Active power regulation method and system for extra-high voltage direct current transmission channel failure

Abstract

The present application relates to a kind of active regulation method and system for extra-high voltage direct current transmission channel fault, comprising: the active control amount of sending end power grid is determined according to the frequency deviation value of sending end power grid;According to the adjustable margin of specified extra-high voltage direct current transmission channel and the active control amount of sending end power grid, the active regulation of specified extra-high voltage direct current transmission channel is carried out in the order of active / frequency sensitivity from big to small;When the active control amount of sending end power grid still has surplus after the active regulation of specified extra-high voltage direct current transmission channel, then continue to carry out the active regulation of new energy power station and / or conventional unit in sending end power grid according to preset regulation priority.The present application compared with traditional fault regulation method, extra-high voltage direct current transmission channel and new energy power station are included in the regulation target, under the condition of meeting the active control demand of sending end power grid, still can reduce the conventional unit outage of sending end power grid, improve the frequency modulation efficiency of sending end power grid, more conducive to the stable operation of system after fault.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of direct current power transmission participating system frequency modulation, in particular to an active power regulation method and system for fault of an ultra-high voltage direct current power transmission channel. BACKGROUND

[0002] The wind and light resources in China and the load center present obvious inverse distribution characteristics, and large-scale long-distance power transmission is an important measure to solve the contradiction between energy and load distribution in China.

[0003] The ultra-high voltage direct current power transmission system has high voltage level and large power transmission capacity, and under the current technical conditions, it is a relatively appropriate choice for long-distance transmission of large-scale new energy power. At present, China has constructed multiple ultra-high voltage direct current power transmission channels to bundle the new energy power and thermal power in the west to the load center.

[0004] However, the construction of a large number of ultra-high voltage direct current projects increases the risk of serious power disturbance of the sending end power grid, and as the installed capacity of new energy continues to increase, the sending end power grid gradually presents the characteristics of high proportion of new energy installed capacity and relatively small proportion of supporting thermal power, which is a weakly synchronous support. A large amount of new energy power generation access significantly reduces the inertia level of the sending end system, further weakens the frequency modulation capability of the system, and increases the risk of serious frequency deviation of the sending end power grid.

[0005] Especially when the ultra-high voltage external transmission channel loses the power transmission capability caused by direct current fault such as direct current blocking, it will cause a large capacity power surplus in the sending end system, and the sending end system is prone to a large frequency deviation.

[0006] The frequency deviation caused by power surplus is a high frequency problem. At present, when the frequency of the sending end power grid deviates, the frequency is adjusted through the frequency modulation capability of the conventional unit (thermal power, water power, etc. The proportion of water power is usually very low, mainly thermal power). When the frequency deviation is too large, the conventional power supply will be cut off due to high frequency, which will further reduce the proportion of conventional power supply in the system, thereby reducing the frequency modulation capability and system inertia of the power grid, and further increasing the risk of frequency problems of the sending end power grid. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide an active power regulation method for fault of an ultra-high voltage direct current power transmission channel. Compared with the traditional fault regulation method, the method includes the ultra-high voltage direct current power transmission channel and the new energy power station in the regulation target, reduces the amount of conventional unit tripping of the sending end power grid under the condition of meeting the active power control demand of the sending end power grid, improves the frequency modulation efficiency of the sending end power grid, and is more conducive to the stable operation of the system after the fault.

[0008] The purpose of the present application is achieved by using the following technical scheme:

[0009] The application provides an active power regulation method for an UHVDC transmission channel fault, which is improved in that the method comprises the following steps:

[0010] determining an active power control amount of the sending-end power grid according to the frequency deviation value of the sending-end power grid;

[0011] performing active power regulation on the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid in descending order of active power / frequency sensitivity;

[0012] wherein the specified UHVDC transmission channel is a non-faulty UHVDC transmission channel connected to the same receiving-end power grid and the same sending-end power grid as the faulty UHVDC transmission channel.

[0013] Preferably, after the step of performing active power regulation on the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid in descending order of active power / frequency sensitivity, the method further comprises the following steps:

[0014] when the active power control amount of the sending-end power grid still has a remaining amount, continuing to perform active power regulation on the new energy power station and / or the conventional unit in the sending-end power grid according to a preset regulation priority;

[0015] wherein the preset regulation priority of the first type of new energy power station in the sending-end power grid, the second type of new energy power station in the sending-end power grid and the conventional unit in the sending-end power grid decreases in turn;

[0016] the first type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output is in an ascending phase within a preset time period;

[0017] the second type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output is not in an ascending phase within a preset time period;

[0018] the starting time of the preset time period is the fault time of the UHVDC transmission channel, and the length of the preset time period is Φ, which is a positive number.

[0019] The application provides an active power regulation system for a UHVDC transmission channel fault, which is characterized in that the system comprises the following:

[0020] a determination module for determining an active power control amount of the sending-end power grid according to the frequency deviation value of the sending-end power grid;

[0021] a first regulation module for performing active power regulation on the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid in descending order of active power / frequency sensitivity;

[0022] The specified UHVDC transmission channel is a non-faulty UHVDC transmission channel connected with the same receiving end power grid and the same sending end power grid as the faulty UHVDC transmission channel.

[0023] Preferably, the system further comprises:

[0024] The second regulation module is configured to, when there is still a surplus of the active power control amount of the sending end power grid after the active power regulation on the specified UHVDC transmission channel, continue to regulate the active power of the new energy power station and / or the conventional unit in the sending end power grid according to the preset regulation priority.

[0025] The preset regulation priority of the first type of new energy power station in the sending end power grid, the second type of new energy power station in the sending end power grid, and the conventional unit in the sending end power grid decreases in turn.

[0026] The first type of new energy power station in the sending end power grid is a new energy power station in the sending end power grid whose predicted output is in an ascending phase within a preset time period.

[0027] The second type of new energy power station in the sending end power grid is a new energy power station in the sending end power grid whose predicted output is not in an ascending phase within a preset time period.

[0028] The starting time of the preset time period is the time of the fault of the UHVDC transmission channel, and the length of the preset time period is Φ, which is a positive number.

[0029] Compared with the closest prior art, the present application has the beneficial effects that:

[0030] The technical scheme provided by the present application determines the active power control amount of the sending end power grid according to the frequency deviation value of the sending end power grid, regulates the active power of the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending end power grid in the order of decreasing active / frequency sensitivity, and continues to regulate the active power of the new energy power station and / or the conventional unit in the sending end power grid according to the preset regulation priority when there is still a surplus of the active power control amount of the sending end power grid after the active power regulation on the specified UHVDC transmission channel. Compared with the conventional fault regulation method, the UHVDC transmission channel and the new energy power station are included in the regulation target, the conventional unit cutting amount of the sending end power grid is reduced, the frequency regulation efficiency of the sending end power grid is improved, and the stable operation of the system after the fault is more beneficial.

[0031] The technical scheme provided by the present application considers the generation unit off-grid situation of the new energy power station in the sending end power grid caused by the fault of the UHVDC transmission channel, can more accurately obtain the active power control demand of the sending end power grid, and avoids unnecessary active power control.

[0032] The technical scheme provided by the application adopts the extra-high voltage direct current transmission system to assist the sending end power grid to solve the high frequency problem, so as to realize the purpose of quickly stabilizing the power surplus of the sending end power grid and the power deficiency of the receiving end power grid.

[0033] The technical scheme provided by the application, in the new energy power station participating in the regulation and control stage, preferably regulates and controls the new energy power station whose output power is in the rising stage in the ultra-short period after the fault, so as to reduce the risk of power surplus of the sending end power grid again. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is an active regulation method flow chart for the extra-high voltage direct current transmission channel fault;

[0035] Figure 2 is an active regulation system structure diagram for the extra-high voltage direct current transmission channel fault. DETAILED DESCRIPTION

[0036] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings.

[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0038] In the sending end power grid containing large-scale new energy power generation and extra-high voltage direct current transmission channel, when the extra-high voltage direct current transmission channel fails, the sending end power grid power surplus will be caused, so as to further cause the frequency of the sending end power grid to rise. At this time, the output level of the sending end power grid containing large-scale new energy power generation needs to be reduced, so that the frequency of the sending end power grid returns to the steady state. However, the extra-high voltage direct current transmission channel failure will cause serious frequency deviation of the sending end power grid, which is easy to trigger the high frequency machine tripping strategy of the sending end power grid, and then realize the frequency control of the sending end power grid. However, this will inevitably reduce the proportion of conventional units such as thermal power units in the sending end power grid (increase the proportion of new energy units in the sending end power grid), so as to reduce the stability level of the sending end power grid and increase the risk of frequency instability of the sending end power grid.

[0039] Based on this, the application provides an active regulation method for the extra-high voltage direct current transmission channel fault, such as Figure 1As shown, the method makes the non-faulty UHVDC transmission channel connecting the same receiving end power grid and the same sending end power grid as the faulty UHVDC transmission channel, a new energy power station participate in the regulation and control when the UHVDC transmission channel fails, so as to reduce the amount of conventional unit tripping of the receiving end power grid as much as possible, reduce the imbalance degree of the sending end power grid, reduce the active power surplus probability of the sending end power grid in a short time, reduce the regulation and control quantity of the non-faulty UHVDC transmission channel and reduce the regulation and control quantity of the new energy power station, and the method comprises:

[0040] Step 101, determining the active control quantity of the sending end power grid according to the frequency deviation value of the sending end power grid;

[0041] Step 102, according to the adjustable margin of the specified UHVDC transmission channel and the active control quantity of the sending end power grid, the active power is regulated and controlled in the order of active power / frequency sensitivity from large to small;

[0042] Among them, the specified UHVDC transmission channel is the non-faulty UHVDC transmission channel connecting the same receiving end power grid and the same sending end power grid as the faulty UHVDC transmission channel.

[0043] In the best embodiment of the application, when the UHVDC transmission system has multiple UHVDC transmission channels available for regulation and control, the non-faulty UHVDC transmission channel connecting the same sending end power grid and the same receiving end power grid as the faulty UHVDC transmission channel should be selected for active power regulation and control, so as to achieve the purpose of quickly stabilizing the power surplus of the sending end power grid and the power deficiency of the receiving end power grid.

[0044] Specifically, after the active power of the specified UHVDC transmission channel is regulated and controlled according to the adjustable margin of the specified UHVDC transmission channel and the active control quantity of the sending end power grid in the order of active power / frequency sensitivity from large to small, it further comprises:

[0045] Step 103, when the active control quantity of the sending end power grid still has a remaining quantity, the active power of the new energy power station and / or the conventional unit in the sending end power grid is further regulated and controlled according to the preset regulation and control priority;

[0046] Among them, the preset regulation and control priority of the first type of new energy power station in the sending end power grid, the second type of new energy power station in the sending end power grid and the conventional unit in the sending end power grid decreases in turn;

[0047] The first type of new energy power station in the sending end power grid is a new energy power station in the sending end power grid whose predicted output is in the rising stage within a preset period;

[0048] The second type of new energy power station in the sending end power grid is a new energy power station in the sending end power grid whose predicted output is not in the rising stage within a preset period;

[0049] The starting time of the preset time period is the fault time of the UHV DC transmission channel, and the length of the preset time period is Φ, which is a positive number.

[0050] In the best embodiment of the present application, the participation of the new energy power station in the emergency regulation of the UHV DC transmission channel fault can reduce the amount of conventional power source tripping and improve the stability of the post-fault sending end power grid.

[0051] The starting time of the preset time period is the fault time of the UHV DC transmission channel, and the length of the preset time period is Φ, which is a positive number, and can be set to 15 minutes.

[0052] When the UHV DC transmission system fails, such as DC blocking, the main problem faced by the sending end power grid is the active surplus and frequency deviation problem;

[0053] To solve the high frequency problem of the sending end power grid and ensure the stable operation of the sending end power grid, the active power output of the sending end power grid needs to be reduced according to the active control demand of the sending end power grid;

[0054] For a traditional power system, the active control demand of the power grid corresponding to a specific transmission channel fault can be solved based on the frequency deviation of the power system only, but for a sending end power grid with large-scale new energy power generation, the new energy off-grid situation during the UHV DC transmission channel fault also needs to be considered; therefore, the active control amount P of the sending end power grid is determined as follows: c

[0055]

[0056] In the above formula, Δf is the frequency deviation value of the sending end power grid, μ0 is the active-frequency sensitivity of the sending end power grid, p k is the output of the kth new energy power station in the sending end power grid before the UHV DC transmission channel fault, λ k is the off-grid proportion of the generating unit of the kth new energy power station in the sending end power grid caused by the UHV DC transmission channel fault, k ∈ (1~L), and L is the total number of new energy power stations in the sending end power grid;

[0057] In the best embodiment of the present application, the off-grid situation of the generating unit of the new energy power station in the sending end power grid caused by the UHV DC transmission channel fault is considered, so that the active control demand of the sending end power grid can be more accurately obtained, and unnecessary active control can be avoided.

[0058] Wherein, the frequency deviation value Δf of the sending end power grid is determined as follows:

[0059] Δf = f max - f y

[0060] ​In the above formula, f max This is the maximum frequency that the sending-end grid frequency can reach without control measures after a fault in an ultra-high voltage direct current (UHVDC) transmission channel. This value is obtained through simulation, f. y To reach the high-frequency switching threshold, the power grid frequency value at the sending end;

[0061] The active power-frequency sensitivity μ0 of the sending-end power grid is determined by the following formula:

[0062]

[0063] In the above formula, Δf * ΔP represents the frequency variation of the sending-end power grid. * This is the change in active power corresponding to the frequency change of the sending-end power grid.

[0064] In the preferred embodiment of the present invention, the new energy power station in the sending-end power grid is equipped with a monitoring and control system, which can obtain information such as the number of new energy power station units connected to the grid, the number of new energy power stations disconnected from the grid due to faults, and the output change information of new energy power stations.

[0065] Specifically, step 102 includes:

[0066] Step 102-1: Let i = 1, and sort the designated UHVDC transmission channels in descending order of active power / frequency sensitivity;

[0067] Step 102-2: If the adjustable margin p of the i-th specified UHVDC transmission channel in the sequence i 'Less than P' c Then the transmission capacity of the i-th designated UHVDC transmission channel is adjusted to p. i '+P i Otherwise, adjust the transmission capacity of the i-th designated UHVDC transmission channel to P. c +P i ;

[0068] Step 102-3: Update P according to the following formula c ,

[0069] Step 102-4: If P c ≠0 and i≠S n If so, let i = i + 1, and return to step 2; if P c ≠0 and i=S n Then let the residual amount P of the active power control quantity of the sending-end grid after active power regulation of the designated UHVDC transmission channel be... c * =P c Otherwise, let the remaining amount P of the active power control quantity of the sending-end grid after active power regulation of the designated UHVDC transmission channel be...c * = 0;

[0070] wherein, P c is the active power control amount of the sending end power grid, i ∈ (1 ~ S n ), S n is the total number of specified UHVDC transmission channels, P i is the transmission capacity of the i-th specified UHVDC transmission channel in the sequence before the fault of the UHVDC transmission channel, μ i is the active power / frequency sensitivity of the i-th specified UHVDC transmission channel in the sequence, and μ0 is the active power / frequency sensitivity of the sending end power grid.

[0071] In the preferred embodiment of the present application, the surplus power transmission capacity of the specified UHVDC transmission channel is utilized to quickly increase the power transmission of the transmission channel under the premise of meeting the operation stability of the specified UHVDC transmission channel, reduce the active power control demand of the sending end power grid, reduce the amount of generator tripping of the sending end power grid, and ensure the power demand of the receiving end power grid, thereby playing a function of supporting system frequency regulation.

[0072] In the preferred embodiment of the present application, the frequency change amount of the system after the active power disturbance is related to the active power disturbance amount, and the UHVDC transmission system is utilized to assist the sending end power grid to solve the high frequency problem, and the transmission capacity of the specified UHVDC transmission channel needs to be increased (equivalent to reducing the equivalent active power disturbance amount) to reduce the active power surplus of the sending end power grid and balance the power generation and load of the sending end power grid.

[0073] However, while considering the frequency safety of the sending end power grid, the transient voltage safety and transient stability of the sending end power grid should be taken into account, and the transmission capacity of the specified UHVDC transmission channel should not exceed the upper limit of the transmission capacity.

[0074] Meanwhile, the frequent regulation and control of the UHVDC transmission channel will also affect the operation of the UHVDC transmission system and the service life of the equipment, and the regulation and control amount of the UHVDC transmission system should be minimized as much as possible.

[0075] And for the same active power transmission capacity, the specified UHVDC transmission channel with high active power / frequency sensitivity has a better response effect on the system frequency than the specified UHVDC transmission channel with low active power / frequency sensitivity.

[0076] Therefore, the present application sets the regulation and control priority order of the specified UHVDC transmission channel in the order from high to low active power / frequency sensitivity, adopts the method of cooperative regulation and control of multiple specified UHVDC transmission channels, and sequentially improves the transmission capacity of the specified UHVDC transmission channel.

[0077] In the regulation and control process, the following constraint conditions need to be met:

[0078] ft,max ≤f 1m

[0079] V min ≤V j ≤V max

[0080] δ t,max ≤δ 1m

[0081] P DC，i ≤P DC，1m

[0082] In the above formula, f t,max is the maximum frequency of the sending end power grid, f 1m is the maximum upper limit of the frequency allowed by the sending end power grid, V j is the voltage of node j in the sending end power grid, V max is the upper limit value of the voltage of the node in the sending end power grid, V min is the lower limit value of the voltage of the node in the sending end power grid, δ 1m is the attack angle difference threshold value in the sending end power grid, δ t,max is the maximum attack angle difference in the sending end power grid, P DC，1m is the upper limit value of the transmission capacity of the UHVDC transmission channel, P DC，i is the transmission capacity of the i-th specified UHVDC transmission channel.

[0083] Further, the μ i is obtained by the following process:

[0084] In the UHVDC transmission system simulation environment, set the Q-group transmission capacity values of the i-th specified UHVDC transmission channel, and record the frequency values of the receiving end power grid in the UHVDC transmission system simulation environment corresponding to the Q-group transmission capacity values respectively;

[0085] Based on the Q-group transmission capacity values and the frequency values of the receiving end power grid in the UHVDC transmission system simulation environment corresponding to the Q-group transmission capacity values respectively, fit a function relationship formula with the transmission capacity value as the independent variable and the frequency value of the receiving end power grid as the dependent variable;

[0086] Take the partial derivative of the independent variable in the function relationship formula to obtain the μ i ;

[0087] Wherein, Q is the total number of preset experimental data groups.

[0088] Specifically, the step 103 comprises:

[0089] Step 103-1: Active power regulation is performed on the first type of new energy power station in the sending end power grid in ascending order of the predicted power output amplitude rising value within a preset time period, and the residual amount P of the active power control amount of the sending end power grid after the active power regulation on the first type of new energy power station in the sending end power grid is obtained c T ;

[0090] In the preferred embodiment of the present application, due to the fluctuation of the output of the new energy power station, when the UHVDC transmission channel fails, the output of some new energy power stations is in the rising stage, the output of some new energy power stations is in the falling stage, and the output of some new energy power stations is relatively stable.

[0091] If the removed new energy power station is not reasonably selected, it is possible that the output of the unremoved new energy power station is in the rising stage, causing the sending end power grid to have power surplus again.

[0092] To solve this problem, the output variation trend of each related new energy power station should be determined according to the real-time output data and the output of the ultra-short-term prediction of the new energy power station;

[0093] It is preferred to select the new energy power station whose output is in the rising stage within the Φ time period after the failure for generator tripping, so as to reduce the risk of power surplus of the sending end power grid again.

[0094] Step 103-2: When P c T is not 0, active power regulation is performed on the second type of new energy power station in the sending end power grid, and the residual amount P of the active power control amount of the sending end power grid after the active power regulation on the second type of new energy power station in the sending end power grid is obtained c Z ;

[0095] In the preferred embodiment of the present application, the new energy power station whose output is not in the rising stage within the Φ time period after the failure is removed in proportion.

[0096] Step 103-3: When P c Z is not 0, the conventional generator unit in the sending end power grid is regulated by using the conventional generator unit high-frequency generator tripping strategy until the residual amount of the active power control amount of the sending end power grid is 0.

[0097] Further, the step 103-1 comprises:

[0098] Step 103-1-1: The first type of new energy power station in the sending end power grid is sorted in ascending order of the predicted power output amplitude rising value within a preset time period;

[0099] Step 103-1-2: If there is m satisfying The output of the first type new energy power station in the first to the m-1th in the regulation sequence is 0, and the output of the mth in the regulation sequence is Otherwise, the output of each first type new energy power station in the regulation sequence is 0.

[0100] Step 103-1-3: the remaining amount P of the active power control amount of the sending end power grid after the active power regulation of the first type new energy power station in the sending end power grid is obtained according to the following formula c T ;

[0101]

[0102] Wherein, P s,d is the predicted output of the dth first type new energy power station in the sequence, m ∈ (1 ~ S d ), S d is the total number of the first type new energy power station in the sending end power grid.

[0103] In the best embodiment of the present application, in order to minimize the amount of new energy power station tripping, the regulation sequence of the first type new energy power station should be set according to the output rise range within the Φ time after the fault.

[0104] Further, the step 103-2 comprises:

[0105] Step 103-2-1: if The output of the second type new energy power station in the sending end power grid is 0, otherwise, the output of the hth second type new energy power station in the sending end power grid is

[0106] Step 103-2-2: the remaining amount P of the active power control amount of the sending end power grid after the active power regulation of the second type new energy power station in the sending end power grid is obtained according to the following formula c Z ;

[0107]

[0108] Wherein, P w,h is the predicted output of the hth second type new energy power station in the sending end power grid, h ∈ (1 ~ S h ), S h is the total number of the hth second type new energy power station in the sending end power grid.

[0109] In the best embodiment of the present application, in order to ensure fairness, the power generation of the second type new energy power station should be cut off in proportion.

[0110] The present application provides an active power regulation system for the fault of an extra-high voltage direct current transmission channel, such as Figure 2 The system comprises:

[0111] determining a frequency deviation value of the sending-end power grid, and determining an active power control amount of the sending-end power grid according to the frequency deviation value of the sending-end power grid;

[0112] a first regulating module, configured to regulate the active power of the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid, and in a descending order of active power / frequency sensitivity;

[0113] The specified UHVDC transmission channel is a non-faulty UHVDC transmission channel connected to the same receiving-end power grid and the same sending-end power grid as the faulty UHVDC transmission channel.

[0114] Specifically, the system further comprises a second regulating module.

[0115] The second regulating module is configured to continue regulating the active power of the new energy power station and / or the conventional generating unit in the sending-end power grid according to a preset regulating priority when the active power control amount of the sending-end power grid still has a remaining amount.

[0116] The preset regulating priority of the first type of new energy power station in the sending-end power grid, the second type of new energy power station in the sending-end power grid, and the conventional generating unit in the sending-end power grid is in a descending order.

[0117] The first type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output is in an ascending phase within a preset time period.

[0118] The second type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output is not in an ascending phase within a preset time period.

[0119] The starting time of the preset time period is the time of the fault of the UHVDC transmission channel, and the length of the preset time period is Φ, which is a positive number.

[0120] Specifically, the determining module is configured to:

[0121] determine the active power control amount P of the sending-end power grid according to the following formula: c

[0122]

[0123] In the above formula, Δf is the frequency deviation value of the sending-end power grid, μ0 is the active power-frequency sensitivity of the sending-end power grid, P k is the output of the kth new energy power station in the sending-end power grid before the fault of the UHVDC transmission channel, λ k is the off-grid proportion of the power generation unit in the kth new energy power station in the sending-end power grid caused by the fault of the UHVDC transmission channel, k ∈ (1~L), and L is the total number of new energy power stations in the sending-end power grid.​

[0124] wherein the frequency deviation value Δf of the sending end power grid is determined as follows:

[0125] Δf = f max - f y

[0126] In the above formula, f max is the maximum value of the frequency of the sending end power grid without taking control measures after the fault of the UHV DC transmission channel, and f y is the frequency value of the sending end power grid when the high-frequency generator tripping threshold is reached.

[0127] The active-frequency sensitivity μ0 of the sending end power grid is determined as follows:

[0128]

[0129] In the above formula, Δf * is the frequency change value of the sending end power grid, and ΔP * is the active change value corresponding to the frequency change value of the sending end power grid.

[0130] Specifically, the first regulation module comprises:

[0131] a sorting unit configured to set i = 1 and sort the specified UHV DC transmission channels in descending order of the active-frequency sensitivity;

[0132] a first regulation unit configured to, if the adjustable margin p i of the i-th specified UHV DC transmission channel in the sequence is less than P c , regulate the transmission capacity of the i-th specified UHV DC transmission channel to p i + P i ; otherwise, regulate the transmission capacity of the i-th specified UHV DC transmission channel to P c + P i .

[0133] an updating unit configured to update P c according to the following formula:

[0134] a command unit configured to, if P c ≠ 0 and i ≠ S n , set i = i + 1 and return to step 2; if P c ≠ 0 and i = S n , regulate the transmission capacity of the i-th specified UHV DC transmission channel to P c * + P c; otherwise, let the remaining amount P c * = 0.

[0135] wherein P c is the active control amount of the sending end power grid, i ∈ (1 ~ S n ), S n is the total number of specified UHVDC transmission channels, P i is the transmission capacity of the i-th specified UHVDC transmission channel in the sequence before the UHVDC transmission channel fault, μ i is the active / frequency sensitivity of the i-th specified UHVDC transmission channel in the sequence, and μ0 is the active / frequency sensitivity of the sending end power grid.

[0136] Further, the process of obtaining the μ i includes:

[0137] setting the Q-group transmission capacity value of the i-th specified UHVDC transmission channel in the UHVDC system simulation environment, and recording the frequency value of the receiving end power grid in the UHVDC system simulation environment corresponding to the Q-group transmission capacity value respectively;

[0138] fitting a functional relationship formula with the transmission capacity value as the independent variable and the frequency value of the receiving end power grid as the dependent variable based on the Q-group transmission capacity value and the frequency value of the receiving end power grid in the UHVDC system simulation environment corresponding to the Q-group transmission capacity value respectively;

[0139] taking the partial derivative of the independent variable in the functional relationship formula to obtain the μ i ;

[0140] wherein Q is the total number of preset experimental data groups.

[0141] Further, the second control unit includes:

[0142] The second control unit is configured to perform active regulation on the first type of new energy power station in the sending end power grid in descending order of the predicted output amplitude rise value in a preset time period, and obtain the remaining amount P c T of the active control amount of the sending end power grid after the active regulation on the first type of new energy power station in the sending end power grid.

[0143] The third control unit is configured to perform active regulation on the second type of new energy power station in the sending end power grid when P c T is not 0, and obtain the remaining amount P c Z of the active control amount of the sending end power grid after the active regulation on the second type of new energy power station in the sending end power grid.

[0144] The fourth regulating unit is configured to regulate the output of the conventional generating units in the sending end power grid according to a conventional generating unit high-frequency tripping strategy when P c Z is not 0, the conventional generating unit high-frequency tripping strategy is adopted to regulate the output of the conventional generating units in the sending end power grid until the residual amount of the active power control amount of the sending end power grid is 0.

[0145] Further, the second regulating unit comprises:

[0146] The sorting sub-unit is configured to sort the first type of new energy power stations in the sending end power grid in descending order according to the predicted output amplitude rising values in the preset time period.

[0147] The first regulating sub-unit is configured to regulate the output of the first type of new energy power stations in the sending end power grid according to the following rules: If there is m satisfying , the output of the first m-1 first type of new energy power stations in the sequence is 0, and the output of the mth first type of new energy power station in the sequence is Otherwise, the output of each first type of new energy power station in the sequence is 0.

[0148] The first obtaining sub-unit is configured to obtain the residual amount P of the active power control amount of the sending end power grid after the active power regulation of the first type of new energy power stations in the sending end power grid according to the following formula: c T ;

[0149]

[0150] , wherein P s,d is the predicted output of the dth first type of new energy power station in the sequence, m ∈ (1 ~ S d ), S d is the total number of the first type of new energy power stations in the sending end power grid.

[0151] Further, the third regulating unit comprises:

[0152] The second regulating sub-unit is configured to regulate the output of the second type of new energy power stations in the sending end power grid according to the following rules: If , the output of each second type of new energy power station in the sending end power grid is 0, otherwise, the output of the hth second type of new energy power station in the sending end power grid is

[0153] The second obtaining sub-unit is configured to obtain the residual amount P of the active power control amount of the sending end power grid after the active power regulation of the second type of new energy power stations in the sending end power grid according to the following formula: c Z ;

[0154]

[0155] , wherein P w,h is the predicted output of the hth second type of new energy power station in the sending end power grid, h ∈ (1 ~ Sh ), S h is the total number of the hth second-type new energy power station in the sending end power grid.

[0156] Those skilled in the art will understand that embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) containing computer usable program code.

[0157] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in the flowcharts and / or block diagrams.

[0158] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in the flowcharts and / or block diagrams.

[0159] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, so that a series of operation steps are performed on the computer or other programmable data processing apparatus to produce a computer-implemented process, so that the instructions executed on the computer or other programmable data processing apparatus provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that implements the functions specified in the flowcharts and / or block diagrams.

[0160] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A method for active power regulation in case of a fault in an UHVDC transmission channel, characterized in that, The method comprises: determining an active power control amount of the sending-end power grid according to the frequency deviation value of the sending-end power grid; controlling the active power of the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid in descending order of the active power / frequency sensitivity; wherein the specified UHVDC transmission channel is a non-faulty UHVDC transmission channel connected to the same receiving-end power grid and the same sending-end power grid as the faulty UHVDC transmission channel; the determination of the active power control amount of the sending-end power grid according to the frequency deviation value of the sending-end power grid comprises: The active control quantity P of the sending end power grid is determined according to the following formula c : In the above formula, Δf is the frequency deviation value of the sending-end power grid, μ0 is the active-frequency sensitivity of the sending-end power grid, p k is the output of the kth new energy power station in the sending-end power grid before the fault of the UHV DC transmission channel, λ k is the off-grid proportion of the generating unit in the kth new energy power station in the sending-end power grid caused by the fault of the UHV DC transmission channel, k ∈ (1~L), L is the total number of new energy power stations in the sending-end power grid; wherein the frequency deviation value Δf of the sending-end power grid is determined according to the following formula: Δf = f max -f y In the above formula, f max is the maximum value of the sending-end power grid frequency that can be reached after a fault in an extra-high voltage direct current transmission channel without taking control measures, f y is the sending-end power grid frequency value when the high-frequency generator tripping threshold is reached. the active power / frequency sensitivity μ0 of the sending-end power grid is determined according to the following formula: In the above equation, Δf * is the frequency change value of the sending end power grid, and ΔP * is the active power change value corresponding to the frequency change value of the sending end power grid.

2. The method of claim 1, wherein, after the controlling of the active power of the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid in descending order of the active power / frequency sensitivity, the method further comprises: when the active power control amount of the sending-end power grid still has a remaining amount, the new energy power station and / or the conventional unit in the sending-end power grid are further controlled according to a preset control priority; wherein the preset control priority of the first type of new energy power station in the sending-end power grid, the second type of new energy power station in the sending-end power grid and the conventional unit in the sending-end power grid is in descending order; the first type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output power is in an ascending phase within a preset time period; the second type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output power is not in an ascending phase within a preset time period; the starting time of the preset time period is the time of the fault of the UHVDC transmission channel, and the length of the preset time period is Φ, which is a positive number.

3. The method of claim 1, wherein, the controlling of the active power of the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid in descending order of the active power / frequency sensitivity comprises: Step 1: Let i = 1, and sort the specified UHVDC transmission channels in descending order of the active power / frequency sensitivity; Step 2: If the adjustable margin p of the i-th specified UHVDC transmission channel in the sequence is less than P i , then the transmission capacity of the i-th specified UHVDC transmission channel is regulated to be p c + P i ; otherwise, the transmission capacity of the i-th specified UHVDC transmission channel is regulated to be P i + P c . i ​ Step 3: Update P as follows c , Step 4: if P≠0 and i≠S c n then let i=i+1 and return to Step 2; if P≠0 and i=S c n then let the remaining amount of the active control quantity of the sending-end power grid after active regulation of the specified UHVDC transmission channel otherwise, let the remaining amount of the active control quantity of the sending-end power grid after active regulation of the specified UHVDC transmission channel ​​ where P c is the active power control quantity of the sending-end power grid, i ∈ (1 ~ S n ), S n is the total number of specified UHVDC transmission channels, P i is the transmission capacity of the i-th specified UHVDC transmission channel in the sequence before the UHVDC transmission channel fault, μ i is the active power / frequency sensitivity of the i-th specified UHVDC transmission channel in the sequence, and μ0 is the active power / frequency sensitivity of the sending-end power grid.

4. The method of claim 3, wherein, The μ i The acquisition process includes: setting the Qth transmission capacity value of the ith specified UHVDC transmission channel in the UHVDC transmission system simulation environment, and recording the frequency values of the receiving-end power grid in the UHVDC transmission system simulation environment corresponding to the Qth transmission capacity value respectively; fitting a function relationship formula with the transmission capacity value as the independent variable and the frequency value of the receiving-end power grid as the dependent variable based on the Qth transmission capacity value and the frequency values of the receiving-end power grid in the UHVDC transmission system simulation environment corresponding to the Qth transmission capacity value respectively; Taking partial derivative of the independent variable in the function relationship, the μ i ; wherein Q is the total number of preset experimental data groups.

5. The method of claim 2, wherein, when the active power control amount of the sending-end power grid still has a remaining amount, the new energy power station and / or the conventional unit in the sending-end power grid are further controlled according to a preset control priority, which comprises: Step A: performing active regulation on the first type of new energy power station in the sending end power grid in the preset time period according to the predicted active power amplitude rise value in descending order, and obtaining the remaining amount of the active control amount of the sending end power grid after the active regulation on the first type of new energy power station in the sending end power grid Step B: when is not 0, active power regulation is performed on the second type of new energy power station in the sending end power grid, and a residual amount of the active power control amount of the sending end power grid after the active power regulation on the second type of new energy power station in the sending end power grid is obtained Step C: When If not 0, the conventional generating units in the sending terminal power grid are regulated by the conventional generating units high-frequency tripping strategy until the residual amount of the active power control amount of the sending terminal power grid is 0.

6. The method of claim 5, wherein, the step A comprises: Step A-1: sorting the first type of new energy power station in the sending-end power grid in descending order of the predicted output power amplitude ascending value within a preset time period; Step A-2: If there is m satisfying then the output of the first to the m-1th first-type new energy power station in the sequence is 0, and the output of the mth first-type new energy power station in the sequence is otherwise, the output of each first-type new energy power station in the sequence is 0. Step A-3: The remaining amount of the active power control amount of the sending end power grid after the active power regulation of the first type of new energy power station in the sending end power grid is obtained according to the following formula wherein P s,d is the predicted output of the dth first-type new energy power station in the sequence, m ∈ (1 ~ S d ), S d is the total number of first-type new energy power stations in the sending-end power grid.

7. The method of claim 5, wherein, the step B comprises: Step B-1: If then the output of the second type of new energy power station in the sending end power grid is 0, otherwise, the output of the hth second type of new energy power station in the sending end power grid is Step B-2: Get the remaining amount of active power control of the sending end power grid after the active power regulation of the second type of new energy power station in the sending end power grid wherein P w,h is the predicted output of the hth second-type new energy power station in the sending-end power grid, h ∈ (1 ~ S h ), S h is the total number of second-type new energy power stations in the sending-end power grid.

8. An active regulation system for an extra-high voltage direct current transmission channel in case of a fault, characterized in that the system is used for the method of claim 1, comprising: The determining module is configured to determine the active power control amount of the sending-end power grid according to the frequency deviation value of the sending-end power grid; The first regulating module is configured to regulate the active power of the specified UHVDC transmission channel according to the adjustable margin of the specified UHVDC transmission channel and the active power control amount of the sending-end power grid, in the order of the active power / frequency sensitivity from large to small. The specified UHVDC transmission channel is a non-faulty UHVDC transmission channel connected to the same receiving-end power grid and the same sending-end power grid as the faulty UHVDC transmission channel.

9. The system of claim 8, wherein, The system further comprises: The second regulating module is configured to continue regulating the active power of the new energy power station and / or the conventional generating unit in the sending-end power grid according to the preset regulating priority when the active power control amount of the sending-end power grid still has a remaining amount. The preset regulating priority of the first type of new energy power station in the sending-end power grid, the second type of new energy power station in the sending-end power grid, and the conventional generating unit in the sending-end power grid decreases in turn. The first type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output is in an ascending phase within a preset time period. The second type of new energy power station in the sending-end power grid is a new energy power station in the sending-end power grid whose predicted output is not in an ascending phase within a preset time period. The starting time of the preset time period is the time of the fault of the UHVDC transmission channel, and the length of the preset time period is Φ, which is a positive number.

Images