Method and device for testing voltage amplitude and phase jump of network-forming unit

Abstract

The invention belongs to the technical field of network construction type unit testing, and provides a network construction type unit voltage amplitude and phase jump testing method and device. The method comprises the following steps: determining a voltage amplitude, a first voltage amplitude before phase jump and a first voltage phase according to an internal potential of a network-forming unit, an equivalent potential connected to a power grid, internal impedance and system impedance; according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance, determining a voltage amplitude, a second voltage amplitude after the phase jumps and a second voltage phase; wherein the grounding impedance is used for enabling the voltage amplitude and the voltage phase of the terminal voltage of the converter of the grid-forming unit to jump; and according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase, determining the short-circuit impedance required by the network-forming unit in the voltage amplitude and phase jump test scene. The invention provides a testing method suitable for the working condition of voltage phase and amplitude jump of a grid-forming type unit.

Description

Technical Field

[0001] The present application belongs to the field of power grid control technology, and more particularly to the field of grid-forming unit testing technology, and more particularly to a method and device for testing voltage amplitude and phase jump of a grid-forming unit. Background Art

[0002] At present, with the gradual promotion and application of grid-connected new energy units and energy storage, there are more and more devices that can perform active support in the station. Each device has different principles, large differences in transient response characteristics, and large differences in adjustment capabilities. Because the technology is still in the development stage, the test standards for its transient response characteristics are still imperfect. Since 2020, technical personnel in the industry have successively proposed guiding procedures for the testing of grid-connected units, all of which require grid-connected units to have the ability to operate stably when voltage phase and amplitude jumps occur in the power system.

[0003] The current standards for the response characteristics of new energy equipment, such as GB_T19963.1-2021 "Technical Regulations for Wind Farm Access to Power System" and GB / T19964-2024 "Technical Regulations for Photovoltaic Power Station Access to Power System", mainly restrict grid-type converters, so there are only requirements for responding to voltage jumps (increases or drops), that is, high and low voltage ride-through. Therefore, there is currently a lack of test methods for simultaneously examining the response characteristics of grid-type units under voltage phase and amplitude jump disturbances. Summary of the invention

[0004] The present invention provides a method and device for testing the voltage amplitude and phase jump of a grid-type unit, aiming to solve the technical problem that there is a lack of a voltage and phase angle jump detection method suitable for a grid-type unit in the prior art.

[0005] In order to solve the technical problems in the background technology of this application, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a method for testing voltage amplitude and phase jump of a grid-type unit, the method comprising:

[0007] Determine the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-forming unit, the equivalent potential of the grid, the internal impedance and the system impedance;

[0008] Determine the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump;

[0009] The short-circuit impedance required for the grid-type unit in a voltage amplitude and phase jump test scenario is determined according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase.

[0010] In some embodiments of the present application, the equivalent potential is the potential of the three-phase ideal voltage source connected to the power grid;

[0011] The internal impedance is the equivalent impedance from the position corresponding to the internal potential to the machine end;

[0012] The system impedance is the equivalent impedance from the machine end to the access power grid.

[0013] In some embodiments of the present application, a method for testing voltage amplitude and phase jump of a grid-type unit further includes:

[0014] When the grid-type unit does not have voltage and current inner loop control and has virtual impedance, the internal impedance is determined according to the box transformer impedance, filter impedance and the virtual impedance of the grid-type unit.

[0015] In some embodiments of the present application, a method for testing voltage amplitude and phase jump of a grid-type unit further includes:

[0016] When the grid-type unit does not have voltage and current inner loop control and virtual impedance, the internal impedance is determined according to the box transformer impedance and filter impedance of the grid-type unit.

[0017] In some embodiments of the present application, a method for testing voltage amplitude and phase jump of a grid-type unit further includes:

[0018] When the grid-type generator set has voltage and current inner loop control and virtual impedance, the internal impedance is determined according to the box transformer impedance and the virtual impedance of the grid-type generator set.

[0019] In some embodiments of the present application, a method for testing voltage amplitude and phase jump of a grid-type unit further includes:

[0020] When the grid-type generator set has voltage and current inner loop control and does not have virtual impedance, the internal impedance is determined according to the impedance of the box-type transformer of the grid-type generator set.

[0021] In some embodiments of the present application, a method for testing voltage amplitude and phase jump of a grid-type unit is provided, and the short-circuit impedance required by the grid-type unit in a voltage amplitude and phase jump test scenario is determined according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase, including:

[0022] Determine voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase;

[0023] Generating a cluster of curves of the voltage amplitude jump amount and the voltage phase jump amount as the ground impedance changes according to the voltage amplitude jump amounts and the voltage phase jump amounts corresponding to the multiple ground impedances;

[0024] The short-circuit impedance is determined based on the family of curves.

[0025] In a second aspect, the present invention provides a device for testing voltage amplitude and phase jump of a grid-type unit, the device comprising:

[0026] A pre-jump value determination module is used to determine the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-forming unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance;

[0027] A post-jump value determination module, used to determine the second voltage amplitude and second voltage phase after the voltage amplitude and phase jump according to the ground impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the ground impedance is used to cause the voltage amplitude and voltage phase of the converter terminal voltage of the grid-type unit to jump;

[0028] A short-circuit impedance determination module is used to determine the short-circuit impedance required by the grid-type unit in a voltage amplitude and phase jump test scenario based on the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0029] In some embodiments of the present application, the equivalent potential is the potential of the three-phase ideal voltage source connected to the power grid;

[0030] The internal impedance is the equivalent impedance from the position corresponding to the internal potential to the machine end;

[0031] The system impedance is the equivalent impedance from the machine end to the access power grid.

[0032] In some embodiments of the present application, a test device for voltage amplitude and phase jump of a grid-type unit further includes:

[0033] The first internal impedance determination module is used to determine the internal impedance according to the box transformer impedance, filter impedance and the virtual impedance of the grid-type unit when there is no voltage and current inner loop control of the grid-type unit and there is virtual impedance.

[0034] In some embodiments of the present application, a test device for voltage amplitude and phase jump of a grid-type unit further includes:

[0035] The second internal impedance determination module is used to determine the internal impedance according to the box transformer impedance and filter impedance of the grid-type unit when the grid-type unit does not have voltage and current inner loop control and virtual impedance.

[0036] In some embodiments of the present application, a test device for voltage amplitude and phase jump of a grid-type unit further includes:

[0037] The third internal impedance determination module is used to determine the internal impedance according to the box transformer impedance and the virtual impedance of the grid-type unit when the grid-type unit has voltage and current inner loop control and virtual impedance.

[0038] In some embodiments of the present application, a test device for voltage amplitude and phase jump of a grid-type unit further includes:

[0039] The fourth internal impedance determination module is used to determine the internal impedance according to the impedance of the box transformer of the grid-type unit when the grid-type unit has voltage and current inner loop control and does not have virtual impedance.

[0040] In some embodiments of the present application, the short-circuit impedance determination module includes:

[0041] a jump amount determining unit, configured to determine voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase;

[0042] A curve cluster generating unit, configured to generate a curve cluster of the voltage amplitude jump amount and the voltage phase jump amount as the ground impedance changes according to the voltage amplitude jump amount and the voltage phase jump amount corresponding to the plurality of ground impedances;

[0043] A short-circuit impedance determination unit is used to determine the short-circuit impedance according to the curve cluster.

[0044] In a third aspect, the present invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of a method for testing voltage amplitude and phase jump of a grid-type unit.

[0045] In a fourth aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the processor implements the steps of a method for testing the voltage amplitude and phase jump of a grid-type unit.

[0046] In a fifth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for testing voltage amplitude and phase jump of a grid-type unit.

[0047] From the above description, it can be seen that an embodiment of the present invention provides a testing method and device for the voltage amplitude and phase jump of a grid-type unit. The corresponding testing method for the voltage amplitude and phase jump of a grid-type unit includes: first, determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-type unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance; then, determining the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump; finally, determining the short-circuit impedance required for the grid-type unit in the voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0048] In summary, the present invention proposes a testing method suitable for the voltage phase and amplitude jump conditions of a grid-type unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 The flow chart of a method for testing voltage amplitude and phase jump of a grid-type unit in an embodiment of the present invention is as follows Figure 1 .

[0051] Figure 2 It is a schematic diagram of an equivalent system in which a grid-forming unit is connected to a large power grid in an embodiment of the present invention.

[0052] Figure 3 The flow chart of a method for testing voltage amplitude and phase jump of a grid-type unit in an embodiment of the present invention is as follows Figure 2 .

[0053] Figure 4 The flow chart of a method for testing voltage amplitude and phase jump of a grid-type unit in an embodiment of the present invention is as follows Figure 3 .

[0054] Figure 5The flow chart of a method for testing voltage amplitude and phase jump of a grid-type unit in an embodiment of the present invention is as follows Figure 4 .

[0055] Figure 6 The flow chart of a method for testing voltage amplitude and phase jump of a grid-type unit in an embodiment of the present invention is as follows Figure 5 .

[0056] Figure 7 It is a flowchart diagram of step 300 of a method for testing voltage amplitude and phase jump of a grid-type unit in an embodiment of the present invention.

[0057] Figure 8 It is a schematic diagram of phase angle jump after the ground impedance is put into use in a specific implementation manner of the present invention.

[0058] Fig. 9 It is a schematic diagram of voltage amplitude after grounding impedance is put into use in a specific implementation manner of the present invention.

[0059] Fig.10 It is a flow chart of a method for testing voltage amplitude and phase jump of a grid-type unit in a specific implementation manner of the present invention.

[0060] Fig.11 A block diagram of a test device for voltage amplitude and phase jump of a grid-type generator set in an embodiment of the present invention Figure 1 .

[0061] Fig.12 A block diagram of a device for testing voltage amplitude and phase jump of a grid-type generator set in an embodiment of the present invention Figure 2 .

[0062] Fig.13 A block diagram of a test device for voltage amplitude and phase jump of a grid-type generator set in an embodiment of the present invention Figure 3 .

[0063] Fig.14 A block diagram of a device for testing voltage amplitude and phase jump of a grid-type generator set in an embodiment of the present invention Figure 4 .

[0064] Fig.15 A block diagram of a device for testing voltage amplitude and phase jump of a grid-type generator set in an embodiment of the present invention Figure 5 .

[0065] Fig.16 is a block diagram of the short-circuit impedance determination module 30 in an embodiment of the present invention.

[0066] Fig.17 It is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0068] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may 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.

[0069] It should be noted that the terms "including" and "having" in the specification and claims of the present application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. In the absence of conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0070] The embodiment of the present invention provides a specific implementation method of a method for testing voltage amplitude and phase jump of a grid-type unit, see Figure 1 , the method comprising:

[0071] Step 100: determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-connected unit, the equivalent potential of the grid, the internal impedance and the system impedance;

[0072] Step 200: determining a second voltage amplitude and a second voltage phase after the voltage amplitude and phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump;

[0073] Step 300: Determine the short-circuit impedance required for the grid-type unit in a voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase.

[0074] From the above description, it can be seen that an embodiment of the present invention provides a test method for voltage amplitude and phase jump of a grid-type unit, including: first, determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-type unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance; then, determining the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump; finally, determining the short-circuit impedance required for the grid-type unit in the voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0075] The present invention proposes an equivalent system for connecting a grid-type unit to a large power grid, a method for calculating system impedance and internal impedance, a method for calculating phase jump and voltage amplitude under disturbance, and a method for guiding the selection of ground impedance under disturbance conditions using a cluster of curves showing phase angle and amplitude changes with impedance. This method is suitable for testing scenarios of response characteristics of grid-type new energy units under disturbance, including electromagnetic transient simulation, hardware-in-the-loop testing, and on-site physical testing.

[0076] In the current power grid, synchronous generator sets with autonomous voltage building capabilities are the main body to ensure the synchronous and stable operation of the power system. In recent years, a large number of new energy units have adopted a grid-following control method in which the phase-locked loop passively follows the grid voltage, and do not have the ability to actively support frequency and voltage. After its large-scale replacement of synchronous machines, the basis for maintaining the safe and stable frequency and voltage of the system has been weakened. In recent years, large-scale grid disconnection incidents of new energy have occurred in many places due to insufficient active frequency and voltage support capabilities. By improving the converter control method, the grid-building technology enables new energy units to have the ability to establish grid voltage and frequency, and can be connected to the grid as an equivalent voltage source, and realize active support functions such as inertia response, primary frequency regulation response, and rapid voltage regulation through appropriate control.

[0077] For step 100, the internal potential refers to the voltage generated internally by the grid-type unit when no external current is provided. In addition, it should be pointed out that the equivalent potential refers to the use of a single potential to replace the electric field effect of a complex circuit or multiple potential sources on a circuit in some cases. In other words, the equivalent potential is a simplified way to describe the movement of charges and energy conversion in a circuit using an imaginary potential value.

[0078] See also Figure 2It can be understood that the grounding impedance in step 200 is generated by the grounding resistor in the figure, and the grounding resistor cooperates with the connection or disconnection of the series switch S0 to cause the voltage amplitude and voltage phase of the inverter terminal voltage of the grid-type unit to jump, thereby performing the test in this scenario.

[0079] For step 300, specifically, the changes of the voltage amplitude and phase jump of the grid-type unit before and after the voltage amplitude and phase jump can be determined according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase. Each group of changes (voltage amplitude and phase jump) corresponds to a ground impedance, so that multiple voltage amplitudes and phase jumps corresponding to multiple ground impedances can be obtained, and then a curve cluster can be generated, and then reasonable test conditions can be set according to the response requirements for the disturbance characteristics of the converter in various standards or test procedures. This method is suitable for electromagnetic transient simulation, hardware-in-the-loop testing and on-site physical testing.

[0080] In some embodiments of the present application, the equivalent potential is the potential of the three-phase ideal voltage source connected to the power grid; the internal impedance is the equivalent impedance from the position corresponding to the internal potential to the machine end; and the system impedance is the equivalent impedance from the machine end to the access power grid.

[0081] Continue to see Figure 2 , the figure shows the equivalent system of the grid-forming unit connected to the large power grid, and the test method of the voltage amplitude and phase jump of the grid-forming unit proposed in the present invention is implemented based on this system. Among them:

[0082] Phase is the potential inside the grid-type unit, the phasor For the equivalent three-phase ideal voltage source connected to the power grid (large power grid), the phasor is the terminal voltage of the grid-forming unit, which can generally be considered to be on the high-voltage side of the box-type transformer (typical ratio is 690V / 35kV). In steady state, the grid-forming unit outputs active power to the large power grid as P 12 .

[0083] Z1 is the equivalent impedance from the internal potential of the grid-forming unit to the machine end, that is, the internal impedance; Z2 is the equivalent impedance from the grid-forming unit end to the large power grid, that is, the system impedance.

[0084] There is a grounding impedance Z0 of a series switch S0 at , and the input of this impedance can realize the phase and amplitude jump disturbance of the voltage at the machine end of the converter, and the specific size of the disturbance is determined by the value of this impedance.

[0085] In some embodiments of the present application, the system impedance in step 100 and step 200 can be obtained by obtaining the per-unit value of the system impedance Z2.

[0086] 1) For an ideal system or a typical test system, the per-unit value of Z2 can be set directly, such as 0.2pu.

[0087] 2) For small-scale simple systems, the impedance of transformers and lines at each voltage level can be reduced to The voltage level is calculated to obtain the respective per-unit values, and then the series-parallel combination is carried out according to the system structure to obtain the per-unit value of Z2.

[0088] 3) For large-scale systems, common power system electromechanical transient simulation software can generally be used to model the system and calculate the short-circuit ratio (SCR) at the bus where the grid-type unit is located. The per-unit value of Z2 is the reciprocal of the SCR.

[0089] In some embodiments of the present application, see Figure 3 , a method for testing voltage amplitude and phase jump of a grid-type unit, further comprising:

[0090] Step 400: When the grid-type unit does not have voltage and current inner loop control and has virtual impedance, the internal impedance is determined according to the box transformer impedance, filter impedance and the virtual impedance of the grid-type unit.

[0091] The internal impedance is calculated by calculating the per-unit value of the internal impedance Z1 of the grid-type unit. This per-unit value needs to be calculated separately according to the specific control method of the grid-type unit. Define the per-unit value of the impedance of the box-type transformer as Z T The filter impedance per unit value of the grid-type unit is Z f , the virtual impedance generated by the grid-type unit control is Z v .

[0092] For grid-type units without voltage and current inner loop control and with virtual impedance:

[0093] Z1=Z T +Z f +Z v (1)

[0094] In some embodiments of the present application, see Figure 4 , a method for testing voltage amplitude and phase jump of a grid-type unit, further comprising:

[0095] Step 500: When the grid-type unit does not have voltage and current inner loop control and virtual impedance, the internal impedance is determined according to the box transformer impedance and filter impedance of the grid-type unit.

[0096] For grid-type units without voltage and current inner loop control and virtual impedance:

[0097] Z1=Z T +Z f (1)

[0098] In some embodiments of the present application, see Figure 5 , a method for testing voltage amplitude and phase jump of a grid-type unit, further comprising:

[0099] Step 600: When the grid-type unit has voltage and current inner loop control and virtual impedance, the internal impedance is determined according to the box transformer impedance and the virtual impedance of the grid-type unit.

[0100] For grid-type units with voltage and current inner loop control and virtual impedance:

[0101] Z1=Z T +Z v (2)

[0102] In some embodiments of the present application, see Figure 6 , a method for testing voltage amplitude and phase jump of a grid-type unit, further comprising:

[0103] Step 700: When the grid-type unit has voltage and current inner loop control and does not have virtual impedance, the internal impedance is determined according to the impedance of the box transformer of the grid-type unit.

[0104] For grid-type units with voltage and current inner loop control and no virtual impedance:

[0105] Z1=Z T (3)

[0106] In some embodiments of the present application, see Figure 7 , step 300 comprises:

[0107] Step 301: determining voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase;

[0108] First, calculate the value before switch S0 is closed. Obviously there are:

[0109]

[0110] It can be solved as follows:

[0111]

[0112] The amplitude U0 and phase angle θ0 can be obtained by The amplitude and phase angle are expressed to calculate. The right sides of the equation are all known quantities, so it can be calculated directly.

[0113] Then calculate the value after switch S0 is closed Record it as See also Figure 2 , now there is an additional grounding branch Z0. According to Kirchhoff's current law:

[0114]

[0115] It can be solved as follows:

[0116]

[0117] The amplitude U f and phase angle θ f Can be The amplitude and phase angle are expressed to calculate.

[0118] When specified and After that, the right side of the equation is known, so the phasor can be calculated. In general, the specified large grid voltage is:

[0119]

[0120] Potential inside grid-type unit The amplitude U1 can generally be specified as 1. The phase angle θ1 can be specified directly or based on the disturbance Towards Output active power P 12 , back-calculated using the active power transfer equation:

[0121]

[0122] The above formula gives After that, the phasor can be further decomposed into amplitude U f and phase angle θ f , and then calculate the phase angle jump amount and voltage amplitude after the switch S0 is closed:

[0123] Phase angle jump variable = θ f –θ0;

[0124] Voltage amplitude = U f ;

[0125] Step 302: generating a curve cluster of the voltage amplitude jump amount and the voltage phase jump amount as the ground impedance changes according to the voltage amplitude jump amount and the voltage phase jump amount corresponding to the plurality of ground impedances;

[0126] Specifically, a cluster of curves of phase angle and amplitude changing with impedance is calculated. The following typical parameters are used as examples for illustration (the present invention is not limited to the specific values ​​of the parameters):

[0127] Suppose Z1=Z2=0+j0.1 pu, U1=U2=1, θ2=0, P 12 =1.

[0128] For Z0=R0+jX0, let R0=1e -4 ~1e 2 pu,X0 / R0=0.01,0.03,0.1,0.3,1,3.3,10,33,100. By calculating the phase angle jump and voltage amplitude, we can get the curve cluster of phase angle jump and voltage amplitude with impedance change under disturbance. The results are as follows: Figure 8 as well as Fig. 9 It should be noted that the specific values ​​of the above parameters are only indicative and not fixed parameters, and should be adjusted according to specific circumstances in actual application.

[0129] Step 303: Determine the short-circuit impedance according to the curve cluster.

[0130] Specifically, using Figure 8 as well as Fig. 9 The curve cluster can set reasonable test conditions according to the response requirements of the converter disturbance characteristics in various standards or test procedures. This method is suitable for electromagnetic transient simulation, hardware-in-the-loop testing and on-site physical testing.

[0131] From the above description, it can be seen that an embodiment of the present invention provides a test method for voltage amplitude and phase jump of a grid-type unit, including: first, determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-type unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance; then, determining the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump; finally, determining the short-circuit impedance required for the grid-type unit in the voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0132] The present invention proposes an equivalent system for connecting a grid-type unit to a large power grid, a method for calculating system impedance and internal impedance, a method for calculating phase jump and voltage amplitude under disturbance, and a method for guiding the selection of ground impedance under disturbance conditions using a cluster of curves showing phase angle and amplitude changes with impedance. This method is suitable for testing scenarios of response characteristics of grid-type new energy units under disturbance, including electromagnetic transient simulation, hardware-in-the-loop testing, and on-site physical testing.

[0133] To further illustrate the solution, the present invention also provides a specific implementation method of a method for testing the voltage amplitude and phase jump of a grid-type unit, see Fig.10, the method includes the following contents:

[0134] S1: Determine the voltage amplitude, the first voltage amplitude and the first voltage phase before the phase jump according to the internal potential of the grid-forming unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance;

[0135] S2: Determine the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-forming unit to jump;

[0136] S3: determining voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase;

[0137] S4: generating a cluster of curves of the voltage amplitude jump variable and the voltage phase jump variable changing with the grounding impedance according to the voltage amplitude jump variables and the voltage phase jump variables corresponding to the multiple grounding impedances;

[0138] S5: Determine the short-circuit impedance based on the curve cluster.

[0139] Here, step S5 is explained with reference to two specific embodiments.

[0140] 1) A certain test procedure requires that the grid-type unit has low voltage ride-through capability when the terminal voltage drops to 20% and the short-circuit branch impedance ratio is X / R=10. Figure 8 On the X / R=10 curve in the figure, find the point where the voltage amplitude after disturbance is 0.2pu, and get the resistance R0=0.001256pu in the short-circuit impedance, and then calculate the reactance X0=10R0 in the short-circuit impedance. Using the obtained short-circuit impedance, the test work of the grid-type unit under the above requirements can be realized.

[0141] 2) A certain standard requires that when the voltage at the machine end drops to 20% and the phase angle at the machine end lags by 30 degrees, the grid-connected unit has the ability to operate stably without disconnecting from the grid. Fig. 9 Draw a horizontal line with voltage = 0.2pu in the figure, intersect with each curve to get a series of horizontal coordinates R0, and then Figure 8 Find the phase angle jump value corresponding to the horizontal axis. Figure 8 as well as Fig. 9 The curve clusters used for display cannot be drawn too densely, so the curve closest to the requirement is X / R = 1 (phase angle lag 36.8 degrees). In fact, in practical applications, it is easy to get R0 = 0.00737pu, X / R = 1.4, which meets the above standard requirements. Using the obtained short-circuit impedance, the test work of the grid-type unit under the above requirements can be realized.

[0142] From the above description, it can be seen that the specific application example of the present invention provides a test method for the voltage amplitude and phase jump of a grid-type unit, including: first, determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-type unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance; then, determining the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump; finally, determining the short-circuit impedance required for the grid-type unit in the voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0143] The present invention proposes an equivalent system for connecting a grid-type unit to a large power grid, a method for calculating system impedance and internal impedance, a method for calculating phase jump and voltage amplitude under disturbance, and a method for guiding the selection of ground impedance under disturbance conditions using a cluster of curves showing phase angle and amplitude changes with impedance. This method is suitable for testing scenarios of response characteristics of grid-type new energy units under disturbance, including electromagnetic transient simulation, hardware-in-the-loop testing, and on-site physical testing.

[0144] Based on the same inventive concept, the embodiments of the present application also provide a test device for the voltage amplitude and phase jump of a meshed unit, which can be used to implement the method described in the above embodiments, such as the following embodiments. Since the principle of solving the problem by the test device for the voltage amplitude and phase jump of a meshed unit is similar to the test method for the voltage amplitude and phase jump of a meshed unit, the implementation of the test device for the voltage amplitude and phase jump of a meshed unit can refer to the implementation of the test method for the voltage amplitude and phase jump of a meshed unit, and the repeated parts will not be repeated. As used below, the term "unit" or "module" can be a combination of software and / or hardware that implements a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0145] The embodiment of the present invention provides a specific implementation of a test device for voltage amplitude and phase jump of a grid-type generator set, which can realize a test method for voltage amplitude and phase jump of a grid-type generator set. Fig.11 A test device for voltage amplitude and phase jump of a grid-type unit specifically includes the following contents:

[0146] A pre-jump value determination module 10 is used to determine the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-type unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance;

[0147] The post-jump value determination module 20 is used to determine the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the ground impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the ground impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump;

[0148] The short-circuit impedance determination module 30 is used to determine the short-circuit impedance required by the grid-type unit in the voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0149] In some embodiments of the present application, the equivalent potential is the potential of the three-phase ideal voltage source connected to the power grid;

[0150] The internal impedance is the equivalent impedance from the position corresponding to the internal potential to the machine end;

[0151] The system impedance is the equivalent impedance from the machine end to the access power grid.

[0152] In some embodiments of the present application, see Fig.12 , a test device for voltage amplitude and phase jump of grid-forming units, further comprising:

[0153] The first internal impedance determination module 40 is used to determine the internal impedance according to the box transformer impedance, filter impedance and the virtual impedance of the grid-type unit when there is no voltage and current inner loop control of the grid-type unit and there is a virtual impedance.

[0154] In some embodiments of the present application, see Fig.13 , a test device for voltage amplitude and phase jump of grid-forming units, further comprising:

[0155] The second internal impedance determination module 50 is used to determine the internal impedance according to the box transformer impedance and filter impedance of the grid-type unit when the grid-type unit does not have voltage and current inner loop control and virtual impedance.

[0156] In some embodiments of the present application, see Fig.14 , a test device for voltage amplitude and phase jump of grid-forming units, further comprising:

[0157] The third internal impedance determination module 60 is used to determine the internal impedance according to the box transformer impedance and the virtual impedance of the grid-type unit when the grid-type unit has voltage and current inner loop control and virtual impedance.

[0158] In some embodiments of the present application, see Fig.15, a test device for voltage amplitude and phase jump of grid-forming units, further comprising:

[0159] The fourth internal impedance determination module 70 is used to determine the internal impedance according to the impedance of the box transformer of the grid-type unit when the grid-type unit has voltage and current inner loop control and does not have virtual impedance.

[0160] In some embodiments of the present application, see Fig.16 , the short-circuit impedance determination module 30 includes:

[0161] a jump amount determining unit 30a, configured to determine voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase;

[0162] A curve cluster generating unit 30b, configured to generate a curve cluster of the voltage amplitude jump amount and the voltage phase jump amount as the ground impedance changes according to the voltage amplitude jump amount and the voltage phase jump amount corresponding to the plurality of ground impedances;

[0163] The short-circuit impedance determination unit 30c is used to determine the short-circuit impedance according to the curve cluster.

[0164] From the above description, it can be seen that an embodiment of the present invention provides a test device for voltage amplitude and phase jump of a grid-type unit, including: a pre-jump value determination module, which is used to determine the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-type unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance; a post-jump value determination module, which is used to determine the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump; a short-circuit impedance determination module, which is used to determine the short-circuit impedance required for the grid-type unit in the voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

[0165] The test device for the voltage amplitude and phase jump of the grid-type unit proposed in the embodiment of the present invention discloses the equivalent system of the grid-type unit connected to the large power grid, the calculation method of the system impedance and the internal impedance, the calculation method of the phase jump and the voltage amplitude under disturbance, and the method of guiding the selection of the grounding impedance under disturbance conditions by using a cluster of curves of phase angle and amplitude changing with impedance. This method is suitable for the test scenarios of the response characteristics of the grid-type new energy unit under disturbance, including electromagnetic transient simulation, hardware-in-the-loop test and on-site physical test.

[0166] The embodiments of the present application also provide a specific implementation of an electronic device capable of implementing all steps in the method for testing the voltage amplitude and phase jump of the grid-type generator set in the above embodiment, see Fig.17 , electronic equipment specifically includes the following:

[0167] Processor (processor) 1201, memory (memory) 1202, communication interface (CommunicationsInterface) 1203 and bus 1204;

[0168] The processor 1201, the memory 1202, and the communication interface 1203 communicate with each other through the bus 1204; the communication interface 1203 is used to realize information transmission between the server device and the client device and other related devices;

[0169] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, all the steps in the test method for the voltage amplitude and phase jump of the grid-type unit in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0170] Step 100: determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-connected unit, the equivalent potential of the grid, the internal impedance and the system impedance;

[0171] Step 200: determining a second voltage amplitude and a second voltage phase after the voltage amplitude and phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump;

[0172] Step 300: Determine the short-circuit impedance required for the grid-type unit in a voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase.

[0173] The embodiments of the present application also provide a computer-readable storage medium capable of implementing all the steps in the method for testing the voltage amplitude and phase jump of a grid-type unit in the above embodiment. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, all the steps in the method for testing the voltage amplitude and phase jump of a grid-type unit in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0174] Step 100: determining the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-connected unit, the equivalent potential of the grid, the internal impedance and the system impedance;

[0175] Step 200: determining a second voltage amplitude and a second voltage phase after the voltage amplitude and phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump;

[0176] Step 300: Determine the short-circuit impedance required for the grid-type unit in a voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase.

[0177] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the hardware + program embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0178] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0179] Although the present application provides method operation steps such as embodiments or flow charts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order of the method shown in the embodiments or the drawings or in parallel (for example, in a parallel processor or multi-threaded processing environment).

[0180] For the convenience of description, the above devices are described in various modules according to their functions. Of course, when implementing the embodiments of this specification, the functions of each module can be implemented in the same or more software and / or hardware, or the module implementing the same function can be implemented by a combination of multiple sub-modules or sub-units. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0181] Those skilled in the art also know that, in addition to implementing the controller in a purely computer-readable program code, the controller can be made to implement the same function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, such a controller can be considered as a hardware component, and the devices for implementing various functions included therein can also be considered as structures within the hardware component. Or even, the devices for implementing various functions can be considered as both software modules for implementing the method and structures within the hardware component.

[0182] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0183] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0184] The present specification embodiments may be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present specification embodiments may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules may be located in local and remote computer storage media, including storage devices.

[0185] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of this specification. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of contradiction, a person skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0186] The above is only an example of the embodiment of the present specification and is not intended to limit the embodiment of the present specification. For those skilled in the art, the embodiment of the present specification may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiment of the present specification shall be included in the scope of the claims of the embodiment of the present specification.

Claims

1. A method for testing voltage amplitude and phase jump of a grid-type unit, characterized in that: include: Determine the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-forming unit, the equivalent potential of the grid, the internal impedance and the system impedance; Determine the second voltage amplitude and the second voltage phase after the voltage amplitude and the phase jump according to the grounding impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the grounding impedance is used to cause the voltage amplitude and the voltage phase of the converter terminal voltage of the grid-type unit to jump; The short-circuit impedance required for the grid-type unit in a voltage amplitude and phase jump test scenario is determined according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase.

2. The testing method according to claim 1, characterized in that: The equivalent potential is the potential of the three-phase ideal voltage source connected to the power grid; The internal impedance is the equivalent impedance from the position corresponding to the internal potential to the machine end; The system impedance is the equivalent impedance from the machine end to the access power grid.

3. The testing method according to claim 1, characterized in that: Also includes: When the grid-type unit does not have voltage and current inner loop control and has virtual impedance, the internal impedance is determined according to the box transformer impedance, filter impedance and the virtual impedance of the grid-type unit.

4. The testing method according to claim 1, characterized in that: Also includes: When the grid-type unit does not have voltage and current inner loop control and virtual impedance, the internal impedance is determined according to the box transformer impedance and filter impedance of the grid-type unit.

5. The testing method according to claim 1, characterized in that: Also includes: When the grid-type generator set has voltage and current inner loop control and virtual impedance, the internal impedance is determined according to the box transformer impedance and the virtual impedance of the grid-type generator set.

6. The testing method according to claim 1, characterized in that: Also includes: When the grid-type generator set has voltage and current inner loop control and does not have virtual impedance, the internal impedance is determined according to the impedance of the box-type transformer of the grid-type generator set.

7. The testing method according to any one of claims 1 to 6, characterized in that: Determining the short-circuit impedance required by the grid-type unit in a voltage amplitude and phase jump test scenario according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase includes: Determine voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase; Generating a cluster of curves of the voltage amplitude jump amount and the voltage phase jump amount as the ground impedance changes according to the voltage amplitude jump amounts and the voltage phase jump amounts corresponding to the multiple ground impedances; The short-circuit impedance is determined based on the family of curves.

8. A test device for voltage amplitude and phase jump of a grid-type unit, characterized in that: include: A pre-jump value determination module is used to determine the first voltage amplitude and the first voltage phase before the voltage amplitude and the phase jump according to the internal potential of the grid-forming unit, the equivalent potential of the grid-connected unit, the internal impedance and the system impedance; A post-jump value determination module, used to determine the second voltage amplitude and second voltage phase after the voltage amplitude and phase jump according to the ground impedance, the internal potential, the equivalent potential, the internal impedance and the system impedance; wherein the ground impedance is used to cause the voltage amplitude and voltage phase of the converter terminal voltage of the grid-type unit to jump; A short-circuit impedance determination module is used to determine the short-circuit impedance required by the grid-type unit in a voltage amplitude and phase jump test scenario based on the first voltage amplitude, the second voltage amplitude, the first voltage phase and the second voltage phase.

9. The testing device according to claim 8, characterized in that: The equivalent potential is the potential of the three-phase ideal voltage source connected to the power grid; The internal impedance is the equivalent impedance from the position corresponding to the internal potential to the machine end; The system impedance is the equivalent impedance from the machine end to the access power grid.

10. The testing device according to claim 8, characterized in that: Also includes: The first internal impedance determination module is used to determine the internal impedance according to the box transformer impedance, filter impedance and the virtual impedance of the grid-type unit when there is no voltage and current inner loop control of the grid-type unit and there is virtual impedance.

11. The testing device according to claim 8, characterized in that: Also includes: The second internal impedance determination module is used to determine the internal impedance according to the box transformer impedance and filter impedance of the grid-type unit when the grid-type unit does not have voltage and current inner loop control and virtual impedance.

12. The testing device according to claim 8, characterized in that: Also includes: The third internal impedance determination module is used to determine the internal impedance according to the box transformer impedance and the virtual impedance of the grid-type unit when the grid-type unit has voltage and current inner loop control and virtual impedance.

13. The testing device according to claim 8, characterized in that: Also includes: The fourth internal impedance determination module is used to determine the internal impedance according to the impedance of the box transformer of the grid-type unit when the grid-type unit has voltage and current inner loop control and does not have virtual impedance.

14. The testing device according to any one of claims 8 to 13, characterized in that: The short-circuit impedance determination module comprises: a jump amount determining unit, configured to determine voltage amplitude jump amounts and voltage phase jump amounts corresponding to a plurality of ground impedances according to the first voltage amplitude, the second voltage amplitude, the first voltage phase, and the second voltage phase; A curve cluster generating unit, configured to generate a curve cluster of the voltage amplitude jump amount and the voltage phase jump amount as the ground impedance changes according to the voltage amplitude jump amount and the voltage phase jump amount corresponding to the plurality of ground impedances; A short-circuit impedance determination unit is used to determine the short-circuit impedance according to the curve cluster.

15. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the method for testing the voltage amplitude and phase jump of a grid-type unit as described in any one of claims 1 to 7 are implemented.

16. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method for testing the voltage amplitude and phase jump of a grid-type unit as described in any one of claims 1 to 7 are implemented.

17. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for testing the voltage amplitude and phase jump of a grid-type unit described in any one of claims 1 to 7 are implemented.

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