CN108565872B - Method and device with reactive compensation rapid switching function - Google Patents
Method and device with reactive compensation rapid switching function 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
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
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Abstract
The invention discloses a method with a reactive compensation rapid switching function, which mainly comprises the steps of monitoring the bus voltage of a controllable capacitor in real time by using a safety automatic device, and judging whether a system has a short-circuit fault condition according to the actual voltage value of the monitored bus; when the device judges the low-voltage round action of the main transformer, all reactors on the same bus or a parallel bus with the main transformer are cut off, and then a part of capacitors which can be put into the main transformer are selected; after the capacitors are put into use, if the voltage is higher after the system is recovered, the capacitors in 1 group are withdrawn after a certain time delay, if the overvoltage starting is still not returned, the capacitors in 1 group are withdrawn at regular intervals until all the main transformers on the main transformer hanging buses or the parallel buses are returned after the overvoltage starting or the put capacitors are completely cut off. The method can enhance the dynamic reactive power supporting capability of the receiving-end power grid, improve the voltage stability of the power grid and meet the requirement of quickly putting into the capacitor under the condition of protection or switch failure.
Description
Technical Field
The invention relates to the technical field of safety and stability control of an electric power system, in particular to a method and a device with a reactive compensation rapid switching function.
Background
In the southern power grid system, a large number of reactive devices are arranged at each voltage level site, and operation practice shows that part of the capacitors are in a standby state even under a large load condition. If an automatic device can be adopted to automatically put in a standby capacitor when the system voltage is reduced, the voltage stability of the system can be improved at a lower cost; in the aspect of control strategy, if the capacitor can be put into use under the condition that the system has fault protection or the switch fails to operate and does not operate under the condition that the protection is correctly cut off, the probability of the operation of the capacitor can be reduced, and the service life of the capacitor can be prolonged; in the input time, the smaller the action time delay of the rapid input capacitor is, the more capacitors are probably input, and the better the voltage recovery of the fault station is. The AVC and VQC adopted at present can also control the switching of the capacitor, the action time delay is about 30s generally, but the requirement of rapidly switching the capacitor cannot be met in the time scale.
Disclosure of Invention
The invention aims to solve the technical problems in the prior art at least to a certain extent, and provides a method and a device with a reactive compensation rapid switching function, so as to further enhance the dynamic reactive support capability of a receiving-end power grid, improve the voltage stability of the power grid and meet the requirement of rapidly switching into a capacitor under the condition of protection or switch failure.
In order to achieve the purpose of the present invention, an embodiment of the present invention provides a method with a reactive compensation fast switching function, which specifically adopts the following technical scheme:
the method comprises the following steps:
(1) the safety automatic device monitors the bus voltage of the controllable capacitor in real time and judges whether the system has short-circuit fault according to the actual voltage value of the monitored bus;
(2) when the safety automatic device judges the low-voltage round action of the main transformer, a reactor on the same bus or a parallel bus with the main transformer is cut off, and then a part of capacitors which can be put into the main transformer are selected;
(3) after capacitors are put into the system, if the voltage is higher after the system is recovered, 1 group of capacitors are withdrawn after time delay t, if overvoltage starting is not returned, one group of capacitors are withdrawn at time interval t until all main transformers on a bus where the main transformers are located or a parallel bus are returned after overvoltage starting or all the put capacitors are cut off, wherein t is a capacitor withdrawal delay fixed value.
Optionally, in the step (1), a plurality of main transformers are included, and the bus voltage of the controllable capacitor is selected from the high-voltage side voltages of the plurality of main transformers.
Optionally, the step (2) comprises:
(2.1) judging the low-voltage turn action of the main transformer;
when the main transformer detects that the voltage is lower than a certain action turn fixed value of the low voltage of the safety automatic device, delaying the time for m, wherein the low voltage corresponds to the action turn;
wherein m is a low-voltage action turn delay fixed value corresponding to the safety automatic device;
(2.2) acquiring the number of capacitor sets required to be put into the main transformer low-voltage action turns;
(2.3) if the number of the capacitor banks needing to be put into is nonzero, cutting off all reactors on the same bus or a parallel bus with the main transformer;
(2.4) selecting and putting the capacitors with the same number of groups according to the priority sequence of the capacitors under the main transformer;
(2.5) re-prioritizing the capacitors, prioritizing the capacitors that have been placed to the end, and storing in a memory location.
Optionally, the step (2.1) further comprises: each main transformer is provided with a first low-voltage action round, a second low-voltage action round and a third low-voltage action round, and the first low-voltage action round, the second low-voltage action round and the third low-voltage action round are independent rounds and adopt positive sequence voltage to judge; the first low-voltage action round and the second low-voltage action round have the low-voltage round action judging function only under the condition that a system has a short-circuit fault, and the third low-voltage wheel is not limited by whether the short-circuit fault occurs or not.
Optionally, the step (2.4) specifically includes:
(2.41) acquiring the priority sequence of the main transformer capacitors; each group of capacitors under the main transformer is endowed with an initial priority fixed value, the initial priority sequence of each group of capacitors can be determined through fixed value setting, the priority sequence can be modified into the initial priority sequence every time the fixed value is manually modified, and the initial priority sequence is stored in a storage unit; after the capacitors are put into the device for each time of operation, the capacitor banks are subjected to priority ranking again and stored in a storage unit; the safety automatic device obtains capacitor priority sequencing under each main transformer through reading and storing the capacitor priority sequencing in a storage unit;
(2.42) charging a capacitor in accordance with capacitor charging conditions including:
when the capacitor group is overhauled, the corresponding allowable switching pressing plate is withdrawn, and the capacitor group cannot be switched;
judging whether the group of capacitors are in a hot standby state or not under the condition that the capacitors are in the hot standby state, and when the corresponding capacitor switch positions are time-sharing, the capacitors are in the hot standby state and can be put into use;
the capacitor has no relevant blocking signal condition, when the blocking signal exists in the capacitor, the selective switching function of the group of capacitors is blocked:
under the condition that the capacitor is discharged completely, the capacitor can be put into the furnace again after n time after being cut off; n is the capacitor discharge time set by the safety automatic device;
the whole group of time conditions of the action, the group of capacitors is not put into the action in the whole group of time, and the capacitors can be put into the action; after the device is started, if the fault disappears, the device is judged to be a whole group of reset after 5 s;
and setting the initial priority of the capacitor to be non-zero, and putting the capacitor into use when the initial priority of the capacitor is set to be non-zero.
Optionally, the step (3) specifically includes the following steps:
(3.1) circulating overvoltage actions of any main transformer in the selection range, namely generating an overvoltage strategy of the selection range, wherein the overvoltage strategy is that the capacitors are switched for the first time without delay, and then all the capacitors are cut off after k time delay; where k is the overvoltage-switching capacitance time interval.
(3.2) in the determined circular selection and cutting range, under the condition that the priority of the overvoltage cutting capacitor main transformer is close to that of the front main transformer, a group of capacitors with the priority of the cuttable capacitor priority being close to that of the front main transformer is cut off;
(3.3) reordering the priority of the overvoltage cutting capacitor main transformer, arranging the priority of the main transformer with the capacitor cut off in action at the end, and storing the priority in a storage unit;
(3.4) if the circulating selection and switching range has overvoltage starting and does not return to the main transformer and the capacitors thrown into the safety automatic device are not completely cut off, turning to the step (3.5), otherwise, turning to the step (3.6);
(3.5) judging whether k time delay is passed, if so, turning to the step 3-2, and if not, turning to the step 3-4;
and (3.6) the logic of the capacitor is cut off in the cycle range.
Optionally, the step (3.1) specifically includes:
main transformer overvoltage judgment logic: if the main transformer low-voltage input capacitor is too much, the main transformer overvoltage is higher than the overvoltage action fixed value of the safety automatic device, and the main transformer overvoltage acts after g time delay; each main transformer is provided with 1 overvoltage action turn, and overvoltage is judged by adopting positive sequence voltage; only under the condition that the low voltage of the main transformer is put into the capacitor, the overvoltage judgment function of the main transformer is opened; wherein g is an overvoltage action delay fixed value corresponding to the safety automatic device;
the circular selection range comprises:
circular selection range 1: under the condition that buses run in parallel, all running main transformers;
circular selection range 2: under the condition that the buses are operated in rows, the operation main transformer is hung on the I-section bus;
the circular selection range 3: and under the condition that the buses are operated in rows, the operation main transformer is hung on the section II buses.
Optionally, the step (3.2) specifically includes:
1) and (3) sequencing the priorities of main transformer of the overvoltage cutting capacitor:
the safety automatic device performs priority sequencing on the main transformers in the determined cycle selection and switching range according to the main transformer priority fixed value of the overvoltage switching capacitor, the sequencing with the smaller fixed value is forward, the fixed value is set to be zero and does not participate in the priority sequencing, the priority sequencing of the overvoltage switching capacitor main transformers is modified into initial priority sequencing by manually modifying the fixed value every time, and the initial priority sequencing is stored in a storage unit; after the capacitors are switched every time, the priority of the main transformer of the overvoltage switching capacitors is reordered, and the priority of the main transformer of the current switching capacitor is arranged at the end and stored in a storage unit; the safety automatic device obtains the priority sequence of the overvoltage-cutting capacitor main transformer by reading the storage unit.
2) The priority sequence of the capacitors can be switched under each main transformer:
and performing priority ranking on the cut capacitors under each main transformer in the determined cyclic selection and cutting range, wherein the capacitor which is firstly put in is in front of the priority ranking, and the cut capacitor does not participate in the priority ranking.
Compared with the prior art, the method and the device have the following beneficial effects:
the method and the device provided by the embodiment of the invention can quickly put part of the capacitors into the system under the conditions of system failure and protection or switch failure, and can cut off part of the capacitors if the voltage is higher after the system is recovered, so that the voltage stability of the system is improved at a lower cost. The invention can effectively reduce the load shedding amount on the premise of keeping the transient voltage of the system stable by matching with the low-voltage load shedding device, and has positive effect on maintaining the operation stability and the economical efficiency of the power system.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a method with a reactive compensation fast switching function according to an embodiment of the present invention;
FIG. 2 is a flowchart of the operation of the main transformer low-voltage operation switching capacitor according to the embodiment of the present invention;
fig. 3 is a flowchart of a main transformer overvoltage crowbar capacitor working process according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to explain the technical solution of the present invention, the following description is made by referring to the specific embodiments and the accompanying drawings.
The embodiment of the invention provides a method with a reactive compensation rapid switching function, which is applied to the safety and stability control of a power system, realizes that partial capacitors are rapidly put into the system under the condition of fault protection or switch failure of the system, and cuts off partial capacitors under the condition of high system recovery voltage, so that the voltage stability of the system is improved at a lower cost, and provides the following specific technical scheme:
as shown in fig. 1, the method comprises the steps of:
(1) monitoring the bus voltage of the controllable capacitor in real time by using a safety automatic device, and judging whether the system has a short-circuit fault according to the actual voltage value of the monitored bus;
(2) when the safety automatic device judges the low-voltage round action of the main transformer, a reactor on the same bus or a parallel bus with the main transformer is cut off, and then a part of capacitors which can be put into the main transformer are selected;
(3) after capacitors are put into the system, if the voltage is higher after the system is recovered, 1 group of capacitors are withdrawn after time delay t, if overvoltage starting is not returned, one group of capacitors are withdrawn at time interval t until all main transformers on a bus where the main transformers are located or a parallel bus are returned after overvoltage starting or all the put capacitors are cut off, wherein t is a capacitor withdrawal delay fixed value.
The safety automatic device has a reactive compensation rapid switching function, and comprises a hardware part and a software part, wherein the hardware part comprises a main CPU (Central processing Unit) processing module, an analog quantity input module, an input quantity input module, an output quantity output module, a communication management module and the like, and the main CPU processing module is respectively communicated with the analog quantity input module, the input quantity input module, the output quantity output module and the communication management module through a dual CAN (controller area network) network (CAN 0 network and CAN1 network); the software part comprises the discrimination of system short circuit fault, the realization of the function of a main transformer low-voltage switching capacitor, the realization of the function of a main transformer overvoltage switching capacitor and the like.
The method provided by the embodiment of the invention realizes that partial capacitors are quickly put into the system under the condition of fault protection or switch failure, and partial capacitors are cut off under the condition of high system recovery voltage, so that the voltage stability of the system is improved at a lower cost.
In one embodiment, the controllable capacitor comprises a plurality of main transformers, and the bus voltage of the controllable capacitor selects the high-voltage side voltage of the plurality of main transformers. In this embodiment, the high-voltage side voltage of the transformer is selected according to the bus voltage monitored by the controllable capacitor under the condition of the system voltage stability. Meanwhile, the later-stage universality of the device is considered, 4 main transformers are connected, and the low-voltage side of each main transformer is designed according to 4 groups of capacitors and 2 groups of reactors. It should be noted that the above main transformers, capacitors, and reactors are only one example of the present invention.
The judgment of the short-circuit fault is carried out through the voltage change rate du/dt of a main transformer, the du/dt adopts phase-to-phase voltage (line voltage) to calculate, and when the absolute value | du/dt | > of any phase-to-phase voltage change rate (which must be a reduction change rate) in the three phase-to-phase voltage is larger than a 'voltage change rate fixed value' set by a safety automatic device, the device judges that the short-circuit fault occurs.
In an embodiment, as shown in fig. 2, a working flow chart of the main transformer low-voltage operation throw capacitor is shown, specifically, the step (2) includes:
(2.1) judging the low-voltage turn action of the main transformer;
when the main transformer detects that the voltage is lower than a certain action turn fixed value of the low voltage of the safety automatic device, delaying the time for m, wherein the low voltage corresponds to the action turn;
wherein m is a low-voltage action turn delay fixed value corresponding to the safety automatic device;
(2.2) acquiring the number of capacitor sets required to be put into the main transformer low-voltage action turns;
(2.3) if the number of the capacitor banks needing to be put into is nonzero, cutting off all reactors on the same bus or a parallel bus with the main transformer;
(2.4) selecting and putting the capacitors with the same number of groups according to the priority sequence of the capacitors under the main transformer;
(2.5) re-prioritizing the capacitors, prioritizing the capacitors that have been placed to the end, and storing in a memory location.
And (2.6) the logic of the main transformer low voltage corresponding to the turn of capacitor throwing is finished.
In one embodiment, the step (2.1) further comprises: each main transformer is provided with a first low-voltage action round, a second low-voltage action round and a third low-voltage action round, and the first low-voltage action round, the second low-voltage action round and the third low-voltage action round are independent rounds and adopt positive sequence voltage to judge; it should be noted that the low-voltage operation determination function is only opened when the system has a short-circuit fault in the first low-voltage operation round and the second low-voltage operation round, and the third low-voltage wheel is not limited by whether a short-circuit fault occurs.
Further, in the step (2.2), each main transformer is provided with 3 low-voltage operation turns, and the number of capacitor banks to be put into each low-voltage operation turn can be set. Taking 1# low-voltage-to-1-turn as an example, the number of capacitor banks required to be charged in 1# main transformer low-voltage-to-1-turn is a fixed value setting value of 'the number of capacitors charged in 1# low-voltage-to-1-turn'.
Further, in the step (2.3), when the hot standby parallel capacitor and the low-voltage reactor exist on the same bus at the same time, the capacitor and the reactor are never allowed to operate on the same bus (bus in split operation) or on the parallel bus at the same time during switching, otherwise, a resonance problem of an LC loop is generated, and equipment damage is caused in a serious case. Therefore, when the capacitor needs to be put into use, whether the running reactor exists on the main transformer hanging bus or the parallel bus is detected firstly, if so, the reactor is cut off preferentially, and the capacitor can be put into use only after all the reactors are cut off; the operation state judgment of the operation reactor under each main transformer is mainly realized by introducing a remote signaling position of a switch corresponding to the reactor, for example: if the remote communication quantity of the switch is the closing position, the running state of the reactor is judged.
In an embodiment, the step (2.4) specifically includes:
(2.41) acquiring the priority sequence of the main transformer capacitors; each group of capacitors under the main transformer is endowed with an initial priority fixed value, the initial priority sequence of each group of capacitors can be determined through fixed value setting, the priority sequence can be modified into the initial priority sequence every time the fixed value is manually modified, and the initial priority sequence is stored in a storage unit; after the capacitors are put into the device for each time of operation, the capacitor banks are subjected to priority ranking again and stored in a storage unit; the safety automatic device obtains capacitor priority sequencing under each main transformer through reading and storing the capacitor priority sequencing in a storage unit; in this embodiment, the storage unit is preferably, but not limited to, an Electrically Erasable Programmable Read Only Memory (EEPROM).
(2.42) charging a capacitor in accordance with capacitor charging conditions including:
when the capacitor group is overhauled, the corresponding allowable switching pressing plate is withdrawn, and the capacitor group cannot be switched;
the capacitor is in a hot standby state condition, whether the group of capacitors are in the hot standby state or not is judged by introducing a switch position signal (HWJ) of the capacitor, and when the corresponding capacitor switch position (HWJ) is time-sharing, the capacitor is in the hot standby state and can be switched on, otherwise, the capacitor cannot be switched on;
the capacitor has no relevant blocking signal condition, a blocking signal of the capacitor is introduced, and when the blocking signal exists in the capacitor, the selective switching function of the group of capacitors is blocked:
under the condition that the capacitor is discharged completely, the capacitor can be put into the furnace again after n time after being cut off; n is the capacitor discharge time set by the safety automatic device;
the whole group of time conditions of the action, the group of capacitors is not put into the action in the whole group of time, and the capacitors can be put into the action; after the device is started, if the fault disappears, the device is judged to be a whole group of reset after 5 s;
and setting the initial priority of the capacitor to be non-zero, and putting the capacitor into use when the initial priority of the capacitor is set to be non-zero.
It should be noted that the capacitor can be put into use and simultaneously satisfy the above conditions.
Further, wherein the capacitor blocking signal is divided into a temporary blocking signal and a permanent blocking signal:
temporary lockout signals (auto reset), such as capacitor switch overhauls, etc.;
permanent lockout signals (manual reset) such as capacitor protection action, capacitor protection lockout, capacitor over-temperature alarm, capacitor light gas alarm, capacitor over-temperature trip, and capacitor heavy gas trip. It should be noted that the latching signal types are merely exemplary.
In an embodiment, fig. 3 is a flowchart illustrating a main transformer overvoltage crowbar capacitor operation, and specifically, as shown in fig. 3, the step (3) includes the following steps:
(3.1) generating an overvoltage strategy of the selection range by the overvoltage strategy inlet of the main transformer in the circulation selection range, wherein the overvoltage strategy inlet comprises any main transformer overvoltage action in the circulation selection range, and the overvoltage strategy is that the capacitors are switched for the first time without delay and then all capacitors need to be cut off after k time delay; where k is the overvoltage-switching capacitance time interval.
(3.2) in the determined circular selection and cutting range, under the condition that the priority of the overvoltage cutting capacitor main transformer is close to that of the front main transformer, a group of capacitors with the priority of the cuttable capacitor priority being close to that of the front main transformer is cut off;
(3.3) reordering the priority of the overvoltage cutting capacitor main transformer, arranging the priority of the main transformer with the capacitor cut off in action at the end, and storing the priority in a storage unit;
(3.4) if the circulating selection and switching range has overvoltage starting and does not return to the main transformer and the capacitors thrown into the safety automatic device are not completely cut off, turning to the step (3.5), otherwise, turning to the step (3.6);
(3.5) judging whether k time delay is passed, if so, turning to the step 3-2, and if not, turning to the step 3-4;
and (3.6) the logic of the capacitor is cut off in the cycle range.
Optionally, the step (3.1) specifically includes:
main transformer overvoltage judgment logic: if the main transformer low-voltage input capacitor is too much, the main transformer overvoltage is higher than the overvoltage action fixed value of the safety automatic device, and the main transformer overvoltage acts after g time delay; each main transformer is provided with 1 overvoltage action turn, and overvoltage is judged by adopting positive sequence voltage; only under the condition that the low voltage of the main transformer is put into the capacitor, the overvoltage judgment function of the main transformer is opened; wherein g is the overvoltage action delay fixed value of the corresponding safety automatic device.
Specifically, the cycle selection range is divided into the following 3 ranges:
circular selection range 1: under the condition that buses run in parallel, all running main transformers;
circular selection range 2: under the condition that the buses are operated in rows, the operation main transformer is hung on the I-section bus;
the circular selection range 3: and under the condition that the buses are operated in rows, the operation main transformer is hung on the section II buses.
It should be noted that, the above-mentioned cyclic selection and cutting range is divided by the double-bus operation mode, for example, other bus operation modes can also be expanded according to actual situations, which is not described in detail in the embodiment of the present invention, and can be easily obtained by those skilled in the art based on the content of the embodiment.
Optionally, the step (3.2) specifically includes:
1) and (3) sequencing the priorities of main transformer of the overvoltage cutting capacitor:
the safety automatic device performs priority sequencing on the main transformers in the determined cycle selection and switching range according to the main transformer priority fixed value of the overvoltage switching capacitor, the sequencing with the smaller fixed value is forward, the fixed value is set to be zero and does not participate in the priority sequencing, the priority sequencing of the overvoltage switching capacitor main transformers is modified into initial priority sequencing by manually modifying the fixed value every time, and the initial priority sequencing is stored in a storage unit; after the capacitors are switched every time, the priority of the main transformer of the overvoltage switching capacitors is reordered, and the priority of the main transformer of the current switching capacitor is arranged at the end and stored in a storage unit; the safety automatic device obtains the priority sequence of the overvoltage-cutting capacitor main transformer by reading the storage unit.
2) The priority sequence of the capacitors can be switched under each main transformer:
and performing priority ranking on the cut capacitors under each main transformer in the determined cyclic selection and cutting range, wherein the capacitor which is firstly put in is in front of the priority ranking, and the cut capacitor does not participate in the priority ranking.
Compared with the prior art, the method and the device have the following beneficial effects:
the embodiment of the invention comprises a safe automatic device which can realize that the capacitor is put into the device quickly when the voltage drops, and part of the capacitor is cut off if the voltage is higher after the system recovers so as to solve the requirement of the system stability; meanwhile, the safety automatic device is matched with the low-voltage load shedding device, a capacitor is put into the low-voltage load shedding device before action, the load shedding amount can be effectively reduced on the premise of keeping the transient voltage of the system stable, and the safety automatic device has a positive effect on maintaining the operation stability and the economical efficiency of the power system.
The parts of the method in the embodiment of the present invention that are not developed can refer to the corresponding parts of the method in the above embodiment, and are not developed in detail here.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (4)
1. A method with a reactive compensation rapid switching function is characterized by comprising the following steps:
(1) the safety automatic device monitors the bus voltage of the controllable capacitor in real time and judges whether the system has short-circuit fault according to the actual voltage value of the monitored bus; the bus voltage of the controllable capacitor selects voltages on the high-voltage sides of a plurality of main transformers;
(2) when the safety automatic device judges the low-voltage round action of the main transformer, a reactor on the same bus or a parallel bus with the main transformer is cut off, and then a part of capacitors which can be put into the main transformer are selected;
wherein the step (2) comprises:
(2.1) judging the low-voltage turn action of the main transformer;
when the main transformer detects that the voltage is lower than a certain action turn fixed value of the low voltage of the safety automatic device, delaying the time for m, wherein the low voltage corresponds to the action turn; each main transformer is provided with a first low-voltage action round, a second low-voltage action round and a third low-voltage action round, and the first low-voltage action round, the second low-voltage action round and the third low-voltage action round are independent rounds and adopt positive sequence voltage to judge; the first low-voltage action round and the second low-voltage action round open the low-voltage round action judging function only when the system has short-circuit fault, and the third low-voltage wheel is not limited by whether the short-circuit fault occurs or not;
wherein m is a low-voltage action turn delay fixed value corresponding to the safety automatic device;
(2.2) acquiring the number of capacitor sets required to be put into the main transformer low-voltage action turns;
(2.3) if the number of the capacitor banks needing to be put into is nonzero, cutting off all reactors on the same bus or a parallel bus with the main transformer;
(2.4) selecting and putting the capacitors with the same number of groups according to the priority sequence of the capacitors under the main transformer;
wherein the step (2.4) specifically comprises:
(2.41) acquiring the priority sequence of the main transformer capacitors; each group of capacitors under the main transformer is endowed with an initial priority fixed value, the initial priority sequence of each group of capacitors can be determined through fixed value setting, the priority sequence can be modified into the initial priority sequence every time the fixed value is manually modified, and the initial priority sequence is stored in a storage unit; after the capacitors are put into the device for each time of operation, the capacitor banks are subjected to priority ranking again and stored in a storage unit; the safety automatic device obtains capacitor priority sequencing under each main transformer through reading and storing the capacitor priority sequencing in a storage unit;
(2.42) charging a capacitor in accordance with capacitor charging conditions including:
when the capacitor group is overhauled, the corresponding allowable switching pressing plate is withdrawn, and the capacitor group cannot be switched;
judging whether the group of capacitors are in a hot standby state or not under the condition that the capacitors are in the hot standby state, and when the corresponding capacitor switch positions are time-sharing, the capacitors are in the hot standby state and can be put into use;
the capacitor has no relevant blocking signal condition, when the blocking signal exists in the capacitor, the selective switching function of the group of capacitors is blocked:
under the condition that the capacitor is discharged completely, the capacitor can be put into the furnace again after n time after being cut off; n is the capacitor discharge time set by the safety automatic device;
the whole group of time conditions of the action, the group of capacitors is not put into the action in the whole group of time, and the capacitors can be put into the action; after the device is started, if the fault disappears, the device is judged to be a whole group of reset after 5 s;
setting a nonzero condition by the initial priority of the capacitor, and putting the capacitor into operation when the initial priority of the capacitor is set nonzero;
(2.5) re-prioritizing the capacitors, and ranking the priorities of the capacitors which are put into the process at the end and storing the priorities in a storage unit;
(3) after capacitors are put into the system, if the voltage is higher after the system is recovered, 1 group of capacitors are withdrawn after time delay t, if overvoltage starting is not returned, one group of capacitors are withdrawn at time interval t until all main transformers on a bus where the main transformers are located or a parallel bus are returned after overvoltage starting or all the put capacitors are cut off, wherein t is a capacitor withdrawal delay fixed value.
2. The method with the reactive compensation fast switching function according to claim 1, wherein the step (3) specifically comprises the following steps:
(3.1) circulating overvoltage actions of any main transformer in the selection range, namely generating an overvoltage strategy of the selection range, wherein the overvoltage strategy is that the capacitors are switched for the first time without delay, and then all the capacitors are cut off after k time delay; wherein k is the overvoltage-switching capacitance time interval;
(3.2) in the determined circular selection and cutting range, under the condition that the priority of the overvoltage cutting capacitor main transformer is close to that of the front main transformer, a group of capacitors with the priority of the cuttable capacitor priority being close to that of the front main transformer is cut off;
(3.3) reordering the priority of the overvoltage cutting capacitor main transformer, arranging the priority of the main transformer with the capacitor cut off in action at the end, and storing the priority in a storage unit;
(3.4) if the circulating selection and switching range has overvoltage starting and does not return to the main transformer and the capacitors thrown into the safety automatic device are not completely cut off, turning to the step (3.5), otherwise, turning to the step (3.6);
(3.5) judging whether k time delay is passed, if so, turning to the step 3-2, and if not, turning to the step 3-4;
and (3.6) the logic of the over-voltage cut capacitor in the cycle range is finished.
3. The method with the reactive compensation fast switching function according to claim 2, wherein the step (3.1) specifically comprises:
main transformer overvoltage judgment logic: if the main transformer low-voltage input capacitor is too much, the main transformer overvoltage is higher than the overvoltage action fixed value of the safety automatic device, and the main transformer overvoltage acts after g time delay; each main transformer is provided with 1 overvoltage action turn, and overvoltage is judged by adopting positive sequence voltage; only under the condition that the low voltage of the main transformer is put into the capacitor, the overvoltage judgment function of the main transformer is opened; wherein g is an overvoltage action delay fixed value corresponding to the safety automatic device;
the circular selection range comprises:
circular selection range 1: under the condition that buses run in parallel, all running main transformers;
circular selection range 2: under the condition that the buses are operated in rows, the operation main transformer is hung on the I-section bus;
the circular selection range 3: and under the condition that the buses are operated in rows, the operation main transformer is hung on the section II buses.
4. The method with the reactive compensation fast switching function according to claim 3, wherein the step (3.2) specifically comprises:
1) and (3) sequencing the priorities of main transformer of the overvoltage cutting capacitor:
the safety automatic device performs priority sequencing on the main transformers in the determined cycle selection and switching range according to the main transformer priority fixed value of the overvoltage switching capacitor, the sequencing with the smaller fixed value is forward, the fixed value is set to be zero and does not participate in the priority sequencing, the priority sequencing of the overvoltage switching capacitor main transformers is modified into initial priority sequencing by manually modifying the fixed value every time, and the initial priority sequencing is stored in a storage unit; after the capacitors are switched every time, the priority of the main transformer of the overvoltage switching capacitors is reordered, and the priority of the main transformer of the current switching capacitor is arranged at the end and stored in a storage unit; the safety automatic device obtains the priority sequence of the overvoltage cut capacitor main transformer by reading the storage unit;
2) the priority sequence of the capacitors can be switched under each main transformer:
and performing priority ranking on the cut capacitors under each main transformer in the determined cyclic selection and cutting range, wherein the capacitor which is firstly put in is in front of the priority ranking, and the cut capacitor does not participate in the priority ranking.
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| CN111244970A (en) * | 2020-02-28 | 2020-06-05 | 广东华利源电气设备有限公司 | Reactive compensation control device and control method thereof |
| CN114050580A (en) * | 2021-11-10 | 2022-02-15 | 许继集团有限公司 | Voltage regulation method and device for regional-level hundred-percent new energy power system |
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