CN112165124A - Active power regulation and control method and system for fault of extra-high voltage direct current transmission channel - Google Patents
Active power regulation and control method and system for fault of extra-high voltage direct current transmission channel Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
Abstract
The invention relates to an active regulation and control method and system for an extra-high voltage direct current transmission channel during fault, which comprises the following steps: determining the active control quantity of the power grid of the transmitting end according to the frequency deviation value of the power grid of the transmitting end; according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid, performing active regulation and control on the specified extra-high voltage direct-current transmission channel according to the sequence of active/frequency sensitivity from large to small; and when the active control quantity of the power transmission end power grid still has surplus after the active regulation and control is carried out on the appointed extra-high voltage direct-current power transmission channel, the active regulation and control are continuously carried out on the new energy power station and/or the conventional unit in the power transmission end power grid according to the preset regulation and control priority. Compared with the traditional fault regulation and control method, the extra-high voltage direct current transmission channel and the new energy power station are brought into the regulation and control target, the conventional unit switching amount of the sending-end power grid can be reduced under the condition that the active control requirement of the sending-end power grid is met, the frequency modulation efficiency of the sending-end power grid is improved, and the stable operation of a system after the fault is facilitated.
Description
Technical Field
The invention relates to the technical field of direct current transmission participation system frequency modulation, in particular to an active power regulation and control method and system for ultrahigh voltage direct current transmission channel faults.
Background
The Chinese wind and light resources and load center present obvious inverse distribution characteristics, and large-scale long-distance power transmission is an important measure for solving the contradiction between energy and load distribution in China.
The extra-high voltage direct current transmission system is high in voltage level and large in transmission capacity, and is a more suitable choice for large-scale new energy power long-distance transmission under the current technical conditions. At present, China has built a plurality of extra-high voltage direct-current transmission channels, and western new energy electric power and thermal power are bundled and transmitted to a load center.
However, the construction of a large number of extra-high voltage direct current projects increases the risk that the transmission-end power grid suffers from serious power disturbance, and as the scale of the new energy installation machine is continuously increased, the transmission-end power grid gradually presents the characteristics of high installation occupation ratio of the new energy and relatively small matching thermal power occupation ratio of weak synchronous support, the inertia level of the transmission-end system is obviously reduced by the large number of new energy power generation accesses, the frequency modulation capability of the system is further weakened, and the risk that the transmission-end power grid suffers from serious frequency deviation is increased.
Particularly, when the extra-high voltage outgoing channel loses the power transmission capacity due to direct current faults such as direct current blocking and the like, the surplus of large-capacity power can be caused to a sending end system, and the sending end system is easy to have large frequency deviation.
The frequency deviation caused by surplus power is a high-frequency problem, when the frequency of a power grid at a sending end is deviated at present, the frequency is adjusted through the frequency modulation capability of a conventional unit (conventional power supplies such as thermal power and hydropower, generally, the proportion of water and electricity is very low, and mainly thermal power), when the frequency deviation is too large, the conventional power supplies are switched off due to high frequency, the proportion of the conventional power supplies in a system is further reduced, the frequency modulation capability and the system inertia of the power grid are reduced, and the risk of the frequency problem of the power grid at the sending end is further increased.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an active regulation and control method for the fault of an extra-high voltage direct current transmission channel.
The purpose of the invention is realized by adopting the following technical scheme:
the invention provides an active regulation and control method for an extra-high voltage direct current transmission channel during fault, and the improvement is that the method comprises the following steps:
determining the active control quantity of the power grid of the transmitting end according to the frequency deviation value of the power grid of the transmitting end;
according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid, performing active regulation and control on the specified extra-high voltage direct-current transmission channel according to the sequence of active/frequency sensitivity from large to small;
the designated extra-high voltage direct-current transmission channel is a non-fault extra-high voltage direct-current transmission channel which is connected with the same receiving-end power grid and the same transmitting-end power grid as the fault extra-high voltage direct-current transmission channel.
Preferably, after performing active regulation and control on the specified extra-high voltage direct current transmission channel according to the adjustable margin of the specified extra-high voltage direct current transmission channel and the active control quantity of the transmission end power grid and according to the sequence of active/frequency sensitivity from large to small, the method further includes:
when the active control quantity of the power grid at the transmitting end still has surplus, continuously carrying out active regulation and control on a new energy power station and/or a conventional unit in the power grid at the transmitting end according to a preset regulation and control priority;
the preset regulation and control priorities of a first type of new energy power station in a delivery-end power grid, a second type of new energy power station in the delivery-end power grid and a conventional unit in the delivery-end power grid are sequentially reduced;
the first type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is in an ascending stage in a preset time period in the sending-end power grid;
a second type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is not in a rising stage within a preset time period in the sending-end power grid;
the starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, and phi is a positive number.
The invention provides an active regulation and control system for an extra-high voltage direct current transmission channel during fault, which is characterized by comprising the following components:
the determining module is used for determining the active control quantity of the power grid of the transmitting end according to the frequency deviation value of the power grid of the transmitting end;
the first regulation and control module is used for carrying out active regulation and control on the specified extra-high voltage direct-current transmission channel according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid and the sequence of active/frequency sensitivity from large to small;
the designated extra-high voltage direct-current transmission channel is a non-fault extra-high voltage direct-current transmission channel which is connected with the same receiving-end power grid and the same transmitting-end power grid as the fault extra-high voltage direct-current transmission channel.
Preferably, the system further comprises:
the second regulation and control module is used for continuing to carry out active regulation and control on a new energy power station and/or a conventional unit in the transmission end power grid according to a preset regulation and control priority when the active control quantity of the transmission end power grid still has surplus after the active regulation and control is carried out on the appointed extra-high voltage direct-current transmission channel;
the preset regulation and control priorities of a first type of new energy power station in a delivery-end power grid, a second type of new energy power station in the delivery-end power grid and a conventional unit in the delivery-end power grid are sequentially reduced;
the first type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is in an ascending stage in a preset time period in the sending-end power grid;
a second type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is not in a rising stage within a preset time period in the sending-end power grid;
the starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, and phi is a positive number.
Compared with the closest prior art, the invention has the following beneficial effects:
according to the technical scheme provided by the invention, the active control quantity of the power grid of the sending end is determined according to the frequency deviation value of the power grid of the sending end; according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid, performing active regulation and control on the specified extra-high voltage direct-current transmission channel according to the sequence of active/frequency sensitivity from large to small; and when the active control quantity of the power transmission end power grid still has surplus after the active regulation and control is carried out on the appointed extra-high voltage direct-current power transmission channel, the active regulation and control are continuously carried out on the new energy power station and/or the conventional unit in the power transmission end power grid according to the preset regulation and control priority. Compared with the traditional fault regulation and control method, the extra-high voltage direct current transmission channel and the new energy power station are brought into a regulation and control target, the conventional unit machine switching amount of the power grid at the sending end can be reduced under the condition that the active control requirement of the power grid at the sending end is met, the frequency modulation efficiency of the power grid at the sending end is improved, and the stable operation of a system after the fault is facilitated.
According to the technical scheme provided by the invention, the condition that the power generation unit is disconnected due to the fault of the extra-high voltage direct current transmission channel of the new energy power station in the power grid at the transmitting end is considered, the active control requirement of the power grid at the transmitting end can be more accurately obtained, and unnecessary active control is avoided.
According to the technical scheme provided by the invention, the ultra-high voltage direct current transmission system is adopted to assist the sending-end power grid to solve the high-frequency problem, so that the purposes of quickly stabilizing the power excess of the sending-end power grid and the power shortage of the receiving-end power grid are achieved.
According to the technical scheme provided by the invention, in the stage that the new energy power station participates in regulation and control, the new energy power station with the output in the rising stage predicted in a super short term after the regulation and control fault is optimized, so that the risk of power surplus of the power grid at the transmitting end is reduced.
Drawings
FIG. 1 is a flow chart of an active power regulation method used in the case of an extra-high voltage direct current transmission channel fault;
fig. 2 is a structural diagram of an active regulation and control system used for an extra-high voltage direct-current transmission channel during fault.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In a transmitting end power grid operation scene containing large-scale new energy power generation and an extra-high voltage direct current transmission channel, when the extra-high voltage direct current transmission channel fails, the power surplus of the transmitting end power grid can be caused, so that the frequency of the transmitting end power grid is further increased, and at the moment, the output level of the transmitting end power grid containing large-scale new energy power generation needs to be reduced, so that the frequency of the transmitting end power grid is recovered to a stable state; however, the high-frequency generator tripping strategy of the transmission-end power grid is easily triggered to further realize the frequency control of the transmission-end power grid, but the occupation ratio of conventional units such as thermal power units in the transmission-end power grid is inevitably reduced (the occupation ratio of a new energy unit in the transmission-end power grid is improved), so that the stability level of the transmission-end power grid is reduced, and the frequency instability risk of the transmission-end power grid is increased.
Based on this, the invention provides an active regulation and control method for an extra-high voltage direct current transmission channel fault, as shown in fig. 1, the method enables a non-fault extra-high voltage direct current transmission channel and a new energy power station which are connected with a same receiving end power grid and a same transmitting end power grid with the fault extra-high voltage direct current transmission channel to participate in regulation and control of the extra-high voltage direct current transmission channel fault, so that the conventional unit switching amount of the receiving end power grid is reduced as much as possible, the supply and demand imbalance degree of the transmitting end power grid is reduced, the active secondary surplus probability of the transmitting end power grid in a short time is reduced, the regulation and control number of the non-fault extra-high voltage direct current transmission channel is reduced, and the regulation and control number of the new energy power station is reduced:
102, performing active regulation and control on the specified extra-high voltage direct-current transmission channel according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid in the order of the active/frequency sensitivity from large to small;
the designated extra-high voltage direct-current transmission channel is a non-fault extra-high voltage direct-current transmission channel which is connected with the same receiving-end power grid and the same transmitting-end power grid as the fault extra-high voltage direct-current transmission channel.
In the best embodiment of the invention, when the extra-high voltage direct current transmission system is provided with a plurality of extra-high voltage direct current transmission channels for regulation control, the non-fault extra-high voltage direct current transmission channel which is connected with the same transmitting-end power grid and the same receiving-end power grid as the fault extra-high voltage direct current transmission channel is selected for active regulation, so that the aims of quickly stabilizing the power surplus of the transmitting-end power grid and the power shortage of the receiving-end power grid are fulfilled.
Specifically, after performing active regulation and control on the specified extra-high voltage direct current transmission channel according to the adjustable margin of the specified extra-high voltage direct current transmission channel and the active control quantity of the transmission end power grid and according to the sequence of active/frequency sensitivity from large to small, the method further includes:
103, when the active control quantity of the power grid at the transmitting end still has surplus, continuing to perform active regulation and control on a new energy power station and/or a conventional unit in the power grid at the transmitting end according to a preset regulation and control priority;
the preset regulation and control priorities of a first type of new energy power station in a delivery-end power grid, a second type of new energy power station in the delivery-end power grid and a conventional unit in the delivery-end power grid are sequentially reduced;
the first type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is in an ascending stage in a preset time period in the sending-end power grid;
a second type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is not in a rising stage within a preset time period in the sending-end power grid;
the starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, and phi is a positive number.
In the best embodiment of the invention, the new energy power station participates in the emergency regulation and control when the extra-high voltage direct current transmission channel fails, so that the conventional power supply switching amount can be reduced, and the stability of a power grid at a sending end after the failure is improved.
The starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, the phi is a positive number, and the time interval can be set to be 15 minutes.
When an extra-high voltage direct current transmission channel is blocked due to faults such as direct current blocking and the like of an extra-high voltage direct current transmission system, the main problems of the transmission end power grid are the problems of active surplus and frequency deviation;
in order 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 requirement of the sending-end power grid;
for a traditional power system, the power grid active control requirement corresponding to a specific power transmission channel fault can be solved only based on the frequency offset of the power system, however, for a transmitting-end power grid containing large-scale new energy power generation, the new energy off-grid condition when an extra-high voltage direct-current power transmission channel fault occurs needs to be considered; therefore, the active control quantity P of the sending-end power grid is determined according to the following formulac：
In the above formula,. DELTA.f isFrequency deviation value, mu, of the transmitting-end grid0For the active-frequency sensitivity of the transmitting network, pkThe method is used for outputting power, lambda, of the kth new energy power station in the fault front-end power grid of the extra-high voltage direct-current transmission channelkThe method comprises the steps that the off-line proportion of a power generation unit in the kth new energy power station in a sending end power grid caused by the fault of an extra-high voltage direct current transmission channel is shown, k belongs to (1-L), and L is the total number of the new energy power stations in the sending end power grid;
in the best embodiment of the invention, the condition that the power generation unit is disconnected due to the fault of the extra-high voltage direct current transmission channel of the new energy power station in the power transmission end grid is considered, the active control requirement of the power transmission end grid can be obtained more accurately, and unnecessary active control is avoided.
The frequency deviation value delta f of the sending-end power grid is determined according to the following formula:
Δf＝fmax-fy
in the above formula, fmaxF is obtained by simulating the maximum value of the frequency of the transmission end power grid which can be reached without taking control measures after the fault of the extra-high voltage direct current transmission channelySending a frequency value of a power grid at a sending end when the frequency value reaches a threshold of a high-frequency generator tripping machine;
determining the active-frequency sensitivity mu of a transmitting-end power grid according to the following formula0：
In the above formula,. DELTA.f*For the value of the frequency change, Δ P, of the transmitting-end network*The active change value is the active change value corresponding to the frequency change value of the power grid at the sending end.
In the best embodiment of the invention, the new energy power station in the sending-end power grid is provided with the monitoring control system, and the grid-connected operation quantity of the new energy power station units, the off-grid quantity of the new energy power station due to faults, the output change information of the new energy power station and the like can be acquired by the monitoring control system.
Specifically, the step 102 includes:
step 102-1: setting i to be 1, and sequencing the appointed extra-high voltage direct-current transmission channels according to the sequence of active/frequency sensitivity from large to small;
step 102-2: if the ith in the sequence specifies the adjustable margin p of the extra-high voltage direct-current transmission channeli' less than PcRegulating and controlling the transmission capacity of the ith specified extra-high voltage direct-current transmission channel to be pi'+Pi(ii) a Otherwise, regulating and controlling the transmission capacity of the ith appointed extra-high voltage direct current transmission channel to be Pc+Pi；
Step 102-3: update P byc，
Step 102-4: if PcNot equal to 0 and i not equal to SnIf so, changing i to i +1, and returning to the step 2; if PcNot equal to 0 and i ═ SnThen, the surplus P of the active control quantity of the power grid at the transmitting end is subjected to active regulation and control on the appointed extra-high voltage direct current transmission channelc *＝Pc(ii) a Otherwise, the surplus P of the active control quantity of the power grid at the transmitting end is controlled after the active control is carried out on the appointed extra-high voltage direct current transmission channelc *＝0；
Wherein, PcIs the active control quantity of a transmitting end power grid, i belongs to (1-S)n)，SnTo specify the total number of extra-high voltage DC transmission channels, PiThe transmission capacity mu of the ith appointed extra-high voltage direct current transmission channel in the sequence before the extra-high voltage direct current transmission channel failsiSpecifying the active/frequency sensitivity, mu, of the ith designated extra-high voltage DC transmission channel in the sequence0The active/frequency sensitivity of the transmitting end grid.
In the best embodiment of the invention, surplus power transmission capacity of the specified extra-high voltage direct-current power transmission channel is utilized, on the premise of meeting the operation stability of the specified extra-high voltage direct-current power transmission channel, the power transmission power of the power transmission channel is rapidly increased, the active control requirement of a transmitting-end power grid is reduced, the power cutting amount of the transmitting-end power grid is reduced, the power requirement of a receiving-end power grid can be ensured, and the function of supporting the frequency modulation of a system is achieved.
In the best embodiment of the invention, the frequency variation after the system active disturbance is related to the active disturbance quantity, the extra-high voltage direct current transmission system is adopted to assist the sending end power grid to solve the high frequency problem, the transmission capacity of a specified extra-high voltage direct current transmission channel needs to be increased (equivalent to reducing the equivalent active disturbance quantity) so as to reduce the active surplus of the sending end power grid and balance the power generation and the load of the sending end power grid;
however, while considering the frequency safety of the transmission end power grid, the transient voltage safety and the transient stability of the transmission end power grid should be considered, and the transmission capacity of the specified extra-high voltage direct-current transmission channel should not exceed the transmission upper limit;
meanwhile, frequent regulation and control of the extra-high voltage direct-current transmission channel can also influence the operation of the extra-high voltage direct-current transmission system and the service life of equipment, and the minimum regulation and control quantity of the extra-high voltage direct-current transmission system should be ensured as far as possible;
the same active power transmission capacity is adjusted, and the response effect of the system frequency is better for the specified extra-high voltage direct current transmission channel with high active-frequency sensitivity than the specified extra-high voltage direct current transmission channel with high active-frequency sensitivity;
therefore, the regulation priority order of the appointed extra-high voltage direct-current transmission channel is set in the order of the active-frequency sensitivity from large to small, and the transmission capacity of the appointed extra-high voltage direct-current transmission channel is sequentially improved by adopting a method of multi-appointed extra-high voltage direct-current transmission channel cooperative regulation;
in the regulation process, the following constraint conditions are required to be met:
ft,max≤f1m
Vmin≤Vj≤Vmax
t,max≤1m
PDC，i≤PDC，1m
in the above formula, ft,maxFor the transient maximum frequency, f, of the transmitting-end network1mThe maximum frequency upper limit allowed by the sending-end power grid is the action threshold value V of the first circle of the high-frequency generator tripping of the systemjFor the voltage, V, of node j in the transmitting networkmaxFor the upper limit value, V, of the node voltage in the transmitting-end networkminIs the lower limit value of the node voltage in the power grid at the sending end,1mis the threshold value of the angle of attack difference in the power grid of the sending end,t,maxfor maximum angle of attack difference, P, in the transmitting-end gridDC，1mUpper limit value of transmission capacity, P, for extra-high voltage DC transmission channelDC，iAnd the transmission capacity of the ith appointed extra-high voltage direct-current transmission channel is determined.
Further, the muiThe obtaining process of (1), comprising:
setting Q groups of transmission capacity values of an ith appointed extra-high voltage direct-current transmission channel in the extra-high voltage direct-current transmission system simulation environment, and recording receiving end power grid frequency values in the extra-high voltage direct-current transmission system simulation environment respectively corresponding to the Q groups of transmission capacity values;
fitting a function relation with the transmission capacity value as an independent variable and the receiving end power grid frequency value as a dependent variable based on the Q groups of transmission capacity values and the receiving end power grid frequency values in the ultra-high voltage direct current transmission system simulation environment respectively corresponding to the Q groups of transmission capacity values;
obtaining the mu by calculating the independent variable deviation in the function relationi；
Wherein Q is the total group number of the preset experimental data.
Specifically, the step 103 includes:
step 103-1: carrying out active regulation and control on a first type of new energy power station in a sending-end power grid according to the sequence of predicting the rising value of the output amplitude from large to small in a preset time period, and acquiring the residual quantity P of the active control quantity of the sending-end power grid after the active regulation and control is carried out on the first type of new energy power station in the sending-end power gridc T；
In the best embodiment of the invention, because the output of the new energy power station has fluctuation, when the extra-high voltage direct current transmission channel fails, the output of some new energy power stations is in an ascending stage, the output of some new energy power stations is in a descending stage, and the output of other new energy power stations is relatively stable.
If the new energy power station to be cut is not selected reasonably, the output of the new energy power station which is not cut is in a rising stage, and the power surplus of the power grid at the sending end is caused again.
In order to solve the problem, the output change trend of each related new energy power station is determined according to the real-time output data of the new energy power station and the ultra-short-term predicted output condition;
and preferably, a new energy power station with the output force rising within phi time after the fault is selected to be switched off, so that the risk of power surplus of the power grid at the sending end is reduced.
Step 103-2: when P is presentc TIf not, performing active regulation and control on the second type new energy power station in the sending-end power grid, and acquiring the surplus P of the active control quantity of the sending-end power grid after performing active regulation and control on the second type new energy power station in the sending-end power gridc Z；
In the best embodiment of the invention, the new energy power station which does not output power to rise within phi duration after the fault is cut off in proportion.
Step 103-3: when P is presentc ZAnd if not, regulating and controlling the output of the conventional unit in the power grid of the sending end by adopting a high-frequency generator tripping strategy of the conventional unit until the residual quantity of the active control quantity of the power grid of the sending end is 0.
Still further, the step 103-1 includes:
step 103-1-1: sequencing the first type of new energy power stations in the power grid at the sending end according to the sequence of predicting the rising value of the output amplitude from large to small in a preset time period;
step 103-1-2: if m is present, m satisfies
The output of the 1 st to the m-1 st new energy power stations in the sequence is controlled to be 0, and the output of the m first new energy power station in the sequence is controlled to be
Otherwise, the output of each first-class new energy power station in the regulation and control sequence is 0;
step 103-1-3: obtaining the surplus P of the active control quantity of the sending-end power grid after the first type of new energy power station in the sending-end power grid is subjected to active regulation and control according to the following formulac T；
Wherein, Ps,dThe predicted capacity of the d-th new energy power station of the first type in the sequence is m belongs to (1-S)d)，SdThe total number of the first type of new energy power stations in the transmission-end power grid.
In the best embodiment of the invention, in order to reduce the machine switching amount of the new energy power station as much as possible, the regulation and control sequence of the first type of new energy power station should be set according to the output rise amplitude within the phi time length after the fault.
Further, the step 103-2 includes:
step 103-2-1: if it is
The output of the second type new energy power station in the sending end power grid is regulated to be 0, otherwise, the output of the h second type new energy power station in the sending end power grid is regulated to be 0
Step 103-2-2: obtaining the surplus P of the active control quantity of the sending-end power grid after the second type of new energy power station in the sending-end power grid is subjected to active regulation and control according to the following formulac Z；
Wherein, Pw,hThe predicted output of the h second type new energy power station in the sending end power grid is h belongs to (1-S)h)，ShThe total number of the h second type new energy power stations in the sending end power grid.
In the preferred embodiment of the present invention, to ensure fairness, the power generation of the second type new energy power station should be cut off proportionally.
The invention provides an active regulation and control system for an extra-high voltage direct current transmission channel during fault, as shown in fig. 2, the system comprises:
the determining module is used for determining the active control quantity of the power grid of the transmitting end according to the frequency deviation value of the power grid of the transmitting end;
the first regulation and control module is used for carrying out active regulation and control on the specified extra-high voltage direct-current transmission channel according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid and the sequence of active/frequency sensitivity from large to small;
the designated extra-high voltage direct-current transmission channel is a non-fault extra-high voltage direct-current transmission channel which is connected with the same receiving-end power grid and the same transmitting-end power grid as the fault extra-high voltage direct-current transmission channel.
Specifically, the system further includes: a second regulatory module;
the second regulation and control module is used for continuing to carry out active regulation and control on a new energy power station and/or a conventional unit in the power transmission end power grid according to a preset regulation and control priority when the active control quantity of the power transmission end power grid still has surplus;
the preset regulation and control priorities of a first type of new energy power station in a delivery-end power grid, a second type of new energy power station in the delivery-end power grid and a conventional unit in the delivery-end power grid are sequentially reduced;
the first type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is in an ascending stage in a preset time period in the sending-end power grid;
a second type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is not in a rising stage within a preset time period in the sending-end power grid;
the starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, and phi is a positive number.
Specifically, the determining module is configured to:
determining active control quantity P of sending end power grid according to the following formulac：
In the above formula, Δ f is the sending terminalFrequency deviation value of net, mu0For the active-frequency sensitivity of the transmitting network, pkThe method is used for outputting power, lambda, of the kth new energy power station in the fault front-end power grid of the extra-high voltage direct-current transmission channelkThe method comprises the steps that the off-line proportion of a power generation unit in the kth new energy power station in a sending end power grid caused by the fault of an extra-high voltage direct current transmission channel is shown, k belongs to (1-L), and L is the total number of the new energy power stations in the sending end power grid;
the frequency deviation value delta f of the sending-end power grid is determined according to the following formula:
Δf＝fmax-fy
in the above formula, fmaxF is the maximum value that the frequency of a sending end power grid can reach after the fault of the extra-high voltage direct current transmission channel without taking control measuresySending a frequency value of a power grid at a sending end when the frequency value reaches a threshold of a high-frequency generator tripping machine;
determining the active-frequency sensitivity mu of a transmitting-end power grid according to the following formula0：
In the above formula,. DELTA.f*For the value of the frequency change, Δ P, of the transmitting-end network*The active change value is the active change value corresponding to the frequency change value of the power grid at the sending end.
Specifically, the first regulatory module includes:
the sorting unit is used for enabling i to be 1 and sorting the appointed extra-high voltage direct-current transmission channels according to the sequence of the active/frequency sensitivity from large to small;
a first regulating and controlling unit for regulating the margin p of the ith appointed extra-high voltage direct current transmission channel in the sequencei' less than PcRegulating and controlling the transmission capacity of the ith specified extra-high voltage direct-current transmission channel to be pi'+Pi(ii) a Otherwise, regulating and controlling the transmission capacity of the ith appointed extra-high voltage direct current transmission channel to be Pc+Pi；
An updating unit for updating P according to the following formulac，
A command unit for if PcNot equal to 0 and i not equal to SnIf so, changing i to i +1, and returning to the step 2; if PcNot equal to 0 and i ═ SnThen, the surplus P of the active control quantity of the power grid at the transmitting end is subjected to active regulation and control on the appointed extra-high voltage direct current transmission channelc *＝Pc(ii) a Otherwise, the surplus P of the active control quantity of the power grid at the transmitting end is controlled after the active control is carried out on the appointed extra-high voltage direct current transmission channelc *＝0；
Wherein, PcIs the active control quantity of a transmitting end power grid, i belongs to (1-S)n)，SnTo specify the total number of extra-high voltage DC transmission channels, PiThe transmission capacity mu of the ith appointed extra-high voltage direct current transmission channel in the sequence before the extra-high voltage direct current transmission channel failsiSpecifying the active/frequency sensitivity, mu, of the ith designated extra-high voltage DC transmission channel in the sequence0The active/frequency sensitivity of the transmitting end grid.
Further, the muiThe obtaining process of (1), comprising:
setting Q groups of transmission capacity values of an ith appointed extra-high voltage direct-current transmission channel in the extra-high voltage direct-current transmission system simulation environment, and recording receiving end power grid frequency values in the extra-high voltage direct-current transmission system simulation environment respectively corresponding to the Q groups of transmission capacity values;
fitting a function relation with the transmission capacity value as an independent variable and the receiving end power grid frequency value as a dependent variable based on the Q groups of transmission capacity values and the receiving end power grid frequency values in the ultra-high voltage direct current transmission system simulation environment respectively corresponding to the Q groups of transmission capacity values;
obtaining the mu by calculating the independent variable deviation in the function relationi；
Wherein Q is the total group number of the preset experimental data.
Further, the second regulatory unit comprises:
the second regulation and control unit is used for carrying out active regulation and control on the first type of new energy power station in the power grid at the transmitting end according to the sequence that the rising value of the output amplitude is predicted to be from large to small in the preset time periodAnd obtaining the surplus P of the active control quantity of the transmission-end power grid after the first type of new energy power station in the transmission-end power grid is subjected to active regulation and controlc T；
A third regulatory unit for Pc TIf not, performing active regulation and control on the second type new energy power station in the sending-end power grid, and acquiring the surplus P of the active control quantity of the sending-end power grid after performing active regulation and control on the second type new energy power station in the sending-end power gridc Z；
A fourth regulatory unit for Pc ZAnd if not, regulating and controlling the output of the conventional unit in the power grid of the sending end by adopting a high-frequency generator tripping strategy of the conventional unit until the residual quantity of the active control quantity of the power grid of the sending end is 0.
Further, the second regulatory unit comprises:
the sequencing subunit is used for sequencing the first type of new energy power stations in the transmission-end power grid according to the sequence that the rising value of the output force amplitude is predicted to be from large to small in a preset time period;
a first regulatory subunit for m, if present, being satisfied
The output of the 1 st to the m-1 st new energy power stations in the sequence is controlled to be 0, and the output of the m first new energy power station in the sequence is controlled to be
Otherwise, the output of each first-class new energy power station in the regulation and control sequence is 0;
a first obtaining subunit, configured to obtain, according to the following formula, a remaining amount P of an active control amount of a transmission-end power grid after active regulation and control is performed on a first type of new energy power station in the transmission-end power gridc T；
Wherein, Ps,dFor prediction of the d-th new energy power station of the first kind in the sequenceForce, m ∈ (1 to S)d)，SdThe total number of the first type of new energy power stations in the transmission-end power grid.
Further, the third regulatory unit comprises:
a second regulatory subunit of
The output of the second type new energy power station in the sending end power grid is regulated to be 0, otherwise, the output of the h second type new energy power station in the sending end power grid is regulated to be 0
A second obtaining subunit, configured to obtain, according to the following formula, a remaining amount P of an active control amount of the transmission-end power grid after the active control is performed on the second type of new energy power station in the transmission-end power gridc Z；
Wherein, Pw,hThe predicted output of the h second type new energy power station in the sending end power grid is h belongs to (1-S)h)，ShThe total number of the h second type new energy power stations in the sending end power grid.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (10)
1. The active regulation and control method for the fault of the extra-high voltage direct current transmission channel is characterized by comprising the following steps:
determining the active control quantity of the power grid of the transmitting end according to the frequency deviation value of the power grid of the transmitting end;
according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid, performing active regulation and control on the specified extra-high voltage direct-current transmission channel according to the sequence of active/frequency sensitivity from large to small;
the designated extra-high voltage direct-current transmission channel is a non-fault extra-high voltage direct-current transmission channel which is connected with the same receiving-end power grid and the same transmitting-end power grid as the fault extra-high voltage direct-current transmission channel.
2. The method according to claim 1, wherein after performing active regulation and control on the specified extra-high voltage direct-current transmission channel according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of the transmission-end power grid and the sequence of the active/frequency sensitivity from large to small, the method further comprises:
when the active control quantity of the power grid at the transmitting end still has surplus, continuously carrying out active regulation and control on a new energy power station and/or a conventional unit in the power grid at the transmitting end according to a preset regulation and control priority;
the preset regulation and control priorities of a first type of new energy power station in a delivery-end power grid, a second type of new energy power station in the delivery-end power grid and a conventional unit in the delivery-end power grid are sequentially reduced;
the first type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is in an ascending stage in a preset time period in the sending-end power grid;
a second type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is not in a rising stage within a preset time period in the sending-end power grid;
the starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, and phi is a positive number.
3. The method of claim 1, wherein determining the active control quantity of the sending-end power grid according to the frequency deviation value of the sending-end power grid comprises:
determining the active power of a transmitting end power grid according to the following formulaControl quantity Pc：
In the above formula, Δ f is the frequency deviation value, μ, of the transmitting-end power grid0For the active-frequency sensitivity of the transmitting network, pkThe method is used for outputting power, lambda, of the kth new energy power station in the fault front-end power grid of the extra-high voltage direct-current transmission channelkThe method comprises the steps that the off-line proportion of a power generation unit in the kth new energy power station in a sending end power grid caused by the fault of an extra-high voltage direct current transmission channel is shown, k belongs to (1-L), and L is the total number of the new energy power stations in the sending end power grid;
the frequency deviation value delta f of the sending-end power grid is determined according to the following formula:
Δf＝fmax-fy
in the above formula, fmaxF is the maximum value that the frequency of a sending end power grid can reach after the fault of the extra-high voltage direct current transmission channel without taking control measuresySending a frequency value of a power grid at a sending end when the frequency value reaches a threshold of a high-frequency generator tripping machine;
determining the active-frequency sensitivity mu of a transmitting-end power grid according to the following formula0：
In the above formula,. DELTA.f*For the value of the frequency change, Δ P, of the transmitting-end network*The active change value is the active change value corresponding to the frequency change value of the power grid at the sending end.
4. The method according to claim 1, wherein the active regulation and control of the specified extra-high voltage direct-current transmission channel according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of the transmission-end power grid and the sequence of the active/frequency sensitivity from large to small comprises the following steps:
step 1: setting i to be 1, and sequencing the appointed extra-high voltage direct-current transmission channels according to the sequence of active/frequency sensitivity from large to small;
step 2: if the ith appointed extra-high voltage direct-current transmission channel in the sequence has adjustable margin p'iLess than PcRegulating and controlling the transmission capacity of the ith appointed extra-high voltage direct current transmission channel to be p'i+Pi(ii) a Otherwise, regulating and controlling the transmission capacity of the ith appointed extra-high voltage direct current transmission channel to be Pc+Pi；
And step 3: update P byc，
And 4, step 4: if PcNot equal to 0 and i not equal to SnIf so, changing i to i +1, and returning to the step 2; if PcNot equal to 0 and i ═ SnThen, the surplus P of the active control quantity of the power grid at the transmitting end is subjected to active regulation and control on the appointed extra-high voltage direct current transmission channelc *＝Pc(ii) a Otherwise, the surplus P of the active control quantity of the power grid at the transmitting end is controlled after the active control is carried out on the appointed extra-high voltage direct current transmission channelc *＝0；
Wherein, PcIs the active control quantity of a transmitting end power grid, i belongs to (1-S)n)，SnTo specify the total number of extra-high voltage DC transmission channels, PiThe transmission capacity mu of the ith appointed extra-high voltage direct current transmission channel in the sequence before the extra-high voltage direct current transmission channel failsiSpecifying the active/frequency sensitivity, mu, of the ith designated extra-high voltage DC transmission channel in the sequence0The active/frequency sensitivity of the transmitting end grid.
5. The method of claim 4, wherein said μiThe obtaining process of (1), comprising:
setting Q groups of transmission capacity values of an ith appointed extra-high voltage direct-current transmission channel in the extra-high voltage direct-current transmission system simulation environment, and recording receiving end power grid frequency values in the extra-high voltage direct-current transmission system simulation environment respectively corresponding to the Q groups of transmission capacity values;
fitting a function relation with the transmission capacity value as an independent variable and the receiving end power grid frequency value as a dependent variable based on the Q groups of transmission capacity values and the receiving end power grid frequency values in the ultra-high voltage direct current transmission system simulation environment respectively corresponding to the Q groups of transmission capacity values;
obtaining the mu by calculating the independent variable deviation in the function relationi；
Wherein Q is the total group number of the preset experimental data.
6. The method according to claim 2, wherein when the active control quantity of the transmission-end power grid remains after active regulation and control is performed on the specified extra-high voltage direct current transmission channel, the active regulation and control on the new energy power station and/or the conventional unit in the transmission-end power grid is continued according to a preset regulation and control priority, and the method comprises the following steps:
step A: carrying out active regulation and control on a first type of new energy power station in a sending-end power grid according to the sequence of predicting the rising value of the output amplitude from large to small in a preset time period, and acquiring the residual quantity P of the active control quantity of the sending-end power grid after the active regulation and control is carried out on the first type of new energy power station in the sending-end power gridc T；
And B: when P is presentc TIf not, performing active regulation and control on the second type new energy power station in the sending-end power grid, and acquiring the surplus P of the active control quantity of the sending-end power grid after performing active regulation and control on the second type new energy power station in the sending-end power gridc Z；
And C: when P is presentc ZAnd if not, regulating and controlling the output of the conventional unit in the power grid of the sending end by adopting a high-frequency generator tripping strategy of the conventional unit until the residual quantity of the active control quantity of the power grid of the sending end is 0.
7. The method of claim 6, wherein step a, comprises:
step A-1: sequencing the first type of new energy power stations in the power grid at the sending end according to the sequence of predicting the rising value of the output amplitude from large to small in a preset time period;
step A-2: if m is present, m satisfies
The output of the 1 st to the m-1 st new energy power stations in the sequence is controlled to be 0, and the output of the m first new energy power station in the sequence is controlled to be
Otherwise, the output of each first-class new energy power station in the regulation and control sequence is 0;
step A-3: obtaining the surplus P of the active control quantity of the sending-end power grid after the first type of new energy power station in the sending-end power grid is subjected to active regulation and control according to the following formulac T；
Wherein, Ps,dThe predicted capacity of the d-th new energy power station of the first type in the sequence is m belongs to (1-S)d)，SdThe total number of the first type of new energy power stations in the transmission-end power grid.
8. The method of claim 6, wherein the method is as set forth in claim 6
Step B-1: if it is
The output of the second type new energy power station in the sending end power grid is regulated to be 0, otherwise, the output of the h second type new energy power station in the sending end power grid is regulated to be 0
Step 3-2: obtaining the surplus P of the active control quantity of the sending-end power grid after the second type of new energy power station in the sending-end power grid is subjected to active regulation and control according to the following formulac Z；
Wherein, Pw,hThe predicted output of the h second type new energy power station in the sending end power grid is h belongs to (1-S)h)，ShThe total number of the h second type new energy power stations in the sending end power grid.
9. An active regulation and control system for when extra-high voltage direct current transmission channel is out of order, its characterized in that, the system includes:
the determining module is used for determining the active control quantity of the power grid of the transmitting end according to the frequency deviation value of the power grid of the transmitting end;
the first regulation and control module is used for carrying out active regulation and control on the specified extra-high voltage direct-current transmission channel according to the adjustable margin of the specified extra-high voltage direct-current transmission channel and the active control quantity of a transmission end power grid and the sequence of active/frequency sensitivity from large to small;
the designated extra-high voltage direct-current transmission channel is a non-fault extra-high voltage direct-current transmission channel which is connected with the same receiving-end power grid and the same transmitting-end power grid as the fault extra-high voltage direct-current transmission channel.
10. The system of claim 9, wherein the system further comprises:
the second regulation and control module is used for continuing to carry out active regulation and control on a new energy power station and/or a conventional unit in the transmission end power grid according to a preset regulation and control priority when the active control quantity of the transmission end power grid still has surplus after the active regulation and control is carried out on the appointed extra-high voltage direct-current transmission channel;
the preset regulation and control priorities of a first type of new energy power station in a delivery-end power grid, a second type of new energy power station in the delivery-end power grid and a conventional unit in the delivery-end power grid are sequentially reduced;
the first type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is in an ascending stage in a preset time period in the sending-end power grid;
a second type of new energy power station in the sending-end power grid is a new energy power station which predicts that the output is not in a rising stage within a preset time period in the sending-end power grid;
the starting time of the preset time interval is the fault time of the extra-high voltage direct current transmission channel, the duration of the preset time interval is phi, and phi is a positive number.
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| CN116630090A (en) * | 2023-07-14 | 2023-08-22 | 中国电力科学研究院有限公司 | Method and device for determining minimum starting-up capacity of thermal power generating unit based on voltage stabilization |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116630090A (en) * | 2023-07-14 | 2023-08-22 | 中国电力科学研究院有限公司 | Method and device for determining minimum starting-up capacity of thermal power generating unit based on voltage stabilization |
| CN116630090B (en) * | 2023-07-14 | 2023-09-26 | 中国电力科学研究院有限公司 | Method and device for determining minimum starting-up capacity of thermal power generating unit based on voltage stabilization |
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