A boundary condition and multi-dimensional margin calculation method for new energy repeated crossing instability

Abstract

The application discloses a boundary condition and a multi-dimension margin calculation method for new energy repeated crossing instability, and first establishes a new energy repeated crossing boundary expression according to unit and new energy parameters, and then calculates the machine side margin and the network side margin under the repeated crossing boundary based on the new energy repeated crossing boundary expression. The application deduces the repeated crossing boundary of new energy crossing control, obtains the machine side margin and the network side margin under different boundaries, and respectively deduces the expressions of the maximum power and the line impedance for the repeated crossing boundary, and calculates different margins, so that the application can be suitable for the calculation of new transient instability phenomena dominated by new energy crossing control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, and more particularly, to a boundary condition and multi-dimensional margin calculation method for new energy repeated ride-through instability. BACKGROUND

[0002] With the continuous increase of new energy installed capacity, the transient voltage stability of power systems has been significantly affected. The instability phenomenon of new transient voltage problems dominated by new energy low voltage ride-through control is significantly different from conventional power systems. During the transient period, various new energies exhibit different low voltage ride-through and recovery characteristics, and their active and reactive power fluctuation rules are significantly different from conventional power sources. The new transient instability phenomenon dominated by new energy ride-through control includes "continuous low voltage ride-through" and "repeated low voltage ride-through".

[0003] Under the boundary condition of repeated low voltage ride-through, the margin of the new energy system is subject to new boundary constraints. At present, the model based on the conventional boundary takes the nose point as the boundary. With the application of low voltage ride-through technology, the boundary constraints and margins of the new energy system will further change. In order to consider the new transient voltage instability phenomenon of power systems dominated by new energy ride-through control, it is necessary to establish a repeated ride-through boundary suitable for new energy ride-through control. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a boundary condition and multi-dimensional margin calculation method for new energy repeated ride-through instability, which derives the repeated ride-through boundary of new energy ride-through control and obtains the comparison of machine side margin and grid side margin under different boundaries.

[0005] According to one aspect of the present application, a boundary condition and multi-dimensional margin calculation method for new energy repeated ride-through instability is provided, comprising:

[0006] Based on the parameters of the unit and the new energy, a new energy repeated ride-through boundary expression is established; wherein the new energy repeated ride-through boundary expression is:

[0007]

[0008] Based on the new energy repeated ride-through boundary expression, the machine side margin M P,R and the grid side margin M Z,R under the repeated ride-through boundary are calculated; wherein the calculation formula of the machine side margin M P,R and the grid side margin M Z,R under the repeated ride-through boundary is:

[0009]

[0010]

[0011] A=[(SKP1 V L +K P2 I P0 +SI Pset ) 2 +(SI Qset ) 2 V L 2

[0012] B = [(SK P1 V L +K P2 I P0 +SI Pset cosθ+SI Qset sinθ]V L 3 ;

[0013] C = -E 2 V L 2 +V L 4

[0014] In the formula, Z th V represents the line impedance amplitude under the conventional boundary conditions of the equivalent model of the new energy power system. L For the low-voltage ride-through threshold of new energy sources, P max Let θ be the maximum active power output of the equivalent model of the new energy power system, θ be the line impedance phase angle of the equivalent model of the new energy power system, S be the rated capacity of the new energy, and I be the maximum active power output of the equivalent model of the new energy power system. Qset The reactive current is set for the renewable energy source, E is the voltage at the point of common coupling, P is the active power output of the renewable energy source under the current operating state of the equivalent model of the renewable energy power system, Z is the line impedance amplitude under the current operating state of the equivalent model of the renewable energy power system, and K is the reactive current set for the renewable energy source. P1 K is the first control parameter for the active current of new energy sources. P2 I is the second control parameter for the active current of the new energy source. P0 For the active current of new energy sources before they enter low-voltage ride-through, I Pset Active current set for new energy sources.

[0015] Optionally, establishing the expression for repeated boundary crossings of the new energy source based on the unit and new energy parameters includes:

[0016] Acquire parameters of each unit and load within the system, including the point of common coupling voltage E and the first control parameter K of the active current of the new energy source. P1 Second control parameter K P2 Control parameter K of reactive current of new energy Q1 The voltage amplitude V at the grid connection point of new energy equipment t, the voltage phase angle α of the grid-connected point of the new energy equipment;

[0017] According to the obtained parameters, the conventional boundary expression of the unit and the new energy parameters is established, and the calculation formula is as follows:

[0018]

[0019]

[0020] Eliminate the angle α, and the conventional boundary expression is simplified as:

[0021]

[0022] The expression of the current characteristics of the new energy during low voltage ride through is determined as:

[0023] I P = SK P1 V t + K P2 I P0 + SI Pset ;

[0024] I Q = SK Q1 (V L -V t ) + SI Qset ;

[0025] The expression of the new energy power flow characteristics is determined as:

[0026]

[0027] During low voltage ride through, the expression of the new energy current characteristics is substituted into the expression of the new energy power flow characteristics, and the following is obtained:

[0028]

[0029] The analytical expression Z of the POC point voltage phase angle is obtained by solving as: th

[0030]

[0031] The expression of the new energy current characteristics and the expression of the new energy power flow characteristics are substituted into the simplified conventional boundary expression, and the following is obtained:

[0032]

[0033] When V t = V L , the new energy repeatedly ride through boundary expression of the new energy running under the repeatedly ride through boundary is:

[0034] ​

[0035] In the formula, P is the active power output of the new energy power system equivalent model under the current operating state, Q is the reactive power output of the new energy power system equivalent model under the current operating state, V is the voltage amplitude of the grid-connected point of the new energy equipment, θ is the phase angle of the line impedance of the new energy power system equivalent model, E is the voltage of the point of common coupling, α is the phase angle of the grid-connected point voltage of the new energy equipment, Z is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V is the voltage amplitude of the grid-connected point of the new energy equipment, V is the low-voltage ride-through judgment threshold of the new energy, I is the active current of the new energy under the current operating state, I is the reactive current of the new energy under the current operating state, S is the rated capacity of the new energy, I is the active current of the new energy before entering the low-voltage ride-through, V is the low-voltage ride-through judgment threshold of the new energy, I is the set active current of the new energy, I is the set reactive current of the new energy, P is the active power output of the new energy, P is the active power consumption of the load, Q is the reactive power output of the new energy, P is the maximum active power output of the new energy power system equivalent model, K is the first control parameter of the active current of the new energy, K is the second control parameter of the active current of the new energy, and K is the control parameter of the reactive current of the new energy. t th L L P Q P0 L Pset Qset R R P t L R R Q t max P1 P2 Q1

[0036] Optionally, the new energy repeated ride-through boundary expression is based on the repeated ride-through boundary expression, and the machine-side margin M and the grid-side margin M are calculated under the repeated ride-through boundary. P,R Z,R

[0037] The machine-side margin M and the grid-side margin M are defined as: P z

[0038]

[0039] ​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0040] According to the new energy repeated crossing boundary expression, when P max = P R = I P * V t , the expression of Z th is obtained as follows:

[0041]

[0042]

[0043] According to the new energy repeated crossing boundary expression, the expression of Z th , the defined machine side margin M P and the grid side margin M z , the calculation formula of the machine side margin M P,R and the grid side margin M Z,R under the repeated crossing boundary is obtained:

[0044]

[0045]

[0046]

[0047] According to the calculation formula, the machine side margin M P,R and the grid side margin M Z,R under the repeated crossing boundary are determined.

[0048] In the formula, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I Qset is the set reactive current of the new energy, E is the point of common coupling voltage, P is the active power of the new energy power system equivalent model under the current operating state, Z is the line impedance amplitude of the new energy power system equivalent model under the current operating state, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current of the new energy before entering the low voltage ride through, I Pset is the set active current of the new energy.

[0049] Optionally, the method further comprises:

[0050] According to the unit and new energy parameters, a new energy conventional boundary expression is established, wherein the new energy conventional boundary expression is:

[0051] E 2 -2P max (1-cosθ)Z th =0;

[0052] Based on the new energy conventional boundary expression, the machine-side margin M P,N and the grid-side margin M Z,N under the conventional boundary are calculated; wherein the calculation formula of the machine-side margin M P,N and the grid-side margin M Z,N under the conventional boundary is:

[0053]

[0054]

[0055] In the formula, E is the voltage of the point of common coupling, P max is the maximum active power of the equivalent model of the new energy power system, θ is the phase angle of the line impedance of the equivalent model of the new energy power system, Z th is the line impedance amplitude of the equivalent model of the new energy power system under the conventional boundary, Z is the line impedance amplitude of the equivalent model of the new energy power system under the current operating state, and P is the active power of the new energy of the equivalent model of the new energy power system under the current operating state.

[0056] The machine-side margin M P,R and the grid-side margin M Z,R under the repeated crossing boundary are compared with the machine-side margin M P,N and the grid-side margin M Z,N under the conventional boundary.

[0057] According to the comparison result, the calculation accuracy of the machine-side margin M P,R and the grid-side margin M Z,R under the repeated crossing boundary is evaluated.

[0058] Optionally, the establishing of the new energy conventional boundary expression according to the unit and new energy parameters comprises:

[0059] The parameters of each unit and the load parameters in the system are obtained, including the voltage E of the point of common coupling, the voltage amplitude V t of the point of common coupling of the new energy equipment, and the phase angle α of the voltage of the point of common coupling of the new energy equipment.

[0060] According to the obtained parameters, the conventional boundary expression of the unit and the new energy parameters is established, and the calculation formula is as follows:

[0061]

[0062]

[0063] The conventional boundary expression is simplified as:

[0064]

[0065] When the new energy is constant power output, Q = 0, the conventional boundary expression is further simplified as:

[0066]

[0067] Then V t The two solutions of V

[0068]

[0069] When , V t has a repeated solution, V t The repeated solution of V

[0070]

[0071] That is, the critical voltage value is

[0072]

[0073] Substitute the critical voltage value into the repeated solution of V t , the maximum active power P max at the critical voltage value is obtained. th The expression of the line impedance amplitude Z

[0074]

[0075] Solving Z th , we get:

[0076]

[0077] Based on the repeated solution of V t , we get:

[0078]

[0079] Since P max is greater than 0, Z th is greater than 0, and the negative solution in the expression is discarded, that is:

[0080]

[0081] When , the expression of Z th , the line impedance amplitude and the maximum active power corresponding to the nose point of the P-V curve is obtained.

[0082]

[0083] The expression of the new energy operation under the conventional boundary is:

[0084] E 2 -2P max (1-cosθ)Z th = 0;

[0085] In the formula, P max is the maximum active power of the equivalent model of the new energy power system, Z th,max is the maximum line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, V L is the low voltage ride through judgment threshold of the new energy, P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system, Q is the reactive power of the new energy under the current operating state of the equivalent model of the new energy power system, V t is the voltage amplitude of the grid-connected point of the new energy device, θ is the line impedance phase angle of the equivalent model of the new energy power system, E is the point of common coupling voltage, Z th is the line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, and Z is the line impedance amplitude under the current operating state of the equivalent model of the new energy power system.

[0086] Optionally, the new energy conventional boundary expression is used to calculate the machine side margin M P,N and the grid side margin M Z,N , including:

[0087] The machine side margin M P and the grid side margin M z are defined as:

[0088]

[0089]

[0090] According to the new energy conventional boundary expression, the defined machine side margin M P and the grid side margin M z , the calculation formula of the machine side margin M P,N and the grid side margin M Z,N under the conventional boundary is obtained:

[0091]

[0092]

[0093] In the formula, E is the point of common coupling voltage, P maxis the maximum active power of the equivalent model of the new energy power system, is the phase angle of the line impedance of the equivalent model of the new energy power system, Z th is the line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, Z is the line impedance amplitude under the current operating state of the equivalent model of the new energy power system, P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system.

[0094] According to another aspect of the present application, a device for calculating the boundary condition and multi-dimensional margin of repeated crossing of new energy instability is provided, comprising:

[0095] An expression establishing module is configured to establish a new energy repeated crossing boundary expression according to the parameters of the unit and the new energy, wherein the new energy repeated crossing boundary expression is:

[0096]

[0097] A multi-dimensional margin calculating module is configured to calculate the machine-side margin M P,R and the grid-side margin M Z,R under the repeated crossing boundary based on the new energy repeated crossing boundary expression, wherein the calculation formula of the machine-side margin M P,R and the grid-side margin M Z,R under the repeated crossing boundary is:

[0098]

[0099]

[0100]

[0101] In the formula, Z th is the line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, V L is the low-voltage ride-through judgment threshold of the new energy, P max is the maximum active power of the equivalent model of the new energy power system, is the phase angle of the line impedance of the equivalent model of the new energy power system, S is the rated capacity of the new energy, I Qset is the reactive current set by the new energy, E is the voltage of the point of common coupling, P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system, Z is the line impedance amplitude under the current operating state of the equivalent model of the new energy power system, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current before the new energy enters the low-voltage ride-through, I Pset is the active current set by the new energy.

[0102] According to still another aspect of the present application, there is provided a computer readable storage medium storing a computer program for performing the method according to any one of the preceding aspects of the present application.

[0103] According to still another aspect of the present application, there is provided an electronic device comprising: a processor; a memory for storing instructions executable by the processor; and the processor configured to read the executable instructions from the memory and execute the instructions to implement the method according to any one of the preceding aspects of the present application.

[0104] The present application firstly establishes a new energy repeated crossing boundary expression according to the unit and new energy parameters, and then calculates the machine side margin and network side margin under the repeated crossing boundary based on the new energy repeated crossing boundary expression. The present application derives the repeated crossing boundary of the new energy crossing control, obtains the machine side margin and network side margin under different boundaries, and respectively derives the expressions of the maximum power and line impedance for the repeated crossing boundary, and calculates different margins, so as to be applicable to the calculation of the new type of transient instability phenomenon dominated by the new energy crossing control. BRIEF DESCRIPTION OF DRAWINGS

[0105] The exemplary embodiments of the present application can be more fully understood with reference to the following drawings:

[0106] Figure 1 is a flowchart of the boundary condition of the new energy repeated crossing instability and the multi-dimensional margin calculation in the embodiment of the present application;

[0107] Figure 2 is a comparison diagram of the new energy maximum power and line impedance under the conventional boundary and the repeated crossing boundary in the embodiment of the present application;

[0108] Figure 3 is a margin comparison diagram of the new energy conventional boundary and the repeated crossing boundary when θ=90° in the embodiment of the present application;

[0109] Figure 4 is a structure diagram of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0110] The embodiments of the present application will be described in detail below, and when the following description refers to the accompanying drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0111] It should be understood that in the description of all embodiments of the present application, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can be explicitly or implicitly included one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0112] Figure 1 The flowchart of the boundary condition and multi-dimensional margin calculation method for repeated crossing instability of new energy provided by the present application is shown. As shown in Figure 1 The boundary condition and multi-dimensional margin calculation method for repeated crossing instability of new energy, comprising:

[0113] Step S101: According to the unit and new energy parameters, the new energy repeated crossing boundary expression is established; wherein the new energy repeated crossing boundary expression is:

[0114]

[0115] Step S102: Based on the new energy repeated crossing boundary expression, the machine side margin M P,R and the network side margin M Z,R under the repeated crossing boundary are calculated; wherein the calculation formula of the machine side margin M P,R and the network side margin M Z,R under the repeated crossing boundary is:

[0116]

[0117]

[0118]

[0119] In the formula, Z th is the line impedance amplitude under the conventional boundary of the new energy power system equivalent model, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I Qset is the reactive current set by the new energy, E is the point of common coupling voltage, P is the active power of the new energy power system equivalent model under the current operating state, Z is the line impedance amplitude of the new energy power system equivalent model under the current operating state, K P1 is the first control parameter of the new energy active current, K P2 is the second control parameter of the new energy active current, I P0I Pset is the active current of the new energy before low voltage ride through.

[0120] Optionally, the step of establishing the new energy repetitive ride through boundary expression according to the parameters of the units and the new energy comprises:

[0121] Obtaining parameters of each unit and load in the system, including the voltage E of the point of common coupling, the first control parameter K P1 and the second control parameter K P2 of the active current of the new energy, the control parameter K Q1 of the reactive current of the new energy, the voltage amplitude V t of the point of common coupling of the new energy device, and the phase angle α of the point of common coupling of the new energy device.

[0122] According to the obtained parameters, a conventional boundary expression is established for the parameters of the units and the new energy, and the calculation formula is as follows:

[0123]

[0124]

[0125] After eliminating the angle α, the conventional boundary expression is simplified as:

[0126]

[0127] The expression of the current characteristics of the new energy during low voltage ride through is determined as:

[0128] I P = SK P1 V t + K P2 I P0 + SI Pset ;

[0129] I Q = SK Q1 (V L -V t ) + SI Qset ;

[0130] The expression of the power flow characteristics of the new energy is determined as:

[0131]

[0132] During low voltage ride through, the expression of the current characteristics of the new energy is substituted into the expression of the power flow characteristics of the new energy, and the following is obtained:

[0133]

[0134] The analytical expression Z thFor:

[0135]

[0136] Substitute the expression of the new energy current characteristic and the expression of the new energy power flow characteristic into the simplified conventional boundary expression to obtain:

[0137]

[0138] When V t = V L , the new energy repeatedly traverses the boundary, and the new energy repeatedly traverses the boundary expression under the repeatedly traversing boundary is:

[0139]

[0140] In the formula, P is the active power output of the new energy power system equivalent model under the current operating state, Q is the reactive power output of the new energy power system equivalent model under the current operating state, V t is the voltage amplitude of the grid-connected point of the new energy device, θ is the phase angle of the line impedance of the new energy power system equivalent model, E is the point of common coupling voltage, α is the phase angle of the grid-connected point voltage of the new energy device, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low-voltage ride-through judgment threshold, V L is the new energy low-voltage ride-through judgment threshold, I P is the active current under the current operating state of the new energy, I Q is the reactive current under the current operating state of the new energy, S is the rated capacity of the new energy, I P0 is the active current before the new energy enters the low-voltage ride-through, V L is the new energy low-voltage ride-through judgment threshold, I Pset is the set active current of the new energy, I Qset is the set reactive current of the new energy, P R is the active power output of the new energy, P R = I P * V t , P L is the active power consumption of the load, Q R is the reactive power output of the new energy, Q R = I Q * V t , j is an imaginary number, P max is the maximum active power output of the new energy power system equivalent model, K P1 is the first control parameter of the new energy active current, K P2 is the second control parameter of the new energy active current, K Q1The control parameter of the new energy reactive current.

[0141] Optionally, the machine side margin M P,R and the grid side margin M Z,R are calculated based on the new energy repeatedly crossing the boundary expression

[0142] The machine side margin M P and the grid side margin M z are defined as

[0143]

[0144]

[0145] According to the new energy repeatedly crossing the boundary expression, when P max = P R = I P * V t , the expression of Z th is obtained as

[0146]

[0147]

[0148] According to the new energy repeatedly crossing the boundary expression, the expression of Z th , the defined machine side margin M P and the grid side margin M z , the calculation formula of the machine side margin M P,R and the grid side margin M Z,R under the repeatedly crossing the boundary is obtained as

[0149]

[0150]

[0151]

[0152] According to the calculation formula, the machine side margin M P,R and the grid side margin M Z,R under the repeatedly crossing the boundary are determined.

[0153] In the formula, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I QsetE is the voltage of the point of common coupling, P is the active power output of the new energy power system in the current operating state of the equivalent model, Z is the line impedance amplitude of the new energy power system in the current operating state of the equivalent model, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current of the new energy before entering the low-voltage ride-through, I Pset is the active current set for the new energy.

[0154] Optionally, the method further comprises:

[0155] According to the unit and new energy parameters, a new energy conventional boundary expression is established; wherein the new energy conventional boundary expression is:

[0156] E 2 -2P max (1-cosθ)Z th =0;

[0157] Based on the new energy conventional boundary expression, the machine-side margin M P,N and the grid-side margin M Z,N under the conventional boundary are calculated; wherein the calculation formula of the machine-side margin M P,N and the grid-side margin M Z,N under the conventional boundary is:

[0158]

[0159]

[0160] In the formula, E is the voltage of the point of common coupling, P max is the maximum active power output of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, Z is the line impedance amplitude of the new energy power system in the current operating state of the equivalent model, P is the active power output of the new energy power system in the current operating state of the equivalent model;

[0161] The machine-side margin M P,R and the grid-side margin M Z,R under the repeated ride-through boundary are compared with the machine-side margin M P,N and the grid-side margin M Z,N under the conventional boundary;

[0162] According to the comparison result, the calculation accuracy of the machine-side margin M P,R and the grid-side margin M Z,R under the repeated ride-through boundary is evaluated.

[0163] Optionally, the new energy conventional boundary expression is established according to the parameters of the generating units and the new energy, and the establishment includes:

[0164] The parameters of the generating units and the load parameters in the system are acquired, including the voltage E of the point of common coupling, the voltage amplitude V of the grid-connected point of the new energy device t , and the phase angle a of the grid-connected point of the new energy device;

[0165] The conventional boundary expression is established according to the acquired parameters, and the calculation formula is as follows:

[0166]

[0167]

[0168] The angle a is eliminated, and the conventional boundary expression is simplified as:

[0169]

[0170] When the new energy is constant power output, Q = 0, the conventional boundary expression is further simplified as:

[0171]

[0172] The two solutions of V t are

[0173]

[0174] When , V t has a repeated solution, and the repeated solution of V t is:

[0175]

[0176] That is, the critical voltage value is

[0177]

[0178] The critical voltage value is substituted into the repeated solution of V t , and the maximum active power P max at the critical voltage value is obtained. th The expression of the line impedance amplitude Z th is:

[0179]

[0180] The solution of Z th is:

[0181]

[0182] Based on V t The heavy solution is obtained:

[0183]

[0184] Since P max is greater than 0, Z th is greater than 0, and the negative solution of the formula is meaningless, that is:

[0185]

[0186] When , the Z th corresponding to the nose point of the P-V curve is obtained, and the expression of the line impedance amplitude and the maximum active power is:

[0187]

[0188] The expression of the new energy operating under the conventional boundary is:

[0189] E 2 -2P max (1-cosθ)Z th =0;

[0190] In the formula, P max is the maximum active power of the equivalent model of the new energy power system, Z th,max is the maximum line impedance amplitude of the equivalent model of the new energy power system under the conventional boundary, V L is the low voltage ride through judgment threshold of the new energy, P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system, Q is the reactive power of the new energy under the current operating state of the equivalent model of the new energy power system, V t is the voltage amplitude of the grid connection point of the new energy equipment, θ is the phase angle of the line impedance of the equivalent model of the new energy power system, E is the voltage of the point of common coupling, Z th is the line impedance amplitude of the equivalent model of the new energy power system under the conventional boundary, and Z is the line impedance amplitude of the equivalent model of the new energy power system under the current operating state.

[0191] Optionally, the new energy conventional boundary expression is used to calculate the machine side margin M P,N and the grid side margin M Z,N , including:

[0192] The machine side margin M P and the grid side margin M z are defined as:

[0193]

[0194]

[0195] According to the new energy conventional boundary expression, the defined machine side margin M P With the network side margin M z , the calculation formula of the machine side margin M P,N With the network side margin M Z,N Under the conventional boundary:

[0196]

[0197]

[0198] In the formula, E is the voltage of the public connection point, P max The maximum active power of the equivalent model of the new energy power system, θ is the phase angle of the line impedance of the equivalent model of the new energy power system, Z th The line impedance amplitude of the equivalent model of the new energy power system under the conventional boundary, Z is the line impedance amplitude of the equivalent model of the new energy power system under the current operating state, and P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system.

[0199] In the embodiment of the application, Figure 2 It is a comparison chart of the maximum power of the new energy and the line impedance under the conventional boundary and the repeated crossing boundary, Figure 3 It is a margin comparison chart of the new energy conventional boundary and the repeated crossing boundary when θ=90°. Combined with Figure 2 And Figure 3 It is shown that the calculation accuracy of the machine side margin M P,R With the network side margin M Z,R Under the repeated crossing boundary is obviously better than the calculation accuracy of the machine side margin M P,N With the network side margin M Z,N Under the conventional boundary.

[0200] As shown above, the application first establishes a new energy repeated crossing boundary expression according to the parameters of the unit and the new energy, and then calculates the machine side margin and the network side margin under the repeated crossing boundary based on the new energy repeated crossing boundary expression. The application derives the repeated crossing boundary of the new energy crossing control, obtains the machine side margin and the network side margin under different boundaries, and respectively derives the expressions of the maximum power and the line impedance for the repeated crossing boundary, and calculates different margins, so that it can be applied to the calculation of the new type of transient instability phenomenon dominated by the new energy crossing control.

[0201] Exemplary apparatus

[0202] The application also provides a boundary condition and multi-dimensional margin calculation device for new energy repeated crossing instability, comprising:

[0203] The expression establishing module is configured to establish a new energy repeated crossing boundary expression according to the unit and the new energy parameters, wherein the new energy repeated crossing boundary expression is:

[0204]

[0205] The multi-dimensional margin calculation module is configured to calculate the machine side margin M P,R and the grid side margin M Z,R under the repeated crossing boundary based on the new energy repeated crossing boundary expression. P,R The calculation formula of the machine side margin M Z,R and the grid side margin M th under the repeated crossing boundary is:

[0206]

[0207]

[0208]

[0209] In the formula, Z th is the line impedance amplitude under the conventional boundary of the new energy power system equivalent model, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I Qset is the reactive current set by the new energy, E is the point of common coupling voltage, P is the active power of the new energy power system equivalent model under the current operating state, Z is the line impedance amplitude of the new energy power system equivalent model under the current operating state, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current before the new energy enters the low voltage ride through, I Pset is the active current set by the new energy.

[0210] The boundary condition of the new energy repeated crossing instability and the multi-dimensional margin calculation device of the embodiment of the application correspond to the boundary condition of the new energy repeated crossing instability and the multi-dimensional margin calculation method of another embodiment of the application, and details are not repeated here.

[0211] Exemplary electronic device

[0212] Figure 4 is the structure of the electronic device provided by an exemplary embodiment of the application. As shown in Figure 4 , the electronic device 40 includes one or more processors 41 and a memory 42.

[0213] The processor 41 can be a central processing unit (CPU) or other form of processing unit that has data processing and / or instruction execution capabilities and can control other components in the electronic device to perform desired functions.

[0214] The memory 42 can include one or more computer program products that can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory, for example, can include random access memory (RAM), cache memory, and / or the like. The non-volatile memory, for example, can include read only memory (ROM), hard disk, flash memory, and / or the like. One or more computer program instructions can be stored on the computer-readable storage media, which the processor 41 can execute to implement the method of information mining on the history change record of the software program of various embodiments of the present application and / or other desired functions described above. In one example, the electronic device can further include an input device 43 and an output device 44, which are interconnected through a bus system and / or other form of connection mechanism (not shown).

[0215] In addition, the input device 43 can further include, for example, a keyboard, a mouse, and / or the like.

[0216] The output device 44 can output various information to the outside. The output device 44 can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto, and / or the like.

[0217] Of course, in order to simplify, Figure 4 Only some of the components in the electronic device related to the present application are shown in FIG. 1, and components such as buses, input / output interfaces, and / or the like are omitted. In addition, the electronic device can further include any other appropriate components according to specific application cases.

[0218] Exemplary computer program product and computer readable storage medium

[0219] In addition to the above-described method and device, embodiments of the present application can be a computer program product including computer program instructions that, when executed by a processor, cause the processor to perform steps of the methods according to various embodiments of the present application described in the above "Exemplary Methods" section of the specification.

[0220] The computer program product can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server.

[0221] Furthermore, embodiments of the present application can also be a computer readable storage medium, having stored thereon computer program instructions which, when executed by a processor, cause the processor to carry out the steps described in the above "Exemplary Method" section of the present specification for the method of information mining on historical change records according to various embodiments of the present application.

[0222] The computer readable storage medium can be a combination of one or more computer readable media. The computer readable media can be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium can include, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium include an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0223] The above description sets forth numerous specific details to provide a thorough understanding of the application. However, those of skill in the art will appreciate that the application can be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail since they would be understood as if described herein. The present application can be practiced with the specific details set forth or with other components, materials, acts, or operations not specifically described herein, without departing from the spirit or scope of the application. Likewise, the term "comprising" is used herein to mean including, consisting of, or consisting essentially of, and the like.

[0224] The various embodiments described in this specification are presented by way of example, and not limitation. Each embodiment is presented in a separate section, and each section focuses on the differences between that embodiment and the other embodiments. Each section can be read in isolation from the other sections, and the disclosure is not limited to any particular embodiment. For system embodiments, the description is relatively brief because the system embodiments are essentially the same as the method embodiments. The relevant portions of the method embodiments are incorporated into the description of the system embodiments.

[0225] The block diagrams of the devices, systems, apparatuses, systems referred to in this disclosure are only meant to be illustrative examples and are not intended to require or imply that the connections, arrangements, configurations shown in the block diagrams are required. These devices, systems, apparatuses, systems can be connected, arranged, configured in any manner as will be appreciated by those skilled in the art. Words such as "including," "containing," "comprising," and the like are to be construed in an inclusive fashion, meaning that "consisting of" is to be read into each of such terms, and that "consisting of" and "consisting essentially of" are each permissible claim limitations. The terms "or," "and," and "and / or" as used herein are to be interpreted as an inclusive or meaning any one or any combination of the listed possible options so that, for example, "A or B" means "A or B or both." The terms "and," "and / or" as used herein are to be interpreted as an inclusive or meaning any one or any combination of the listed possible options so that, for example, "A and B" means "A and B or A or B." The term "such as" is to be read as meaning "such as but not limited to."

[0226] The methods and systems of the present application can be implemented in a number of ways. For example, the methods and systems of the present application can be implemented via software, hardware, firmware, or any combination of software, hardware, and firmware. The above described order of steps for the methods is merely illustrative and the steps of the methods of the present application are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present application can also be implemented as a program recorded on a recording medium, which includes machine readable instructions for implementing the methods according to the present application. Thus, the present application also covers recording media storing programs for executing the methods according to the present application.

[0227] It is also to be noted that in the systems, apparatuses, and methods of the present application, various components or steps can be decomposed and / or recombined. These decompositions and / or recombinations are to be considered as equivalent to the present application. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0228] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit embodiments of the present application to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those of ordinary skill in the art will appreciate a variety of modifications, alternatives, permutations, additions, and sub-combinations, which fall within the scope of the application.

Claims

1. A boundary condition and multi-dimensional margin calculation method for new energy repeated crossing instability, characterized in that, Comprise: According to the parameters of the unit and new energy, the expression of the new energy repeated crossing boundary is established; wherein, the expression of the new energy repeated crossing boundary is: Based on the new energy repeatedly crossing the boundary expression, the machine side margin M under the repeatedly crossing boundary is calculated P,R With the grid side margin M Z,R ; Wherein the machine side margin M under the repeatedly crossing boundary P,R With the grid side margin M Z,R The calculation formula is: In the formula, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I Qset is the reactive current set for the new energy, E is the point of common coupling voltage, P is the active power of the new energy power system equivalent model under the current operating state, Z is the line impedance amplitude of the new energy power system equivalent model under the current operating state, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current of the new energy before entering the low voltage ride through, I Pset is the active current set for the new energy.

2. The method of claim 1, wherein, According to the parameters of the unit and new energy, the expression of the new energy repeated crossing boundary is established, comprising: Obtain system parameters and load parameters of each unit, including common connection point voltage E, first control parameter K of active current of new energy P1 and second control parameter K P2 , control parameter K of reactive current of new energy Q1 , grid-connected point voltage amplitude V of new energy equipment t , grid-connected point voltage phase angle α of new energy equipment According to the obtained parameters, the conventional boundary expression of the unit and new energy parameters is established, and the calculation formula is as follows: Eliminate the angle alpha, and the conventional boundary expression is simplified as: The expression of the current characteristics of the new energy during low voltage ride through is determined as: I P = SK P1 V t + K P2 I P0 + SI Pset ; I Q = SK Q1 (V L - V t + SI Qset ; The expression of the power flow characteristics of the new energy is determined as: During low voltage ride through, the expression of the current characteristics of the new energy is substituted into the expression of the power flow characteristics of the new energy, and the following is obtained: The analytical expression Z of the voltage phase angle with POC point is solved th is: The expression of the current characteristics of the new energy and the expression of the power flow characteristics of the new energy are substituted into the simplified conventional boundary expression, and the following is obtained: When V t = V L , then the new energy runs under the new energy repeated crossing boundary expression of repeated crossing boundary: In the formula, P is the active power output of the new energy power system equivalent model under the current operating state, Q is the reactive power output of the new energy power system equivalent model under the current operating state, V t is the voltage amplitude of the grid-connected point of the new energy equipment, θ is the phase angle of the line impedance of the new energy power system equivalent model, E is the point of common coupling voltage, α is the phase angle of the grid-connected point voltage of the new energy equipment, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low-voltage ride-through judgment threshold, V L is the new energy low-voltage ride-through judgment threshold, I P is the active current under the current operating state of the new energy, I Q is the reactive current under the current operating state of the new energy, S is the rated capacity of the new energy, I P0 is the active current before the new energy enters the low-voltage ride-through, V L is the new energy low-voltage ride-through judgment threshold, I Pset is the set active current of the new energy, I Qset is the set reactive current of the new energy, P R is the active power output of the new energy, P R = I P * V t , P L is the active power consumption of the load, Q R is the reactive power output of the new energy, Q R = I Q * V t , j is an imaginary number, P max is the maximum active power output of the new energy power system equivalent model, K P1 is the first control parameter of the new energy active current, K P2 is the second control parameter of the new energy active current, K Q1 is the control parameter of the new energy reactive current.

3. The method of claim 1, wherein, The new energy-based repeated crossing boundary expression is used to calculate the machine side margin M under the repeated crossing boundary P,R and the grid side margin M Z,R , comprising: Defining machine side margin M P and grid side margin M z is: According to the new energy repeated crossing boundary expression, when P max = P R = I P * V t , the expression of Z th is obtained as follows: A = [(SK P1 V L + K P2 I P0 + SI Pset ) 2 + (SI Qset ) 2 ] V L 2 B = [(SK P1 V L + K P2 I P0 + SI Pset ) cos θ + SI Qset sin θ] V L 3 According to the new energy repeated crossing boundary expression, Z th The expression of M P The defined machine side margin M z , get the machine side margin M P,R And the calculation formula of the grid side margin M Z,R of repeated crossing boundary: According to the calculation formula, the machine side margin M under repeated crossing of the boundary is determined P,R and the grid side margin M Z,R ; In the formula, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I Qset is the reactive current set for the new energy, E is the point of common coupling voltage, P is the active power of the new energy power system equivalent model under the current operating state, Z is the line impedance amplitude of the new energy power system equivalent model under the current operating state, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current of the new energy before entering the low voltage ride through, I Pset is the active current set for the new energy.

4. The method of claim 1, wherein, Also comprise: According to the parameters of the unit and new energy, the expression of the new energy conventional boundary is established; wherein, the expression of the new energy conventional boundary is: E 2 -2P max (1-cosθ)Z th =0; Based on the conventional boundary expression of new energy, the machine side margin M under the conventional boundary is calculated P,N and the grid side margin M Z,N ; wherein the machine side margin M under the conventional boundary P,N and the grid side margin M Z,N The calculation formula is: wherein E is the common connection point voltage, P max is the maximum active power of the equivalent model of the new energy power system, θ is the phase angle of the line impedance of the equivalent model of the new energy power system, Z th is the line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, Z is the line impedance amplitude under the current operating state of the equivalent model of the new energy power system, and P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system. The margin M under the boundary on the generator side is compared with the margin M under the boundary on the grid side P,R The margin M under the boundary on the generator side is compared with the margin M under the boundary on the grid side Z,R The margin M under the boundary on the generator side is compared with the margin M under the boundary on the grid side P,N The margin M under the boundary on the generator side is compared with the margin M under the boundary on the grid side Z,N The margin M under the boundary on the generator side is compared with the Based on the results of the comparison, the calculation accuracy of the under-machine side margin M P,R and the network side margin M Z,R is evaluated.

5. The method of claim 4, wherein, According to the parameters of the unit and new energy, the expression of the new energy conventional boundary is established, comprising: Obtain the parameters of each unit and load in the system, including the voltage E at the point of common coupling, the voltage amplitude V at the point of interconnection of the new energy equipment, and the phase angle α of the voltage at the point of interconnection of the new energy equipment t and the phase angle α of the voltage at the point of interconnection of the new energy equipment According to the obtained parameters, the conventional boundary expression of the unit and new energy parameters is established, and the calculation formula is as follows: Eliminate the angle alpha, and the conventional boundary expression is simplified as: When the new energy is constant power output, Q=0, then the conventional boundary expression is further simplified as: Then V t The two solutions of When V t The heavy solution, V t The heavy solution is: That is, the critical voltage value is Substitute the critical voltage value into V t In the heavy solution of the expression, the maximum active power P max and the line impedance amplitude Z th The expression is: Solving for Z th is: Based on V t The heavy solution gives: Since P max greater than 0, Z th greater than 0, the negative solution of the equation is discarded, i.e.: When the Z th , the expression of line impedance amplitude and maximum active power is: Then the expression of the new energy operating under the conventional boundary is: E 2 -2P max (1-cosθ)Z th =0; In the formula, P max is the maximum active power of the equivalent model of the new energy power system, Z th,max is the maximum line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, V L is the new energy low voltage ride through judgment threshold, P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system, Q is the reactive power of the new energy under the current operating state of the equivalent model of the new energy power system, V t is the grid-connected point voltage amplitude of the new energy device, θ is the line impedance phase angle of the equivalent model of the new energy power system, E is the point of common coupling voltage, Z th is the line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, Z is the line impedance amplitude under the current operating state of the equivalent model of the new energy power system.

6. The method of claim 4, wherein, The conventional boundary-based new energy expression is used to calculate the machine side margin M under the conventional boundary P,N and the grid side margin M Z,N , comprising: Defining machine side margin M P and grid side margin M z is: According to the new energy conventional boundary expression, the defined machine side margin M P With the grid side margin M z , the calculation formula of the machine side margin M P,N With the grid side margin M Z,N under the conventional boundary is obtained: wherein E is the common connection point voltage, P max is the maximum active power of the equivalent model of the new energy power system, θ is the phase angle of the line impedance of the equivalent model of the new energy power system, Z th is the line impedance amplitude under the conventional boundary of the equivalent model of the new energy power system, Z is the line impedance amplitude under the current operating state of the equivalent model of the new energy power system, and P is the active power of the new energy under the current operating state of the equivalent model of the new energy power system.

7. A new energy repeated crossing instability boundary condition and multi-dimensional margin calculation device, characterized in that, Comprise: The expression establishment module is used for establishing the expression of the new energy repeated crossing boundary according to the parameters of the unit and new energy; wherein, the expression of the new energy repeated crossing boundary is: A multi-dimensional margin calculation module is configured to calculate a machine-side margin M under repeated crossing of a boundary based on a new energy repeated crossing boundary expression P,R and a grid-side margin M Z,R ; wherein the machine-side margin M under repeated crossing of a boundary P,R and the grid-side margin M Z,R are calculated according to the following formula: In the formula, Z th is the line impedance amplitude of the new energy power system equivalent model under the conventional boundary, V L is the new energy low voltage ride through judgment threshold, P max is the maximum active power of the new energy power system equivalent model, θ is the line impedance phase angle of the new energy power system equivalent model, S is the rated capacity of the new energy, I Qset is the reactive current set for the new energy, E is the point of common coupling voltage, P is the active power of the new energy power system equivalent model under the current operating state, Z is the line impedance amplitude of the new energy power system equivalent model under the current operating state, K P1 is the first control parameter of the active current of the new energy, K P2 is the second control parameter of the active current of the new energy, I P0 is the active current of the new energy before entering the low voltage ride through, I Pset is the active current set for the new energy.

8. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, and the computer program is used for executing the method in any one of claims 1-6.

9. An electronic device, comprising: The electronic device comprises: A processor; A memory for storing executable instructions of the processor; The processor is used for reading the executable instructions from the memory and executing the instructions to realize the method in any one of claims 1-6.

Images