A method and system for calculating the synchronization grid-connection success rate of a phase modifier

Abstract

The application belongs to the field of grid connection technology, and particularly relates to a method and system for calculating the synchronization grid connection success rate of a phase modifier, the method comprising: collecting the frequency difference setting value, phase angle difference setting value and slip rate of the synchronization grid connection of the phase modifier, calculating the start point, end point and length of each grid connection time period under different initial phase angle differences, the number of grid connection time periods, and then calculating the total grid connection length; and comparing the length of each grid connection time period with the grid connection action delay time of the phase modifier to obtain the grid connection success rate. The application obtains the condition setting for successful grid connection by calculating the relationship between the synchronization grid connection length and the grid connection action delay time of the phase modifier, improves the accuracy of the grid connection success rate calculation, effectively reduces the grid connection times of the phase modifier, and improves the grid connection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of grid connection technology, specifically relating to a method and system for calculating the success rate of synchronous grid connection of synchronous condensers. Background Technology

[0002] As the proportion of new energy sources in the power system increases, the reactive power support capacity of new power systems is declining, posing a serious threat to the safe and stable operation of the power grid. Synchronous condensers, mechanical rotating devices, are characterized by high reliability, large capacity, bidirectional reactive power generation and absorption, and strong instantaneous support capability. Under grid disturbances, they can provide large-capacity dynamic reactive power in a timely manner through strong excitation. Therefore, to ensure the safety, reliability, and economy of the power grid, synchronous condensers have been widely used in the power grid.

[0003] When a synchronous condenser is quickly connected to the grid, the generator rotor is typically accelerated from a turning gear state to a certain speed by a static frequency converter (SFC), after which the SFC disengages. Due to the loss of driving force, the synchronous condenser rotor begins to decelerate inertially with a slip rate that varies according to a certain pattern. During this inertial deceleration, after the excitation establishes its terminal voltage, the synchronizing device begins to search for a synchronization point that meets the grid connection conditions. Once the synchronization point is found, the synchronizing device sends a closing command to the synchronizing relay to initiate grid connection. Because there is a certain time delay between the synchronizing relay receiving the closing command and the closing circuit operating, i.e., a lower limit value T exists for the operating delay time... dq The duration of synchronous points that meet the grid connection conditions should exceed T. dq For grid connection to be successful, the calculation of the duration of the synchronization point is crucial. Existing methods for calculating grid connection success rate calculate the success rate based on the frequency difference setting and phase angle difference setting between the synchronous condenser and the power grid, but lack calculation of the grid connection time period. Furthermore, they do not consider the impact of synchronous relays, system sampling delay, and measurement errors on the system's response time in actual situations, resulting in inaccurate calculations of the grid connection success rate. Summary of the Invention

[0004] To overcome the above-mentioned defects, the purpose of this invention is to provide a method and system for calculating the success rate of synchronous grid connection of synchronous condensers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for calculating the success rate of synchronous grid connection of synchronous condensers includes:

[0007] The frequency difference setpoint Δf for synchronous grid connection of the acquisition phase condenser Set Phase angle difference setting value ΔA Set and slip Calculate the start, end, and duration of each grid connection time period under each initial phase angle difference ΔA0, as well as the number of grid connection time periods, and then calculate the total grid connection time. Then, calculate the total grid connection time by comparing the duration of each grid connection time period with the synchronous condenser's action delay time T. dq By comparing the results, the grid connection success rate can be obtained.

[0008] Preferably, the start and end points of the grid connection time period and the calculation method for the grid connection time period are as follows:

[0009] To simplify calculations and facilitate expression, the following symbols are defined:

[0010]

[0011]

[0012]

[0013] In the formula, This represents the definition of mathematical symbols, where T1(n) and T2(n) respectively represent the mathematical symbols used in mathematical notation. The start and end points of grid connection within the time period, T3(n) and T4(n) respectively represent the start and end points of grid connection within the time period. The grid connection time start and end points within the time period, λ1(n) and λ2(n) are mathematical expressions defined for simplified representation. Indicates rounding down to the nearest integer. Let λ1(n) and λ2(n) represent the largest integers that can be obtained when λ1(n) and λ2(n) are greater than 0, respectively, where n is an integer; ∪ represents the union of sets. Indicates n=1 to The merge operation of each set, Indicates n=2 to The merge operation of each set;

[0014] (1) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0015]

[0016] (2) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0017]

[0018] (3) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0019]

[0020] (4) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0021]

[0022] (5) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0023]

[0024] (6) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0025]

[0026] (7) When At that time, the synchronous condenser did not have a time period available for grid connection, and grid connection failed.

[0027] Preferably, the method for calculating the total grid connection time is as follows:

[0028] (1) When and The total grid connection time is calculated as follows:

[0029] (2) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0030] (3) When and The total grid connection time is calculated as follows:

[0031] (4) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0032] (5) When At that time, the total time for the synchronous condenser to be connected to the grid is 0.

[0033] Preferably, the grid connection success rate is calculated as follows:

[0034] By comparing the duration of each grid connection period with the synchronous condenser action delay time T dq Comparisons were made, and the duration of each grid-connected time period under different initial phase angle differences ΔA0 was calculated to be no less than T. dq The proportion of this is the grid connection success rate.

[0035] A system for calculating the success rate of synchronous grid connection of synchronous condensers includes:

[0036] The acquisition module obtains the frequency difference setpoint Δf for synchronous grid connection of the synchronous condenser. Set Phase angle difference setting value ΔA Set slip and the initial phase angle difference ΔA0;

[0037] The calculation module calculates the start, end, and duration of each grid-connected time period under different initial phase angle differences, as well as the number of grid-connected time periods, based on the information collected by the acquisition module, and then calculates the total grid-connected time.

[0038] The discrimination module determines the time by comparing the duration of each grid connection period with the synchronous condenser's action delay time T. dq By comparing the results, the grid connection success rate can be obtained.

[0039] Preferably, the start and end points of the grid connection time period and the calculation method for the grid connection time period are as follows:

[0040] To simplify calculations and facilitate expression, the following symbols are defined:

[0041] In the formula, This represents the definition of mathematical symbols, where T1(n) and T2(n) respectively represent the mathematical symbols used in mathematical notation. The start and end points of grid connection within the time period, T3(n) and T4(n) respectively represent the start and end points of grid connection within the time period. The grid connection time start and end points within the time period, λ1(n) and λ2(n) are mathematical expressions defined for simplified representation. Indicates rounding down to the nearest integer. Let λ1(n) and λ2(n) represent the largest integers that can be obtained when λ1(n) and λ2(n) are greater than 0, respectively, where n is an integer; ∪ represents the union of sets. Indicates n=1 to The merge operation of each set, Indicates n=2 to The merge operation of each set;

[0042] (1) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0043]

[0044] (2) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0045]

[0046] (3) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0047]

[0048] (4) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0049]

[0050] (5) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0051]

[0052] (6) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0053]

[0054] (7) When At that time, the synchronous condenser did not have a time period available for grid connection, and grid connection failed.

[0055] Preferably, the method for calculating the total grid-connectable time is as follows:

[0056] (1) When and The total grid connection time is calculated as follows:

[0057] (2) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0058] (3) When and The total grid connection time is calculated as follows:

[0059] (4) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0060] (5) When At that time, the total time for the synchronous condenser to be connected to the grid is 0.

[0061] Preferably, the discrimination module determines the relationship between the duration of each grid connection time period and the synchronous condenser action delay time T. dq The comparison yields the grid connection success rate, including:

[0062] By comparing the duration of each grid connection period with the synchronous condenser action delay time T dq Comparisons were made, and the duration of each grid-connected time period under different initial phase angle differences ΔA0 was calculated to be no less than T. dq The proportion of this is the grid connection success rate.

[0063] The positive and beneficial effects of this invention are:

[0064] This invention calculates the start and end points of the synchronous grid connection time by using slip rate, frequency difference set value, phase angle difference set value, and initial phase angle difference value. This yields the duration of each grid connection period and the total duration of the grid connection period. By analyzing the relationship between the grid connection duration and the system action delay time, the conditions for successful grid connection are set. This provides convenience for setting the grid connection conditions of synchronous devices, clearly identifies the time periods during which successful grid connection can be achieved, and performs grid connection operations, thereby improving the accuracy of grid connection success rate, effectively reducing the number of times synchronous condensers need to be connected to the grid, and improving grid connection efficiency. Attached Figure Description

[0065] Figure 1 The figure shows the simulation results of the success rate of synchronous condenser grid connection in existing technical literature.

[0066] Figure 2 This is a diagram showing the total grid-connection time under different initial phase angle differences according to the present invention;

[0067] Figure 3 This is a diagram showing the start, end, and duration of grid connection when the initial phase angle difference is 30°. Detailed Implementation

[0068] The present invention will be further described below with reference to some specific embodiments.

[0069] Example 1: Analysis of the trends of frequency difference and phase difference over time

[0070] After the SFC exits, the synchronous condenser begins to coast. Starting from the moment the actual network frequency difference enters the frequency difference set by the synchronizing device, the relationship between the network frequency difference and time can be expressed as:

[0071]

[0072] In the formula: Δf is the frequency difference between the machine and the network, f Se To adjust the camera frequency, f Net Let Δf be the power grid frequency. Set This is the allowable frequency difference setting value for grid connection of synchronous devices. Let t represent the slip ratio and t be time.

[0073] At t = 0, the frequency difference is Δf Set As time t increases, the frequency difference Δf on the machine-network side gradually decreases and changes from positive to negative until Δf = -Δf. Set Then it exits the frequency deviation setpoint range. Since the slip rate changes little within the frequency deviation range, therefore... If it can be approximated as a constant, then the grid-connected time period exists. Within the range.

[0074] At t=0, let the initial phase angle difference between the synchronous condenser and the grid voltage be ΔA0. Then, during the process of the synchronizing device capturing grid synchronization within the frequency difference setpoint interval, the relationship between the phase angle difference and time is as follows:

[0075] ΔA=A Se -A Net =ΔA0+360∫Δfdt (2)

[0076] In the formula: ΔA is the phase angle difference between the grid and the generator voltage; A Se To adjust the camera voltage phase angle; A Net This represents the phase angle of the grid voltage.

[0077] Substituting equation (1) into equation (2), we can obtain the relationship between the phase angle difference and time:

[0078]

[0079] From equation (3), it can be seen that at t=0, the synchronous condenser begins to enter the frequency difference setpoint range, at which time Δf=Δf Set , ΔA=ΔA0; in hour, ΔA reaches its maximum value exist When Δf decreases to -Δf Set ΔA then returns to ΔA0, and the frequency difference no longer satisfies the condition.

[0080] Due to the change in phase angle... It is symmetrical from left to right, if As a constant, the network frequency difference changes uniformly from Δf Set Decrease to -Δf Set Then the grid connection time period can be... It is symmetrical about the left and right sides of the axis of symmetry.

[0081] Example 2: Calculation of Grid Connection Time Point

[0082] When the frequency difference Δf and phase angle difference ΔA on the grid side simultaneously meet the set value conditions, the synchronizing device sends a closing command to the synchronizing relay. After receiving the command, the synchronizing relay starts the closing action. After the synchronizing relay successfully closes, the synchronous condenser achieves grid connection.

[0083] The initial moment is defined as the moment when the upper limit of the frequency difference setting value is met, that is, at this time t=0 and the frequency difference condition has been met. The synchronizing device starts to judge the phase angle difference condition on the machine-grid side. If condition (4) is met, the system starts to connect to the grid.

[0084] -ΔA Set ≤mod 360 (ΔA)≤ΔA Set (4)

[0085] Since the phase angle changes periodically over 360°, mod in the formula 360 (·) indicates taking the remainder when divided by 360.

[0086] From equation (4), we can obtain

[0087]

[0088] Where n = 0, 1, 2, ... are integers.

[0089] Solve for the left half of equation (5).

[0090]

[0091] The time required to meet the conditions is

[0092] t∈[T1(n),T4(n)] (7)

[0093] In the formula, T1(n) and T4(n) represent the values ​​in the following contexts: The grid connection start and end points within the time period are defined by λ1(n), which is a simplified mathematical symbol. To guarantee the existence of a solution in equation (7), λ1(n) ≥ 0, i.e.

[0094]

[0095] From equation (8), we can obtain the condition that the integer n must satisfy:

[0096]

[0097] In the formula, This indicates rounding down. This represents the largest integer that can be obtained when λ1(n)≥0.

[0098] Similarly, solving the right half of equation (5) yields...

[0099]

[0100] The time required to meet the conditions is

[0101] t∈{[0,T2(n)]∪[T3(n),∞]} (11)

[0102] In the formula, T2(n) and T3(n) respectively represent the... The grid connection time endpoint and start point exist within the time period, and λ2(n) is a mathematical symbol defined for simplification. To guarantee the existence of a solution in equation (11), λ2(n) ≥ 0, and the integer n must satisfy the following condition:

[0103]

[0104] In the formula, This represents the largest integer that can be obtained when λ2(n)≥0.

[0105] From equations (7) and (11), the existing grid connection time period can be obtained as follows:

[0106] t∈{[T1(n),T2(n)]∪[T3(n),T4(n)]} (13)

[0107] From equations (9) and (12), we can see that Therefore, the range of values ​​for the integer n is:

[0108]

[0109] From equation (13), we can see that Since the time period that satisfies the frequency difference condition is Therefore, the following calculations address different scenarios regarding the grid connection start time, end time, and grid connection period. Specifically, the grid connection start time is determined by the relationship between T1(n), T2(n) and 0, and the grid connection time is determined by the relationship between T3(n), T4(n) and 0. The relationship is used to determine the end point of grid connection time, where ∪ represents the union of sets. Indicates n=1 to The merge operation of each set, Indicates n=2 to The cumulative merge operation for each set is detailed below:

[0110] (1) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0111]

[0112] (2) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0113]

[0114] (3) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0115]

[0116] (4) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0117]

[0118] (5) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0119]

[0120] (6) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0121]

[0122] (7) When At that time, there was no available time slot for grid connection, so grid connection could not be successfully completed.

[0123] It should be noted that:

[0124] When calculating the starting point of time, if there is a grid connection period, T2(1) > 0 for any case, indicating that the total starting point of time will not exceed T2(1). Therefore, it is not necessary to determine whether the time point after T2(1) is the total starting point of the grid connection period. Similarly, in any case, This indicates that the total grid connection time always ends after T3(1);

[0125] All other things being equal, with compared to, In some cases, there will be more available grid connection time slots, but the increase can only be one, which is... when At that time, the maximum value of the phase angle difference change is still within the range of the phase angle difference set value, therefore, including the midpoint of time... time period The internal conditions for grid connection are met. When... At that time, the maximum phase angle difference does not meet the grid connection conditions, therefore this time period is missing;

[0126] In either case, the grid connection time can be... Centered on the grid, symmetrical on both sides, meaning that the grid connection start time and grid connection end time are two mutually symmetrical time periods, and the grid connection duration is equal, i.e., [0,t2(0)] and The durations are equal.

[0127] Example 3: Total Grid Connection Time

[0128] The total grid connection time under various conditions can be obtained by summing up the time for each segment.

[0129] (1) When and The total grid connection time is calculated as follows:

[0130] (2) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0131] for And ΔA0>ΔA Set Although ΔA0+ΔA Set The size relationship with 360 affects the start and end points of the network connection time and the distribution of the network connection time period, but it is unrelated to the total network connection time.

[0132] (3) When and The total grid connection time is calculated as follows:

[0133] (4) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0134] for And ΔA0>ΔA Set Although ΔA0+ΔA Set The size relationship with 360 affects the start and end points of the grid connection time and the distribution of the grid connection time period, but it is unrelated to the total grid connection time.

[0135] (5) When At that time, the total time for the synchronous condenser to be connected to the grid is 0.

[0136] Example 4 Simulation Verification

[0137] The grid connection success rate proposed in the literature "Calculation Method for Coasting Grid Connection Success Rate of Large Synchronous Condensers" (Yang Heming, Zheng Yuping, Wang Xiaohong, Jian Youzong, and Hu Jing, Automation of Electric Power Systems, vol.42, no.24, pp.74-78, 2018) is:

[0138]

[0139] From equation (21), it can be seen that in Under certain conditions, the synchronization success rate is directly proportional to the first power of the phase angle difference setting value. The larger the phase angle difference setting value, the higher the synchronization success rate. The synchronization success rate is also directly proportional to the square of the frequency difference setting value. The larger the frequency difference setting value, the faster the synchronization success rate increases.

[0140] Since the initial value of the phase angle difference is randomly selected between 0 and 360°, therefore when ΔA Set =40°, Δf Set When = 0.45Hz, for ΔA0∈[0,360], then the grid connection success rate obtained by equation (21) is as follows: Figure 1 As shown, its grid connection success rate is 100%, meaning that it can successfully connect to the grid for any ΔA0.

[0141] Because of system delays in synchronizing devices, such as the delay between receiving and executing a closing command by a synchronizing relay, if the system delay exceeds the system's grid-connection time, grid connection will not succeed. Therefore, the total grid-connection time for different initial phase angle differences can be obtained using equations (15)-(20) of this invention, such as... Figure 2 As shown, the total time does not change monotonically with the increase of the initial phase angle difference. In particular, when ΔA0 = 30°, the total grid connection time is 0.124s, which is the shortest grid connection time. The grid connection period is as follows. Figure 3 As shown, at t=0, the network frequency difference has reached the upper limit Δf of the frequency difference setting value. Set This means that the frequency difference between the machine and the grid meets the grid connection frequency difference setting conditions, and the phase angle difference between the machine and the grid is ΔA=ΔA0=30°<ΔA Set =40°, therefore, at this time, both the frequency difference and phase angle difference meet the grid connection conditions and grid connection can be achieved. As time goes by, at t = T2(0) = 0.062s, the phase angle difference between the machine and the grid reaches the upper limit of the grid connection phase angle difference setting value, that is, at this time ΔA = ΔA Set Although the frequency difference between the machine and the network still meets the grid connection conditions, the phase angle difference subsequently exceeds the set value range and no longer meets the phase angle difference grid connection conditions. Therefore, this grid connection period is t∈[0,0.062]s, and the grid connection duration is 0.062s. When t=T3(0)=7.097s, the phase angle difference meets the conditions again, and at the same time, the frequency difference also meets the conditions. At this time, the frequency difference between the machine and the network has reached the lower limit of the set value -Δf. Set After this, the frequency difference cannot meet the grid connection condition. Therefore, within t∈[7.097,7.159]s, there is another time period during which the synchronous condenser can be grid-connected, with a duration of 0.062s. In summary, the total duration of the two grid-connectable time periods is 0.124s. If the total delay T of the synchronous condenser's synchronizing device... dqIf the time difference is greater than 0.062s, although the synchronous relay has closed, the allowed grid connection time for the synchronous condenser has already exceeded the limit, and the synchronous condenser will not be able to connect to the grid successfully. Among all initial phase angle changes, the percentage of times the total grid connection time is less than 0.3s is 3.89%, meaning if T... dq If the time to grid connection is greater than 0.15 seconds (at least two grid-connectable time periods), then the grid connection success rate is no higher than 96.11%.

[0142] Example 5

[0143] A system for calculating the success rate of synchronous grid connection of synchronous condensers includes:

[0144] The acquisition module obtains the frequency difference setpoint Δf for synchronous grid connection of the synchronous condenser. Set Phase angle difference setting value ΔA Set slip and the initial phase angle difference ΔA0;

[0145] The calculation module calculates the start, end, and duration of each grid-connected time period under different initial phase angle differences, as well as the number of grid-connected time periods, based on the information collected by the acquisition module, and then calculates the total grid-connected time.

[0146] The discrimination module determines the time by comparing the duration of each grid connection period with the synchronous condenser's action delay time T. dq Compare them.

[0147] Furthermore, the start and end points of the grid connection period and the calculation method for the grid connection period are as follows:

[0148] To simplify calculations and facilitate expression, the following symbols are defined:

[0149] In the formula, This represents the definition of mathematical symbols, where T1(n) and T2(n) respectively represent the mathematical symbols used in mathematical notation. The start and end points of grid connection within the time period, T3(n) and T4(n) respectively represent the start and end points of grid connection within the time period. The grid connection time start and end points within the time period, λ1(n) and λ2(n) are mathematical expressions defined for simplified representation. Indicates rounding down to the nearest integer. Let λ1(n) and λ2(n) represent the largest integers that can be obtained when λ1(n) and λ2(n) are greater than 0, respectively, where n is an integer; in the formula, ∪ represents the union of sets. Indicates n=1 to The merge operation of each set, Indicates n=2 to The merge operation of each set;

[0150] (1) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0151]

[0152] (2) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0153]

[0154] (3) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0155]

[0156] (4) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0157]

[0158] (5) When And ΔA0+ΔA Set <360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0159]

[0160] (6) When And ΔA0+ΔA Set >360 and ΔA0-ΔA Set When >0, The start and end points of the grid connection period, as well as the grid connection time period, are as follows:

[0161]

[0162] (7) When At that time, the synchronous condenser did not have a time period available for grid connection, and grid connection failed.

[0163] Furthermore, the method for calculating the total grid-connectable time is as follows:

[0164] (1) When and The total grid connection time is calculated as follows:

[0165] (2) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0166] (3) When and The total grid connection time is calculated as follows:

[0167] (4) When And ΔA0>ΔA Set The total grid connection time is calculated as follows:

[0168] (5) When At that time, the total time for the synchronous condenser to be connected to the grid is 0.

[0169] Furthermore, the discrimination module determines the time by comparing the duration of each grid connection period with the synchronous condenser's action delay time T. dq The comparison yields the grid connection success rate, including:

[0170] By comparing the duration of each grid connection period with the synchronous condenser action delay time T dq Comparisons were made, and the duration of each grid-connected time period under different initial phase angle differences ΔA0 was calculated to be no less than T. dq The proportion of this is the grid connection success rate.

[0171] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for calculating the success rate of synchronous grid connection of a synchronous condenser, characterized in that, include: The frequency difference setpoint for synchronous grid connection of the acquisition phase condenser Phase angle difference setting value and slip Calculate the difference of different initial phase angles The start, end, and duration of each grid connection time period; the duration of each grid connection time period and the synchronous condenser operation delay time. By comparing the results, the grid connection success rate can be obtained; The grid connection success rate is calculated as follows: the initial phase angle difference between 0° and 360°. Within the range of values, determine whether there is a duration of not less than [a certain duration] in the corresponding grid-connectable time period. The time period corresponding to Subrange; calculate the The ratio of the total angular span of the sub-range to 360° is used as the grid connection success rate.

2. The method for calculating the success rate of synchronous grid connection of synchronous condensers according to claim 1, characterized in that, The start and end points of the grid connection period and the calculation method for the grid connection period are as follows: To simplify calculations and facilitate expression, the following symbols are defined: , , , , , , , In the formula, This represents the definition of mathematical symbols. They represent in The start and end points of grid connection within the time period. They represent in The start and end points of grid connection within the time period. These are mathematical expressions defined for the purpose of simplification. Indicates rounding down to the nearest integer. They represent The largest integer that can be obtained when the result is greater than 0. Represents an integer; To represent the union of sets, Indicates n=1 to The merge operation of each set, Indicates n=2 to The merge operation of each set; (1) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (2) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (3) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (4) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (5) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (6) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (7) When The camera condenser does not have a time period available for grid connection, so grid connection was unsuccessful.

3. The method for calculating the success rate of synchronous grid connection of synchronous condensers according to claim 2, characterized in that, The calculation method for the duration of each grid connection time period is as follows: (1) When and The total grid connection time is calculated as follows: ; (2) When and The total grid connection time is calculated as follows: ; (3) When and The total grid connection time is calculated as follows: ; (4) When and The total grid connection time is calculated as follows: ; (5) When At that time, the total time for the synchronous condenser to be connected to the grid is 0.

4. A calculation system for the success rate of synchronous grid connection of synchronous condensers, characterized in that, include: The acquisition module obtains the frequency difference setpoint for synchronous grid connection of the synchronous condenser. Phase angle difference setting value slip and initial phase angle difference ; The calculation module calculates the start point, end point, and duration of each grid-connected time period under different initial phase angle differences, based on the information collected by the acquisition module. The discrimination module determines the time difference between the duration of each grid connection period and the delay time of the synchronous condenser action. By comparing the results, the grid connection success rate can be obtained; The grid connection success rate is calculated as follows: the initial phase angle difference between 0° and 360°. Within the range of values, determine whether there is a duration of not less than [a certain duration] in the corresponding grid-connectable time period. The time period corresponding to Subrange; calculate the The ratio of the total angular span of the sub-range to 360° is used as the grid connection success rate.

5. The system for calculating the success rate of synchronous grid connection of synchronous condensers according to claim 4, characterized in that, The start and end points of the grid connection period and the calculation method for the grid connection period are as follows: To simplify calculations and facilitate expression, the following symbols are defined: , , , , , , , In the formula, This represents the definition of mathematical symbols. They represent in The start and end points of grid connection within the time period. They represent in The start and end points of grid connection within the time period. These are mathematical expressions defined for the purpose of simplification. Indicates rounding down to the nearest integer. They represent The largest integer that can be obtained when the result is greater than 0. Represents an integer; To represent the union of sets, Indicates n=1 to The merge operation of each set, Indicates n=2 to The merge operation of each set; (1) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (2) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (3) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (4) When and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (5) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (6) When and and hour, The start and end points of the grid connection period, as well as the grid connection time period, are as follows: (7) When The camera condenser does not have a time period available for grid connection, so grid connection was unsuccessful.

6. The system for calculating the success rate of synchronous grid connection of synchronous condensers according to claim 5, characterized in that, The calculation method for the duration of each grid connection time period is as follows: (1) When and The total grid connection time is calculated as follows: ; (2) When and The total grid connection time is calculated as follows: ; (3) When and The total grid connection time is calculated as follows: ; (4) When and The total grid connection time is calculated as follows: ; (5) When At that time, the total time for the synchronous condenser to be connected to the grid is 0.

Images