulator acquires the analog signal from the GTAI board and applies this analog excitation voltage signal to the excitation voltage of the first generator.

[0081] Triggering power grid faults, including but not limited to three-phase short-circuit ground faults, line tripping faults, and DC blocking faults.

[0082] The active power and rotor frequency of the first generator were observed and the data were recorded to a hard disk.

[0083] like Figure 2 As shown, after the PSS function was installed on the first generator in Unit 1, a DC single-pole blocking fault was triggered in the power grid. The order from top to bottom is: DC power, power of the first generator, and rotor frequency of the first generator. At the 6th second, the DC single-pole blocking occurred, and the power dropped from 5000MW to 3000MW. The power and frequency of the first generator exhibited an ultra-low frequency oscillation of 0.05Hz. This proves that installing PSS on the first generator was ineffective.

[0084] Example 3

[0085] like Figure 3 This embodiment specifically relates to the implementation of a real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids on a second generator:

[0086] Build a real-time simulation test platform that includes a real-time simulator and a generator exciter;

[0087] Build a power grid model and run it in a real-time simulator;

[0088] Start the generator exciter and set the PSS controller parameters for the second generator in the generator exciter.

[0089] The real-time simulator sends the electrical and switching quantities of the second generator in the power grid model to the GTAO and GTDO boards, and the generator exciter receives the analog and digital signals from the GTAO and GTDO boards.

[0090] The exciter, after processing by the PSS control function, outputs an excitation voltage signal to the GTAI board. The real-time simulator collects the analog signal from the GTAI board and applies the analog excitation voltage signal to the excitation voltage of the second generator.

[0091] Triggering power grid faults, including but not limited to three-phase short-circuit ground faults, line tripping faults, DC blocking faults, etc.

[0092] The active power and rotor frequency of the second generator were observed and the data were recorded to a hard disk.

[0093] For example, after installing the PSS function on the second generator, a DC unipolar blocking fault was triggered in the power grid. The data of the second generator, from top to bottom, were: DC power, generator power, and rotor frequency. At the 6th second, the DC unipolar blocking occurred, and the power dropped from 5000MW to 3000MW. The power and frequency of the second generator essentially stopped oscillating at the 80th second. This demonstrates that installing PSS on the second generator has a significant effect on suppressing ultra-low frequency oscillations.

[0094] The comparison of the overfrequency oscillation suppression effects of the first and second generators after installing the PSS function clearly shows that different generators have different suppression effects on ultra-low frequency oscillations. However, without using PSS modeling, the most accurate control data of the PSS controller on the power grid can still be measured. That is, a simple test method can be used to perform simple and effective suppression data measurement on multiple different generators.

[0095] Example 4

[0096] like Figure 4-7 In this embodiment, the PSS controller setpoint parameters are selected from the differential filter stage parameters, acceleration power, and system frequency, and the PSS controller is selected as the PSS4B controller.

[0097] The PSS4B is essentially composed of three differential filters, each implementing bandpass filtering at its corresponding center frequency. Taking the low-frequency branch as an example, the two-stage lead-lag stages of both the upper and lower channels are set with the same parameter, namely T. L3 =T L9 T L4 =T L10 T L5 =T L11 T L6 =T L12 And order:

[0098]

[0099] The low-frequency branch consists of a differential filter, a phase compensation, and a gain circuit. The center frequency of the differential filter is FL, and the coefficient R is generally taken as 1.2. Thus, the PSS4B parameters are converted into the differential filter parameters FL(I,H), the phase compensation parameters TL(I,H)3, TL(I,H)4, TL(I,H)5, TL(I,H)6, and the gain circuit parameter KL(I,H) for each branch.

[0100] Similar to the PSS2B, the PSS4B employs a dual-channel input signal. Both frequency and electromagnetic power signals have their advantages and disadvantages as input signals for the PSS: frequency signals are the most intuitive, but they have significant high-frequency noise; electromagnetic power signals do not have high-frequency noise issues, but based on the assumption that ΔPm≈0 holds true, this assumption does not hold true when the generator's load normally increases or decreases, leading to a "reactive power reversal" problem when using electromagnetic power as the input signal. Therefore, the PSS4B utilizes filters, using frequency signals for the low and mid-frequency bands and electromagnetic power signals for the high-frequency band. Both frequency and power signals must be pre-processed before being input into the PSS4B.

[0101] Then, the preprocessing branches of the low-mid frequency and high-frequency input signals are analyzed, and Bode plots are established, such as... Figure 7 As shown, the left side represents the amplitude of PSS4B under low-mid-frequency and high-frequency input signals, while the right side represents the amplitude of PSS2B under low-mid-frequency and high-frequency input signals. By analyzing the Bode plot, it can be seen that, compared to PSS2B, PSS4B exhibits a smaller amplitude decrease as the frequency gradually increases in the low-mid-frequency range, thus maintaining a more stable overall amplitude. Furthermore, when dealing with high-frequency input signals, PSS4B shows an increase in amplitude, whereas PSS2B only gradually decreases with increasing frequency. Therefore, PSS4B has an advantage in terms of controllability.

[0102] The PSS4B has three branches: low, medium, and high, offering more parameters and more flexible frequency characteristics, providing greater freedom compared to the traditional PSS.

[0103] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0104] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0105] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids, characterized in that: include, A real-time simulation test platform based on a real-time simulator and a generator exciter was built, and a power grid model was established and run in the real-time simulator. The real-time simulator outputs the electrical and switching quantities of the k-th unit in the power grid model to the generator exciter. The setpoint parameters of the PSS controller of the kth unit are set in the generator exciter, and then the excitation voltage is output to the real-time simulator. The excitation voltage received by the real-time simulator is applied to the k-th unit; The experiment was conducted to trigger low-frequency and ultra-low-frequency oscillations in the power grid, and the power grid waveform data after the k-th unit was connected to the PSS controller was recorded. The power grid model is as follows: For mechanical torque; Electromagnetic torque; This represents the angular displacement of the rotor relative to a synchronously rotating reference axis; It is the torque of the motor; Synchronous speed; ω is the difference between the rotor's electrical angular velocity and the angular velocity of the synchronous rotating coordinate axis, i.e., the relative angular velocity; D is the proportionality coefficient for all torques that are proportional to the change in rotational speed; where , , Represented by per-unit value, in: （1） Let be the q-axis transient potential, where: （2）； This refers to the terminal voltage. d is the d-axis transient reactance; i is the excitation current; j is a constant. The PSS controller is selected as the PSS4B controller. Set the two-stage lead-lag circuits of the upper and lower channels of the PSS4B controller to the same parameter, namely T. L3 = T L9 T L4 =T L10 T L5 = T L11 T L6 = T L12 and order The low-frequency branch consists of a differential filter, a phase compensation, and a gain circuit. The center frequency of the differential filter is FL, and the coefficient R is 1.

2. Thus, the PSS4B parameters are converted into the differential filter parameters FL(I, H), the phase compensation parameters TL(I, H)3, TL(I, H)4, TL(I, H)5, TL(I, H)6, and the gain circuit parameter KL(I, H) for each branch.

2. The real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids as described in claim 1, characterized in that: The real-time simulator builds a power grid model based on power grid mode data.

3. The real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids as described in claim 2, characterized in that: The power grid model includes all generator models, substation models, converter station models, load models, overhead line models, cable models, HVDC models, and high-voltage direct current transmission models.

4. The real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations of power grids as described in claim 1, characterized in that: The real-time simulator sends the electrical and switching quantities of the k-th generator in the power grid model to the GTAO and GTDO boards, and the generator exciter receives the analog and digital signals from the GTAO and GTDO boards.

5. The real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids as described in claim 4, characterized in that: The exciter, after processing by the PSS control function, outputs an excitation voltage signal to the GTAI board. The real-time simulator acquires the analog signal from the GTAI board and applies this analog excitation voltage signal to the excitation voltage of the k-th generator.

6. The real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids as described in claim 1, characterized in that: By triggering disturbances such as three-phase short-circuit grounding faults, line tripping, DC single-pole blocking, and DC double-pole blocking on the near-zone busbar of the power plant, low-frequency oscillations and ultra-low-frequency oscillations of the power grid are subsequently triggered.

7. The real-time simulation test method for suppressing low-frequency and ultra-low-frequency oscillations in power grids as described in claim 1, characterized in that: The PSS controller setpoint parameters are selected from the differential filter stage parameters, acceleration power, and system frequency.

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