CN116780639A - Distributed photovoltaic grid-connected control method, device and storage medium - Google Patents
Distributed photovoltaic grid-connected control method, device and storage medium Download PDFInfo
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Abstract
The application provides a distributed photovoltaic grid-connected control method, a device and a storage medium, and relates to the technical field of photovoltaic grid-connected, wherein the method comprises the following steps: obtaining a line current actual measurement value when a switch in the power distribution network trips; comparing the actual measured value of the line current with a protection current setting value, and determining that the switch tripping is fault tripping or fault-free stealing according to a comparison result; when the switch trips to fault trip, determining that the switch belongs to a fault range, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment connected to the line, and transferring power supply through feeder automation; when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control. The application improves the detection accuracy of the tripping fault of the switch, further improves the control accuracy of feeder automation, and can prevent the expansion of the power loss range of the power distribution network.
Description
Technical Field
The application relates to the technical field of photovoltaic grid connection, in particular to a distributed photovoltaic grid connection control method, a distributed photovoltaic grid connection control device and a storage medium.
Background
After the distributed photovoltaic power generation equipment is connected into the power distribution network, the power distribution network structure can be changed into a multi-power-supply structure from a traditional radial structure, if the power distribution network breaks down at this moment, due to the influence of the distributed photovoltaic power generation equipment, an in-loop overcurrent signal of FA (Feeden Autonation) can not meet the judgment condition of an FA fault point, and further the feeder automation can not realize fault isolation and transfer functions, so that the power loss range of the power distribution network is enlarged.
In order to ensure the correct operation of the feeder automation function, the fault range and the power supply range to be recovered are accurately judged through the regional protection based on information interaction and the disconnection protection based on-site information judgment at present, so that the rapid cutting of the distributed photovoltaic power generation equipment and the power supply recovery of the equipment in the power supply range to be recovered are realized. When facing a switch tripping fault, the conventional method generally uniformly considers the switch tripping as the tripping due to the line fault, divides the switch into fault ranges, ignores the condition of no-fault stealing and tripping of the switch, has lower fault detection accuracy, and leads to lower control accuracy of feeder automation, thereby leading to larger power loss range of the power distribution network.
Disclosure of Invention
The application solves the problem of how to improve the detection accuracy of the tripping fault of the switch so as to improve the control accuracy of feeder automation and further prevent the expansion of the power loss range of the power distribution network.
In order to solve the problems, the application provides a distributed photovoltaic grid-connected control method, a distributed photovoltaic grid-connected control device and a storage medium.
In a first aspect, the present application provides a distributed photovoltaic grid-connected control method, including:
obtaining a line current actual measurement value when a switch in the power distribution network trips;
comparing the actual measured value of the line current with a protection current setting value, and determining that the switch tripping is fault tripping or fault-free stealing according to a comparison result;
when the switch tripping is fault tripping, determining that the switch belongs to a fault range, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment of the access line, and carrying out transfer power supply through feeder automation;
when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control.
Optionally, the determining that the switch is tripped as a fault trip or no fault theft trip according to the comparison result includes:
when the measured value of the line current is greater than or equal to the protection current setting value, determining that the switch tripping is fault tripping;
and when the measured value of the line current is smaller than the protection current setting value, determining that the switch trips as fault-free stealth.
Optionally, the protection current setting value includes a short circuit current setting value, an overload current setting value, and a leakage current setting value, and when the line current actual measurement value is greater than or equal to the protection current setting value, determining that the switch trips as fault trips includes:
when the measured value of the line current is larger than or equal to the setting value of the short-circuit current, determining that the switch tripping is short-circuit protection tripping;
when the measured value of the line current is smaller than the setting value of the short-circuit current and is larger than or equal to the setting value of the overload current, judging whether the switch tripping is overload protection tripping according to the variation of the measured value of the line current, wherein the setting value of the overload current is smaller than the setting value of the short-circuit current;
and when the zero sequence component of the actual measurement value of the line current is greater than or equal to the leakage current setting value, determining that the switch tripping is leakage protection tripping.
Optionally, the determining whether the switch tripping is overload protection tripping according to the variation of the measured line current value includes:
acquiring line current actual measurement values at a plurality of continuous acquisition moments when and before the switch trips and line current expected values when the power distribution network normally operates;
determining the actual measured current variation between the actual measured line current values at each two adjacent acquisition moments and the expected current variation between the expected line current values at each two adjacent acquisition moments;
and comparing the actually measured current variation with the expected current variation to determine whether the switch tripping is the overload protection tripping.
Optionally, the comparing the measured current variation and the expected current variation to determine whether the switch trip is the overload protection trip includes:
taking the actually measured current variation between the current collection time and the previous collection time as an actually measured current gradient of the current collection time, and taking the expected current variation between the current collection time and the previous collection time as an expected current gradient of the current collection time;
determining a first function of the expected current gradient with respect to time and a second function of the expected current gradient with respect to time span from the expected current gradients at each acquisition instant; determining a third function of the measured current gradient with respect to the time span according to the measured current gradient at each acquisition time, wherein the time span is the sum of the time and the time interval between every two adjacent acquisition times, and the time interval between every two adjacent acquisition times is the same;
multiplying the first function by the second function to obtain an expected current gradient function; multiplying the first function by the third function to obtain an actual measurement current gradient function;
integrating the expected current gradient function according to time in a preset time interval before the switch trips to obtain an expected current gradient integral value; integrating the actually measured current gradient function according to time to obtain an actually measured current gradient integral value;
determining the ratio between the actual measured current gradient integral value and the expected current gradient integral value to obtain a current gradient correlation value;
judging whether the current gradient interrelation value is in a preset fault threshold value range, and determining whether the switch tripping is overload protection tripping according to a judging result.
Optionally, the determining whether the switch tripping is overload protection tripping according to the judging result includes:
and when the current gradient interrelation value is within the preset fault threshold value range, determining that the switch tripping is the overload protection tripping.
Optionally, after the switch is determined to be tripped by fault or no fault stealth according to the comparison result, the method further comprises:
and recording the times of occurrence of the fault-free steal and jump, and determining that the switch has faults when the times reach a preset time threshold.
In a second aspect, the present application provides a distributed photovoltaic grid-connected control apparatus, including:
the acquisition module is used for acquiring a line current actual measurement value when a switch in the power distribution network trips;
the comparison module is used for comparing the actual measured value of the line current with the setting value of the protection current, and determining that the switch tripping is fault tripping or fault-free stealth tripping according to a comparison result;
the control module is used for determining that the switch belongs to a fault range when the switch trips to fault trip, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment connected to the line, and transferring power supply through feeder automation; when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control.
In a third aspect, the present application provides a distributed photovoltaic grid-connected control apparatus, including a memory and a processor;
the memory is used for storing a computer program;
the processor is configured to implement the distributed photovoltaic grid-connected control method according to the first aspect when executing the computer program.
In a fourth aspect, the present application provides a computer readable storage medium having a computer program stored thereon, which when executed by a processor, implements the distributed photovoltaic grid-tie control method according to the first aspect.
The distributed photovoltaic grid-connected control method, the distributed photovoltaic grid-connected control device and the storage medium have the beneficial effects that: the method comprises the steps of obtaining a line current actual measurement value of a switch in a power distribution network when the switch trips, comparing the line current actual measurement value with a protection current setting value, wherein the protection current setting value can be determined according to the bearing capacity of the power distribution network line, and particularly can represent a trigger current value of the protection action operation of the power distribution network. According to the comparison result, whether the switch tripping is fault tripping or fault-free tripping is judged, the specific condition of the switch tripping can be accurately judged, and the detection accuracy of the switch tripping fault is improved. For example: when the measured value of the line current is greater than or equal to the setting value of the protection current, the tripping of the switch is represented as fault tripping; and when the measured value of the line current is smaller than the setting value of the protection current, the tripping of the switch is indicated to be fault-free and theft-trip. When the switch is tripped due to faults, the switch is divided into a fault range, a combined switching command is output to cut off the distributed photovoltaic power generation equipment connected to the circuit, the feeding automation is determined to be capable of operating normally, fault isolation is carried out through the feeding automation, and power supply for the normal range of the power distribution network is transferred. When the switch does not have fault and steals, the switch is divided into a range to be recovered, a combined switching command is output to cut off the distributed photovoltaic power generation equipment of the access line, normal operation of feed automation is ensured, and power supply is recovered through the feed automation control switch. Aiming at the tripping faults of the switch under different conditions, different feeder automation control processes are adopted, the control accuracy of feeder automation is improved, and the expansion of the power loss range can be avoided.
Drawings
FIG. 1 is a schematic flow chart of a distributed photovoltaic grid-connected control method according to an embodiment of the present application;
FIG. 2 is a flow chart of another method for distributed photovoltaic grid-tie control according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a distributed photovoltaic grid-connected control device according to an embodiment of the present application.
Detailed Description
In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. While the application is susceptible of embodiment in the drawings, it is to be understood that the application may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided to provide a more thorough and complete understanding of the application. It should be understood that the drawings and embodiments of the application are for illustration purposes only and are not intended to limit the scope of the present application.
It should be understood that the various steps recited in the method embodiments of the present application may be performed in a different order and/or performed in parallel. Furthermore, method embodiments may include additional steps and/or omit performing the illustrated steps. The scope of the application is not limited in this respect.
The term "including" and variations thereof as used herein are intended to be open-ended, i.e., including, but not limited to. The term "based on" is based at least in part on. The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "alternative embodiments". Related definitions of other terms will be given in the description below. It should be noted that the terms "first," "second," and the like herein are merely used for distinguishing between different devices, modules, or units and not for limiting the order or interdependence of the functions performed by such devices, modules, or units.
It should be noted that references to "one", "a plurality" and "a plurality" in this disclosure are intended to be illustrative rather than limiting, and those skilled in the art will appreciate that "one or more" is intended to be construed as "one or more" unless the context clearly indicates otherwise.
The names of messages or information interacted between the devices in the embodiments of the present application are for illustrative purposes only and are not intended to limit the scope of such messages or information.
When the Guan Yingu barrier is tripped, the switch needs to be divided into a fault range, and the feeder line cuts off power supply in the fault range during automatic operation. When the switch does not have fault and steals, the switch can be divided into a range to be recovered to supply power, and the switch can be controlled to recover the power supply when the feeder line automatically operates. Therefore, the switch is regarded as the fault trip of the switch, and the power loss range of the power distribution network can be enlarged.
In addition, the switch fault tripping generally comprises short-circuit protection tripping, overload protection tripping and leakage protection tripping, in the prior art, a worker checks fault reasons one by one after the switch tripping, the fault detection efficiency is low, and the fault repairing period is long.
As shown in fig. 1 and fig. 2, in order to solve the above-mentioned problems in the prior art, a distributed photovoltaic grid-connected control method provided by an embodiment of the present application includes:
s100, obtaining a line current actual measurement value when a switch in the power distribution network trips.
Specifically, the actual measurement value of the line current when the switch trips can be collected through a detection device such as a current transformer.
And S200, comparing the actual measured value of the line current with a protection current setting value, and determining that the switch trips as fault trips or fault-free stealth trips according to a comparison result.
Specifically, the switch includes a circuit breaker, a load switch, and the like. The protection current setting value may be a preset current setting value, and the type of the switch tripping is judged according to the comparison result of the line current actual measurement value and the protection current setting value, for example: when the measured value of the line current is larger than or equal to the setting value of the protection current, the conditions such as overload or short circuit of the line current can occur, and the tripping of the switch is determined to be fault tripping; and when the measured value of the line current is smaller than the setting value of the protection current, the protection action cannot occur, and the tripping of the switch can be determined to be fault-free and steal.
S300, when the switch trips to be in fault trip, determining that the switch belongs to a fault range, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment connected to the line, and carrying out transfer power supply through feeder automation;
when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control.
Specifically, after a power distribution network fails, a corresponding switch in the power distribution network trips to isolate the fault and issues a combined switching command. The fault range and the power supply range to be recovered in the power distribution network are determined based on the topology structure and the fault isolation result of the power distribution network, and the specific processing method is the prior art and is not repeated here.
If a breaker at the outlet of the transformer substation trips, the distribution line cannot meet the non-voltage condition due to the fact that the distributed photovoltaic power generation equipment is connected to the distribution network, all levels of switches cannot trip, and then the feeder automation function cannot operate normally. Therefore, when the switch trips, the type of the switch tripping is determined firstly, specifically, fault tripping or no fault stealing and tripping is performed, the distributed photovoltaic power generation equipment which is connected to the line is cut off through the combined switching command, the distributed photovoltaic power generation equipment which needs to be cut off can be specifically the distributed photovoltaic power generation equipment which is connected to the fault range of the power distribution network and the power supply range to be recovered, and the normal range of the power distribution network can be disconnected from the fault range of the power distribution network and the power supply range to be recovered, so that the distributed photovoltaic power generation equipment which is connected to the normal range of the power distribution network does not need to be cut off. After the corresponding distributed photovoltaic power generation equipment is cut off, the feeder automation function can normally operate, and if a switch fault trips, the power is automatically transferred to a normal range of the power distribution network through the feeder; if the switch has no fault skip, the power supply is automatically recovered through the feeder line.
In this embodiment, a measured value of a line current at a switch in the power distribution network when the switch trips is obtained, the measured value of the line current is compared with a setting value of a protection current, the setting value of the protection current can be determined according to the carrying capacity of the power distribution network line, and the setting value of the protection current can specifically represent a trigger current value of the protection action operation of the power distribution network. According to the comparison result, whether the switch tripping is fault tripping or fault-free tripping is judged, the specific condition of the switch tripping can be accurately judged, and the detection accuracy of the switch tripping fault is improved. For example: when the measured value of the line current is greater than or equal to the setting value of the protection current, the tripping of the switch is represented as fault tripping; and when the measured value of the line current is smaller than the setting value of the protection current, the tripping of the switch is indicated to be fault-free and theft-trip. When the switch is tripped due to faults, the switch is divided into a fault range, a combined switching command is output to cut off the distributed photovoltaic power generation equipment connected to the circuit, the feeding automation is determined to be capable of operating normally, fault isolation is carried out through the feeding automation, and power supply for the normal range of the power distribution network is transferred. When the switch does not have fault and steals, the switch is divided into a range to be recovered, a combined switching command is output to cut off the distributed photovoltaic power generation equipment of the access line, normal operation of feed automation is ensured, and power supply is recovered through the feed automation control switch. Aiming at the tripping faults of the switch under different conditions, different feeder automation control processes are adopted, the control accuracy of feeder automation is improved, and the expansion of the power loss range can be avoided.
Optionally, the determining that the switch is tripped as a fault trip or no fault theft trip according to the comparison result includes:
when the measured value of the line current is greater than or equal to the protection current setting value, determining that the switch tripping is fault tripping;
and when the measured value of the line current is smaller than the protection current setting value, determining that the switch trips as fault-free stealth.
Specifically, the protection current setting value may be a current setting value set in advance according to the line load capacity, and may also be understood as a trigger current for the protection operation. Fault tripping may mean tripping of a switch due to a line fault in the distribution network, and fault-free tripping may mean tripping of a switch due to its mechanical properties, etc., without a line fault in the distribution network.
When the measured line current value is greater than or equal to the protection current setting value, the protection action is considered to be triggered at the moment, and the switch tripping can be determined to be fault tripping. When the measured value of the line current is smaller than the setting value of the protection current, the protection action is considered to be triggered at the moment, and the tripping of the switch can be determined to be fault-free stealth.
In the alternative embodiment, the specific condition of the tripping of the switch is judged through the comparison result of the actual measured value of the line current and the setting value of the protection current, and the operation is simple and the efficiency is higher.
Optionally, the protection current setting value includes a short circuit current setting value, an overload current setting value, and a leakage current setting value, and when the line current actual measurement value is greater than or equal to the protection current setting value, determining that the switch trips as fault trips includes:
when the measured value of the line current is larger than or equal to the setting value of the short-circuit current, determining that the switch tripping is short-circuit protection tripping;
when the measured value of the line current is smaller than the setting value of the short-circuit current and is larger than or equal to the setting value of the overload current, judging whether the switch tripping is overload protection tripping according to the variation of the measured value of the line current, wherein the setting value of the overload current is smaller than the setting value of the short-circuit current;
and when the zero sequence component of the actual measurement value of the line current is greater than or equal to the leakage current setting value, determining that the switch tripping is leakage protection tripping.
Specifically, the switch fault tripping includes short-circuit protection tripping, overload protection tripping, leakage protection tripping, and the like.
And comparing the measured line current value with the setting value of the short-circuit current, and determining that the switch is tripped for short-circuit protection when the measured line current value is greater than or equal to the setting value of the short-circuit current, which indicates that the power distribution network line is short-circuited.
If the measured line current value is smaller than the setting value of the short-circuit current, the measured line current value can be compared with the setting value of the overload current, and if the measured line current value is larger than or equal to the setting value of the overload current, the overload of the power distribution network line is possible to occur, but because the instantaneous overload switch of the circuit normally does not trip immediately, whether the tripping of the switch is overload protection tripping can be further judged according to the change condition or the thermal effect of the measured line current value.
And comparing the zero sequence component of the actual measured value of the line current with the leakage current setting value, and when the zero sequence component of the actual measured value of the line current is greater than or equal to the leakage current setting value, indicating that the power distribution network is likely to have leakage faults, so that the tripping of the switch can be determined to be leakage protection tripping.
In the optional embodiment, the specific reason of the line fault can be determined through the comparison result of the actual measured value of the line current and the setting values of various protection currents, so that the fault can be accurately and efficiently positioned by workers, the fault processing efficiency is improved, and the power loss influence caused by the fault of the power distribution network is reduced.
Optionally, the determining whether the switch tripping is overload protection tripping according to the variation of the measured line current value includes:
and obtaining line current actual measurement values at a plurality of continuous acquisition moments when and before the switch trips and line current expected values when the power distribution network normally operates.
Specifically, expected line current values corresponding to different working conditions when the power distribution network normally operates can be determined through calibration in advance, and a corresponding relation between the working condition data and the expected line current values is established. Working condition data of a plurality of acquisition moments (including the switch tripping moment) from the switch tripping moment to the front can be obtained, and the expected value of the line current at the corresponding moment is determined in the corresponding relation, or the expected value of the line current at the corresponding moment is obtained through working condition parameter calculation. And line current actual measurement values from the tripping moment of the switch to a plurality of acquisition moments (including the tripping moment of the switch) are acquired through detection devices such as a current transformer, and the time intervals between adjacent acquisition moments can be the same.
And determining the actual measured current variation between the actual measured line current values at each two adjacent acquisition moments and the expected current variation between the expected line current values at each two adjacent acquisition moments.
Specifically, subtracting the measured value of the line current at the previous acquisition time from the measured value of the line current at the current acquisition time to obtain the measured current variation; subtracting the line current expected value at the previous acquisition time from the line current expected value at the current acquisition time to obtain an expected current variation; the current acquisition time is any one of all the acquisition times.
And comparing the actually measured current variation with the expected current variation to determine whether the switch tripping is the overload protection tripping.
Specifically, if the measured value of the line current at the current acquisition time is greater than the overload protection current, comparing the measured current variation corresponding to the time period between the current acquisition time and the previous acquisition time with the expected current variation, and determining that the power distribution network line is in instantaneous overload when the measured current variation is greater than the expected current variation and the difference between the measured current variation and the expected current variation is greater than a preset threshold. And when the number of the time periods when the instantaneous overload occurs reaches a preset value, determining that the switch tripping is overload protection tripping.
In the optional embodiment, the actual measurement current variation between the actual measurement values of the line currents at every two adjacent collection moments and the expected current variation between the expected values of the line currents at every two adjacent collection moments are calculated, and the instantaneous overload condition of the power distribution network line can be accurately identified by comparing and processing the actual measurement current variation and the expected current variation, so that whether the switch tripping is overload protection tripping or not can be accurately judged.
Optionally, the comparing the measured current variation and the expected current variation to determine whether the switch trip is the overload protection trip includes:
and taking the actually measured current variation between the current acquisition time and the previous acquisition time as an actually measured current gradient of the current acquisition time, and taking the expected current variation between the current acquisition time and the previous acquisition time as an expected current gradient of the current acquisition time.
Specifically, the current acquisition time is any one acquisition time, and the actual measurement value of the line current at the current acquisition time is assumed to be I 1 (t) expected line current value I 2 (t) line current measured value at previous acquisition time is I 1 (t-Deltat), the expected value of line current at the previous acquisition time is I 2 (t- Δt), the measured current variation between the two times is calculated as x (t) =i 1 (t)-I 1 (t- Δt), the expected current change amount between the two moments is y (t) =i 2 (t)-I 2 (t- Δt), the measured current gradient at time t can be determined as x (t), and the expected current gradient at time t as y (t).
Determining a first function of the expected current gradient with respect to time and a second function of the expected current gradient with respect to time span from the expected current gradients at each acquisition instant; and determining a third function of the measured current gradient with respect to the time span according to the measured current gradient at each acquisition time, wherein the time span is the sum of the time and the time interval between every two adjacent acquisition times, and the time interval between every two adjacent acquisition times is the same.
In particular, a first function of the expected current gradient with respect to time may be denoted y (t), a second function of the expected current gradient with respect to time span may be denoted y (t+Δt), a third function of the measured current gradient with respect to time span may be denoted x (t+Δt), t+Δt represents time span, t represents any instant in time, Δt represents time interval.
Multiplying the first function by the second function to obtain an expected current gradient function; multiplying the first function by the third function to obtain an actual measurement current gradient function.
Specifically, the expected current gradient function may be expressed as y (t) ·y (t+Δt), and the measured current gradient function may be expressed as y (t) ·x (t+Δt).
Integrating the expected current gradient function according to time in a preset time interval before the switch trips to obtain an expected current gradient integral value; and integrating the actually measured current gradient function according to time to obtain an actually measured current gradient integral value.
Specifically, the expected current gradient function y (t) ·y (t+Δt) and the measured current gradient function y (t) ·x (t+Δt) are integrated respectively in a preset time interval to obtain an expected current gradient integral value and a measured current gradient integral value.
Determining the ratio between the actual measured current gradient integral value and the expected current gradient integral value to obtain a current gradient correlation value;
judging whether the current gradient interrelation value is in a preset fault threshold value range, and determining whether the switch tripping is overload protection tripping according to a judging result.
Specifically, the expected current gradient function may reflect a correlation between expected current gradients at two adjacent acquisition times, that is, a correlation between an expected current variation at a previous acquisition time and an expected current variation at a current acquisition time, and may be integrated over a preset time interval, and an accumulated value of each expected current gradient function value, that is, an expected current gradient integral value may be determined.
The actual measurement current gradient function can reflect the interrelation between actual measurement current gradients of two adjacent acquisition moments, namely, the interrelation between the actual measurement current variation of the previous acquisition moment and the actual measurement current variation of the current acquisition moment, and can be integrated in a preset time interval to determine the accumulated value of each actual measurement current gradient function value, namely, the actual measurement current gradient integral value.
The ratio between the actual current gradient integral value and the expected current gradient integral value, that is, the current gradient correlation value, may be determined using the expected current gradient integral value as a reference value. When the line current at the tripping moment of the switch is larger than the overload protection current and the current gradient correlation value is in the preset fault threshold value range, the deviation between the actually measured value of the line current and the expected value of the line current is larger, the fact that the power distribution network line is not only in instantaneous overload can be determined, overload is triggered to carry out overload protection, and then the fact that the tripping of the switch is overload protection tripping is determined. The false alarm or missing alarm condition possibly caused by the fault detection by only adopting the actual measured value of the line current at the tripping moment of the switch is avoided, and the detection accuracy of the overload protection of the line is improved.
Optionally, the determining whether the switch tripping is overload protection tripping according to the judging result includes:
and when the current gradient interrelation value is within the preset fault threshold value range, determining that the switch tripping is the overload protection tripping.
Specifically, the preset fault threshold range may be determined according to an actual bearing capacity of the power distribution network line, and the like.
Optionally, after the switch is determined to be tripped by fault or no fault stealth according to the comparison result, the method further comprises:
and recording the times of occurrence of the fault-free steal and jump, and determining that the switch has faults when the times reach a preset time threshold.
Specifically, when the switch frequently fails and is stolen, the switch is determined to fail, and timely maintenance or replacement of the switch is prompted.
As shown in fig. 3, a distributed photovoltaic grid-connected control device provided by an embodiment of the present application includes:
the acquisition module is used for acquiring a line current actual measurement value when a switch in the power distribution network trips;
the comparison module is used for comparing the actual measured value of the line current with the setting value of the protection current, and determining that the switch tripping is fault tripping or fault-free stealth tripping according to a comparison result;
the control module is used for determining that the switch belongs to a fault range when the switch trips to fault trip, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment connected to the line, and transferring power supply through feeder automation; when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control.
The distributed photovoltaic grid-connected control device of the present embodiment is used to implement the distributed photovoltaic grid-connected control method described above, and the advantages of the distributed photovoltaic grid-connected control device compared with the prior art are the same as those of the distributed photovoltaic grid-connected control method described above compared with the prior art, and are not described herein again.
It should be noted that, in the distributed photovoltaic grid-connected control apparatus provided in the foregoing embodiment, when the functions of the distributed photovoltaic grid-connected control apparatus are implemented, only the division of the functional modules is used for illustrating, in practical application, the allocation of the functions may be implemented by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules, so as to implement all or part of the functions described above. In addition, the system and method embodiments provided in the foregoing embodiments belong to the same concept, and specific implementation processes of the system and method embodiments are detailed in the method embodiments, which are not repeated herein.
The distributed photovoltaic grid-connected control device provided by the other embodiment of the application comprises a memory and a processor; the memory is used for storing a computer program; the processor is configured to implement the distributed photovoltaic grid-connected control method as described above when executing the computer program.
A further embodiment of the present application provides a computer readable storage medium having a computer program stored thereon, which when executed by a processor, implements a distributed photovoltaic grid-tie control method as described above.
An electronic device that can be a server or a client of the present application will now be described, which is an example of a hardware device that can be applied to aspects of the present application. Electronic devices are intended to represent various forms of digital electronic computer devices, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the applications described and/or claimed herein.
The electronic device includes a computing unit that can perform various appropriate actions and processes according to a computer program stored in a Read Only Memory (ROM) or a computer program loaded from a storage unit into a Random Access Memory (RAM). In the RAM, various programs and data required for the operation of the device may also be stored. The computing unit, ROM and RAM are connected to each other by a bus. An input/output (I/O) interface is also connected to the bus.
The computer system may include a client and a server. The client and server are typically remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.
Those skilled in the art will appreciate that implementing all or part of the above-described methods in accordance with the embodiments may be accomplished by way of a computer program stored on a computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), or the like. In the present application, the units described as separate units may or may not be physically separate, and units displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment of the present application. In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
Although the application is disclosed above, the scope of the application is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the application, and these changes and modifications will fall within the scope of the application.
Claims (10)
1. The distributed photovoltaic grid-connected control method is characterized by comprising the following steps of:
obtaining a line current actual measurement value when a switch in the power distribution network trips;
comparing the actual measured value of the line current with a protection current setting value, and determining that the switch tripping is fault tripping or fault-free stealing according to a comparison result;
when the switch tripping is fault tripping, determining that the switch belongs to a fault range, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment of the access line, and carrying out transfer power supply through feeder automation;
when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control.
2. The method according to claim 1, wherein determining that the switch is tripped by fault or no fault theft according to the comparison result comprises:
when the measured value of the line current is greater than or equal to the protection current setting value, determining that the switch tripping is fault tripping;
and when the measured value of the line current is smaller than the protection current setting value, determining that the switch trips as fault-free stealth.
3. The distributed photovoltaic grid-connected control method according to claim 2, wherein the protection current setting value includes a short-circuit current setting value, an overload current setting value, and a leakage current setting value, and wherein determining that the switch is tripped as a fault trip when the line current measured value is greater than or equal to the protection current setting value includes:
when the measured value of the line current is larger than or equal to the setting value of the short-circuit current, determining that the switch tripping is short-circuit protection tripping;
when the measured value of the line current is smaller than the setting value of the short-circuit current and is larger than or equal to the setting value of the overload current, judging whether the switch tripping is overload protection tripping according to the variation of the measured value of the line current, wherein the setting value of the overload current is smaller than the setting value of the short-circuit current;
and when the zero sequence component of the actual measurement value of the line current is greater than or equal to the leakage current setting value, determining that the switch tripping is leakage protection tripping.
4. The method according to claim 3, wherein the step of determining whether the switch trip is an overload protection trip according to the amount of change in the measured line current value comprises:
acquiring line current actual measurement values at a plurality of continuous acquisition moments when and before the switch trips and line current expected values when the power distribution network normally operates;
determining the actual measured current variation between the actual measured line current values at each two adjacent acquisition moments and the expected current variation between the expected line current values at each two adjacent acquisition moments;
and comparing the actually measured current variation with the expected current variation to determine whether the switch tripping is the overload protection tripping.
5. The method according to claim 4, wherein comparing the measured current variation with the expected current variation, and determining whether the switch trip is the overload protection trip comprises:
taking the actually measured current variation between the current collection time and the previous collection time as an actually measured current gradient of the current collection time, and taking the expected current variation between the current collection time and the previous collection time as an expected current gradient of the current collection time;
determining a first function of the expected current gradient with respect to time and a second function of the expected current gradient with respect to time span from the expected current gradients at each acquisition instant; determining a third function of the measured current gradient with respect to the time span according to the measured current gradient at each acquisition time, wherein the time span is the sum of the time and the time interval between every two adjacent acquisition times, and the time interval between every two adjacent acquisition times is the same;
multiplying the first function by the second function to obtain an expected current gradient function; multiplying the first function by the third function to obtain an actual measurement current gradient function;
integrating the expected current gradient function according to time in a preset time interval before the switch trips to obtain an expected current gradient integral value; integrating the actually measured current gradient function according to time to obtain an actually measured current gradient integral value;
determining the ratio between the actual measured current gradient integral value and the expected current gradient integral value to obtain a current gradient correlation value;
judging whether the current gradient interrelation value is in a preset fault threshold value range, and determining whether the switch tripping is overload protection tripping according to a judging result.
6. The method according to claim 5, wherein determining whether the switch trip is an overload protection trip according to the determination result comprises:
and when the current gradient interrelation value is within the preset fault threshold value range, determining that the switch tripping is the overload protection tripping.
7. The method according to any one of claims 2 to 6, wherein after determining that the switch is tripped as a fault trip or no fault skip, further comprising:
and recording the times of occurrence of the fault-free steal and jump, and determining that the switch has faults when the times reach a preset time threshold.
8. A distributed photovoltaic grid-tie control device, comprising:
the acquisition module is used for acquiring a line current actual measurement value when a switch in the power distribution network trips;
the comparison module is used for comparing the actual measured value of the line current with the setting value of the protection current, and determining that the switch tripping is fault tripping or fault-free stealth tripping according to a comparison result;
the control module is used for determining that the switch belongs to a fault range when the switch trips to fault trip, outputting a combined switching command to cut off the distributed photovoltaic power generation equipment connected to the line, and transferring power supply through feeder automation; when the switch trips to be in fault-free stealing, the switch is determined to belong to a power supply range to be recovered, the distributed photovoltaic power generation equipment connected to the line is cut off by outputting a combined switching command, and the power supply of the switch is recovered through feeder automation control.
9. The distributed photovoltaic grid-connected control device is characterized by comprising a memory and a processor;
the memory is used for storing a computer program;
the processor for implementing the distributed photovoltaic grid-tie control method according to any one of claims 1 to 7 when executing the computer program.
10. A computer readable storage medium, wherein a computer program is stored on the storage medium, which when executed by a processor, implements the distributed photovoltaic grid-connected control method according to any one of claims 1 to 7.
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101388543A (en) * | 2008-10-29 | 2009-03-18 | 国网电力科学研究院 | Non-failure valve tripping criteria recognizing breaking point based on local measurement |
| CN102737917A (en) * | 2011-04-02 | 2012-10-17 | 三信国际电器上海有限公司 | Circuit breaker used for over-current protection |
| WO2013185455A1 (en) * | 2012-06-15 | 2013-12-19 | 中国电力科学研究院 | Low voltage ride through detection device for grid-connected photovoltaic inverter |
| CN106549355A (en) * | 2016-11-08 | 2017-03-29 | 西安交通大学 | A kind of high-speed reclosure method with chopper jump identification ability |
| WO2017166735A1 (en) * | 2016-03-31 | 2017-10-05 | 国电南瑞科技股份有限公司 | Power-grid self-healing system and self-healing logic thereof in 110kv chain power-supply mode |
| CN107240958A (en) * | 2017-08-02 | 2017-10-10 | 国网上海市电力公司 | A kind of switch jump processing method for the standby throwing of network |
| CN109613422A (en) * | 2018-12-06 | 2019-04-12 | 西安理工大学 | It is a kind of for inhibiting the circuit breaker trip moment control method of secondary arc current |
| CN113872160A (en) * | 2021-08-25 | 2021-12-31 | 国网河北省电力有限公司电力科学研究院 | Distributed power source linkage switching system of power distribution network |
| CN113985195A (en) * | 2021-10-13 | 2022-01-28 | 深圳供电局有限公司 | Method and system for judging circuit breaker stealing tripping based on power grid fault time sequence |
-
2023
- 2023-08-25 CN CN202311075892.7A patent/CN116780639B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101388543A (en) * | 2008-10-29 | 2009-03-18 | 国网电力科学研究院 | Non-failure valve tripping criteria recognizing breaking point based on local measurement |
| CN102737917A (en) * | 2011-04-02 | 2012-10-17 | 三信国际电器上海有限公司 | Circuit breaker used for over-current protection |
| WO2013185455A1 (en) * | 2012-06-15 | 2013-12-19 | 中国电力科学研究院 | Low voltage ride through detection device for grid-connected photovoltaic inverter |
| WO2017166735A1 (en) * | 2016-03-31 | 2017-10-05 | 国电南瑞科技股份有限公司 | Power-grid self-healing system and self-healing logic thereof in 110kv chain power-supply mode |
| CN106549355A (en) * | 2016-11-08 | 2017-03-29 | 西安交通大学 | A kind of high-speed reclosure method with chopper jump identification ability |
| CN107240958A (en) * | 2017-08-02 | 2017-10-10 | 国网上海市电力公司 | A kind of switch jump processing method for the standby throwing of network |
| CN109613422A (en) * | 2018-12-06 | 2019-04-12 | 西安理工大学 | It is a kind of for inhibiting the circuit breaker trip moment control method of secondary arc current |
| CN113872160A (en) * | 2021-08-25 | 2021-12-31 | 国网河北省电力有限公司电力科学研究院 | Distributed power source linkage switching system of power distribution network |
| CN113985195A (en) * | 2021-10-13 | 2022-01-28 | 深圳供电局有限公司 | Method and system for judging circuit breaker stealing tripping based on power grid fault time sequence |
Non-Patent Citations (2)
| Title |
|---|
| FERAS ALASALI ET AL.: "Advanced Coordination Method for Overcurrent Protection Relays Using New Hybrid and Dynamic Tripping Characteristics for Microgrid", 《IEEE ACCESS》, vol. 10, pages 127377 - 127396 * |
| 涂崎等: "一种基于通信保护融合的分布式电源切除方法", 《电工电气》, no. 10, pages 22 - 27 * |
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