CN116914701A - Distribution network current protection applicability analysis method and device containing distributed photovoltaic - Google Patents

Distribution network current protection applicability analysis method and device containing distributed photovoltaic Download PDF

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Publication number
CN116914701A
CN116914701A CN202310861505.6A CN202310861505A CN116914701A CN 116914701 A CN116914701 A CN 116914701A CN 202310861505 A CN202310861505 A CN 202310861505A CN 116914701 A CN116914701 A CN 116914701A
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China
Prior art keywords
current
distribution network
power distribution
protection
current protection
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CN202310861505.6A
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Chinese (zh)
Inventor
刘博�
梁伟宸
赵志宇
王亚娟
李烜
田琪
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State Grid Corp of China SGCC
North China Electric Power Research Institute Co Ltd
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State Grid Corp of China SGCC
North China Electric Power Research Institute Co Ltd
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Priority to CN202310861505.6A priority Critical patent/CN116914701A/en
Publication of CN116914701A publication Critical patent/CN116914701A/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/30—Circuit design
    • G06F30/36—Circuit design at the analogue level
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/04—Power grid distribution networks
    • 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
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
    • 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
    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
    • H02J2300/20—The dispersed energy generation being of renewable origin
    • H02J2300/22—The renewable source being solar energy
    • H02J2300/24—The renewable source being solar energy of photovoltaic origin
    • 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
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Power Engineering (AREA)
  • Evolutionary Computation (AREA)
  • Geometry (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention discloses a method and a device for analyzing the applicability of current protection of a power distribution network containing distributed photovoltaic, and relates to the technical field of analysis of the applicability of current protection, wherein the method comprises the following steps: establishing an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; determining short-circuit current at the starting end of a power distribution network line according to the power distribution network equivalent circuit model; determining short-circuit current at the tail end of a power distribution network line according to the power distribution network equivalent circuit model; generating a sensitivity analysis result according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and the sensitivity threshold; according to the current value, the setting current value, the total length of the distribution network line and the protection range threshold value at the three-section current protection device when the metallic two-phase short circuit occurs at the tail end of the distribution network line, a protection range analysis result is generated.

Description

Distribution network current protection applicability analysis method and device containing distributed photovoltaic
Technical Field
The invention relates to the technical field of current protection applicability analysis, in particular to a method and a device for analyzing the current protection applicability of a power distribution network containing distributed photovoltaic.
Background
This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.
The novel power system gradually presents high-proportion new energy and high-power electronization characteristics in the construction process, and brings new challenges to reliable power supply, safety and stability and economic operation of a power grid. The photovoltaic power supply is connected into the power distribution network in a distributed, multi-point, scattered and dense mode, so that the traditional relay protection and automation system are greatly affected. The high-proportion distributed photovoltaic is connected into the power distribution network, so that the structure and the characteristics of the power distribution network are greatly changed, the network is changed from a single-ended network to a multi-terminal power supply network, the fault current characteristics of the power distribution network are also changed when faults occur, the traditional fault calculation method and relay protection fixed values are not applicable any more, the problems of current protection refusal or misoperation and the like are possibly caused, and the safe operation of the power distribution network is affected. At present, a complete method for analyzing and judging the applicability of the current protection of the power distribution network with high-proportion distributed photovoltaic access is not available.
Disclosure of Invention
The embodiment of the invention provides a method for analyzing the applicability of current protection of a power distribution network containing distributed photovoltaic, which is used for analyzing the applicability of the current protection of the power distribution network containing distributed photovoltaic by calculating the sensitivity and the protection range of the current protection, and comprises the following steps:
establishing an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device;
determining short-circuit current at the beginning of a power distribution network line when a metallic three-phase short circuit occurs at the beginning of the power distribution network line according to the power distribution network equivalent circuit model;
determining short-circuit current of the tail end of the power distribution network line when metallic two-phase short-circuit occurs at the tail end of the power distribution network line according to the power distribution network equivalent circuit model;
generating a sensitivity analysis result of current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection;
and generating a protection range analysis result of the current protection according to the current value, the setting current value, the total length of the distribution network line and a preset protection range threshold of the current protection at the three-section current protection device when the metallic two-phase short circuit occurs at the tail end of the distribution network line.
The embodiment of the invention also provides a distribution network current protection applicability analysis device containing distributed photovoltaic, which is used for realizing applicability analysis of the distribution network current protection containing the distributed photovoltaic by calculating the sensitivity and the protection range of the current protection, and comprises the following steps:
the model building module is used for building an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device;
the first short-circuit current determining module is used for determining the short-circuit current at the beginning of the power distribution network line when the beginning of the power distribution network line is in metallic three-phase short circuit according to the power distribution network equivalent circuit model;
the second short-circuit current determining module is used for determining the short-circuit current of the tail end of the power distribution network line when the tail end of the power distribution network line is in metallic two-phase short circuit according to the power distribution network equivalent circuit model;
the sensitivity analysis module is used for generating a sensitivity analysis result of the current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection;
the protection range analysis module is used for generating a protection range analysis result of the current protection according to the current value, the setting current value, the total length of the distribution network line and the preset protection range threshold of the current protection at the three-section current protection device when the metallic two-phase short circuit occurs at the tail end of the distribution network line.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the computer program is executed by the processor to realize the method for analyzing the current protection applicability of the power distribution network containing the distributed photovoltaic.
The embodiment of the invention also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program realizes the analysis method for the current protection applicability of the power distribution network containing the distributed photovoltaic when being executed by a processor.
The embodiment of the invention also provides a computer program product, which comprises a computer program, wherein the computer program is executed by a processor to realize the analysis method for the current protection applicability of the power distribution network containing the distributed photovoltaic.
Compared with the prior art, the method and the device have the advantages that the equivalent circuit model of the power distribution network is built according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device; determining short-circuit current at the beginning of a power distribution network line when a metallic three-phase short circuit occurs at the beginning of the power distribution network line according to the power distribution network equivalent circuit model; determining short-circuit current of the tail end of the power distribution network line when metallic two-phase short-circuit occurs at the tail end of the power distribution network line according to the power distribution network equivalent circuit model; generating a sensitivity analysis result of current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection; according to the current value, the setting current value, the total length of the distribution network line and the preset protection range threshold value of the current protection at the three-section current protection device when the metal two-phase short circuit occurs at the tail end of the distribution network line, the protection range analysis result of the current protection is generated, and the applicability analysis of the current protection on the distribution network containing the distributed photovoltaic can be realized.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a flow chart of a method for analyzing the applicability of current protection of a power distribution network containing distributed photovoltaic in an embodiment of the invention;
FIG. 2 is an equivalent circuit diagram of a distributed photovoltaic in an embodiment of the present invention;
FIG. 3 is a schematic node diagram of an equivalent circuit model of a power distribution network in an embodiment of the invention;
FIG. 4 is a flow chart of determining the minimum protection range of the current protection I segment in an embodiment of the invention;
fig. 5 is a block diagram of a device for analyzing current protection applicability of a power distribution network including distributed photovoltaic according to an embodiment of the present invention;
fig. 6 is a block diagram of a specific example of a current protection applicability analysis device for a power distribution network including distributed photovoltaic according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention provide a method, an apparatus, a computing device, a computer readable storage medium, and a computer program product for analyzing the applicability of current protection of a power distribution network including distributed photovoltaics.
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention will be described in further detail with reference to the accompanying drawings. The exemplary embodiments of the present invention and their descriptions herein are for the purpose of explaining the present invention, but are not to be construed as limiting the invention.
The following first describes the terminology involved in the present invention.
Setting current (fixed value, setting current value): setting current is an important term in relay protection. The setting value is a value calculated according to the bearing capacity of a circuit and a power grid by manually defining a standard value which is compared with an actual current when relay protection judges tripping.
Three-section type current protection device: when a short circuit occurs in a line, a current protection device is operated in response to an increase in current in a three-stage current protection (step-wise current protection) manner when a current flows through a predetermined value.
Three-section type current protection: the three-section protection of the current is a set of protection formed by mutually matching current quick-break protection (current protection section I), time-limited current quick-break protection (current protection section II) and time-limited overcurrent protection (current protection section III). Wherein, the current protection I section: the setting current value of the current protection section I (instantaneous current quick break protection) is set according to the principle that the setting current is larger than the maximum short-circuit current of the end of the protected line. The protection range is greatly influenced by the operation mode and the fault type of the system.
The protection scope is as follows: generally refers to the protection scope of relay protection. It is expected that the range covered by protection beyond which non-unit protection will not act. The protection range of the current protection section I is usually smaller and is 15-50% of the whole length of the circuit. Current protection section II: the purpose of setting the current protection II section (time-limited current quick-break protection) is to make up the defect of the protection of the I section. Current protection section III: the protection range of the current protection section III (time-limited overcurrent protection) is large, and the current protection section III is usually used as a near backup protection of a line and a far backup protection of an adjacent next line.
Sensitivity (sensitivity): referring to the capability of the current protection device to react to fault conditions within a prescribed protection range, the sensitivity is typically expressed in terms of a sensitivity coefficient.
Current protection applicability: the embodiment of the invention characterizes the applicability of the current protection by the sensitivity and the protection range of the current protection, and judges the applicability of the current protection by adopting a mode of combining the sensitivity and the protection range.
Aiming at the defects of the prior art, the embodiment of the invention realizes the applicability analysis of the current protection of the power distribution network with the distributed photovoltaic by calculating the sensitivity and the protection range of the current protection, the embodiment of the invention provides a method for analyzing the applicability of the current protection of the power distribution network with the distributed photovoltaic, and fig. 1 is a flow chart of the method for analyzing the applicability of the current protection of the power distribution network with the distributed photovoltaic in the embodiment of the invention, and as shown in fig. 1, the method for analyzing the applicability of the current protection of the power distribution network with the distributed photovoltaic provided by the embodiment of the invention comprises the following steps:
step 101, establishing an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device;
102, determining short-circuit current at the beginning of a power distribution network line when a metallic three-phase short circuit occurs at the beginning of the power distribution network line according to an equivalent circuit model of the power distribution network;
step 103, determining the short-circuit current of the tail end of the power distribution network line when the tail end of the power distribution network line is in metallic two-phase short circuit according to the power distribution network equivalent circuit model;
104, generating a sensitivity analysis result of current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection;
and 105, generating a protection range analysis result of the current protection according to the current value, the setting current value, the total length of the distribution network line and a preset protection range threshold of the current protection at the three-section current protection device when the metallic two-phase short circuit occurs at the tail end of the distribution network line.
In one embodiment, setting the current value includes: the current value of the current protection I section, the current value of the current protection II section and the current value of the current protection III section.
In one embodiment, a distribution network line is analyzed according to actual line conditions, and various distribution network parameters based on the distribution network line are determined, wherein the distribution network line comprises distributed photovoltaic and three-section type current protection devices.
In one embodiment, an equivalent circuit model of the power distribution network is established according to the actual condition of the power distribution network line and the parameters of the power distribution network, and an ideal voltage source can be set for the distributed photovoltaic, namely the power supply side at the upstream of the transformer, wherein the voltage of the ideal voltage source can be set according to the actual rated voltage, and the frequency can be set to be 50Hz. For the transformer and the distribution line, an equivalent circuit is established according to the resistance and the reactance of the transformer and the distribution line, wherein the equivalent circuit comprises a total impedance Z=R+jX connected in series; for a load, expressed in terms of a given active power and reactive power. Fig. 2 is an equivalent circuit diagram of a distributed photovoltaic in the embodiment of the present invention, as shown in fig. 2, because positive and negative sequence currents output by a photovoltaic power supply are controlled by voltage of a grid-connected point, the positive and negative sequence currents can be equivalent to voltage-controlled current sources controlled by the voltage of the grid-connected point, thereby forming an equivalent circuit of the distributed photovoltaic power distribution network.Is a photovoltaic positive sequence current, < >>Is a photovoltaic negative sequence current,/->The voltage is the voltage of a photovoltaic grid-connected point; the photovoltaic positive sequence current and the photovoltaic negative sequence current are functions of the voltage of the photovoltaic grid-connected point, the functional relation is shown in the formula in figure 2, and the photovoltaic positive sequence current and the photovoltaic negative sequence current are controlled by the voltage of the photovoltaic grid-connected point.
In one embodiment, generating a sensitivity analysis result of the current protection according to a short-circuit current at a start of the power distribution network line, a short-circuit current at an end of the power distribution network line, a setting current value, and a preset sensitivity threshold of the current protection includes:
determining the sensitivity coefficient of the current protection section I according to the short-circuit current at the starting end of the power distribution network line and the setting current value of the current protection section I;
determining the sensitivity coefficient of the current protection II section according to the short-circuit current at the tail end of the power distribution network line and the setting current value of the current protection II section;
determining the sensitivity coefficient of the current protection III section according to the short-circuit current at the tail end of the power distribution network line and the setting current value of the current protection III section;
and generating a sensitivity analysis result of the current protection according to the sensitivity coefficient of the current protection I section, the sensitivity coefficient of the current protection II section, the sensitivity coefficient of the current protection III section and a preset sensitivity threshold value of the current protection.
In the present embodiment, a power flow calculation method may be used to calculate a value required for the sensitivity check, for example: calculating short-circuit current of a fault point when metallic three-phase short circuit occurs at an outlet (starting end) of the distribution line; and calculating the short-circuit current of the fault point when the metallic two-phase short circuit occurs at the tail end of the distribution line.
In the present embodiment, the sensitivity coefficient K for sensitivity of current protection sen To measure:
wherein I is k For short-circuit current, three-phase short-circuit current at the outlet of a protected line is adopted when the current protection I section setting current value is judged, and two-phase short-circuit current at the tail end of the protected line is adopted when the current protection II and III section setting current value is judged; i set The current value comprises a current protection I section current value, a current protection II section current value and a current protection III section current value.
In this embodiment, the preset current protection segment I sensitivity threshold may be 1, the segment ii sensitivity threshold may be 1.3, and the segment iii sensitivity threshold may be 1.5. And when the calculated sensitivities of the current protection sections I, II and III are all larger than the preset sensitivity threshold value of the current protection, the sensitivities are considered to pass the check.
In one embodiment, generating a protection range analysis result of current protection according to a current value, a setting current value, a total length of a power distribution network line and a preset protection range threshold of current protection at a three-section current protection device when a metallic two-phase short circuit occurs at a power distribution network line end includes:
determining the position of the distribution network line where the metallic two-phase short circuit occurs when the current value at the three-section current protection device is equal to the set current value of the current protection section I;
and generating a protection range analysis result of the current protection according to the impedance value between the position and the starting end of the power distribution network line, the current value at the three-section current protection device when the tail end of the power distribution network line is in metallic two-phase short circuit, the setting current value, the total length of the power distribution network line and a preset protection range threshold value of the current protection.
In this embodiment, the value required for the protection range check needs to be calculated. The following is the calculation of the values required for the current protection segment I verification analysis:
fig. 3 is a schematic node diagram of an equivalent circuit model of a power distribution network according to an embodiment of the present invention, where, as shown in fig. 3, a node at a head end (start end) of a line is set as a node 1, a node at an end is set as a node Z, any node in the line is set as a node i, a node next to the node i is set as a node j, and an impedance between the two nodes is set as a constant value Z ij . In order to facilitate the calculation of the protection range, a mobile node s is added between the node i and the node j; let Z be is ＝kZ ij K takes a value of 0 to 1 and increases by t (step size) each time.
And when the distribution line node s is in metallic two-phase short circuit, protecting the current at the installation position. Is arranged at a distribution line node s 0 Protection of the current I at the installation site in the event of a metallic two-phase short circuit 1 Equal to the constant value I of the current protection I section Iset By usingThe following procedure determines s 0 Fig. 4 is a flowchart for determining a minimum protection range of a current protection section I in the embodiment of the present invention, and as shown in fig. 4, a power distribution network equation with z+1 nodes is established based on the generated power distribution network equivalent circuit model; initially setting i=1, k=0; the current at the installation position of the protection can be solved by adopting a tide calculation method, namely, the current value at the three-section type current protection device is judged, whether the current value at the three-section type current protection device is equal to the setting current value of the current protection section I or not is judged, if the current value at the three-section type current protection device is not equal and k is not 1, t is increased, and 1 is added; solving the current at the installation position of the protection by adopting a tide calculation method, judging whether the current value at the three-section type current protection device is equal to the set current value of the current protection section I or not until the current value at the three-section type current protection device is equal to the set current value of the current protection section I, determining the values of I and k, and further determining s 0 Is a position of (c).
In one embodiment, according to s 0 The method comprises the steps of generating a protection range analysis result of current protection by impedance values between the position of the power distribution network line start end, current values at the three-section type current protection device when metallic two-phase short circuit occurs at the power distribution network line end, setting current values, total length of the power distribution network line and a preset protection range threshold value of the current protection, wherein the method comprises the following steps:
according to s 0 The minimum protection range of the current protection I section is determined by the impedance value between the position of the power distribution network line start end and the total length of the power distribution network line;
and generating a protection range analysis result of the current protection according to the minimum protection range of the current protection I section, the current value of the three-section current protection device when the tail end of the power distribution network line is in metallic two-phase short circuit, the setting current value of the current protection II section, the setting current value of the current protection III section and a preset protection range threshold value of the current protection.
In the present embodiment, the node s is determined 0 After determining the positions of node 1 and node s 0 Impedance value Z between 1s0 The minimum protection range is:
wherein z is p Line impedance per unit length, L is the total length of the line.
In this embodiment, the calculation of the protection range analysis and verification required value of the current protection sections II and III is as follows: and when the metallic two-phase short circuit occurs at the tail end of the distribution line, protecting the current at the installation position, namely, the current value at the three-section type current protection device.
In this embodiment, the threshold value of the protection range of the I segment may be set to 15% of the total line length, and the minimum protection range R of the I segment is protected by current min When the protection range is larger than the threshold value specified by the check, the protection range is considered to pass the check. Setting the threshold value of the protection range of the sections II and III to be 100% of the whole length of the line. When the calculated distribution line end is in metallic two-phase short circuit, the current at the protection installation position is larger than the setting current value of the sections II and III, the sections II and III can protect the whole length of the line, namely the analysis result of the protection range of the sections II and III of the current protection is that the current passes the check.
In summary, when the sensitivity and the protection range pass the check, the current protection setting current value is considered to pass the applicability judgment.
It should be noted that although the operations of the method of the present invention are depicted in the drawings in a particular order, this does not require or imply that the operations must be performed in that particular order or that all of the illustrated operations be performed in order to achieve desirable results. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step to perform, and/or one step decomposed into multiple steps to perform.
The embodiment of the invention also provides a device for analyzing the current protection applicability of the power distribution network containing the distributed photovoltaic, which is described in the following embodiment. Because the principle of the device for solving the problems is similar to that of the method for analyzing the current protection applicability of the power distribution network containing the distributed photovoltaic, the implementation of the device can be referred to the implementation of the method for analyzing the current protection applicability of the power distribution network containing the distributed photovoltaic, and the repetition is omitted.
Fig. 5 is a block diagram of a device for analyzing current protection applicability of a power distribution network including distributed photovoltaic according to an embodiment of the present invention. As shown in fig. 5, a power distribution network current protection applicability analysis device 500 including distributed photovoltaic provided by the present invention includes:
the model building module 501 is configured to build an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device;
the first short-circuit current determining module 502 is configured to determine a short-circuit current at a start of a power distribution network line when a metallic three-phase short circuit occurs at the start of the power distribution network line according to an equivalent circuit model of the power distribution network;
a second short-circuit current determining module 503, configured to determine, according to the power distribution network equivalent circuit model, a short-circuit current at the end of the power distribution network line when a metallic two-phase short circuit occurs at the end of the power distribution network line;
the sensitivity analysis module 504 is configured to generate a sensitivity analysis result of the current protection according to a short-circuit current at a start of the power distribution network line, a short-circuit current at an end of the power distribution network line, a setting current value, and a preset sensitivity threshold of the current protection;
the protection range analysis module 505 is configured to generate a protection range analysis result of current protection according to a current value, a set current value, a total length of the power distribution network line, and a preset protection range threshold of current protection at the three-stage current protection device when a metallic two-phase short circuit occurs at the end of the power distribution network line.
In one embodiment, setting the current value includes: the current value of the current protection I section, the current value of the current protection II section and the current value of the current protection III section.
In one embodiment, the sensitivity analysis module 504 is specifically configured to:
determining the sensitivity coefficient of the current protection section I according to the short-circuit current at the starting end of the power distribution network line and the setting current value of the current protection section I;
determining the sensitivity coefficient of the current protection II section according to the short-circuit current at the tail end of the power distribution network line and the setting current value of the current protection II section;
determining the sensitivity coefficient of the current protection III section according to the short-circuit current at the tail end of the power distribution network line and the setting current value of the current protection III section;
and generating a sensitivity analysis result of the current protection according to the sensitivity coefficient of the current protection I section, the sensitivity coefficient of the current protection II section, the sensitivity coefficient of the current protection III section and a preset sensitivity threshold value of the current protection.
In one embodiment, the protection scope analysis module 505 is specifically configured to:
determining the position of the distribution network line where the metallic two-phase short circuit occurs when the current value at the three-section current protection device is equal to the set current value of the current protection section I;
and generating a protection range analysis result of the current protection according to the impedance value between the position and the starting end of the power distribution network line, the current value at the three-section current protection device when the tail end of the power distribution network line is in metallic two-phase short circuit, the setting current value, the total length of the power distribution network line and a preset protection range threshold value of the current protection.
In one embodiment, the protection scope analysis module 505 is specifically configured to:
determining the minimum protection range of the current protection section I according to the impedance value between the position and the starting end of the distribution network line and the total length of the distribution network line;
and generating a protection range analysis result of the current protection according to the minimum protection range of the current protection I section, the current value of the three-section current protection device when the tail end of the power distribution network line is in metallic two-phase short circuit, the setting current value of the current protection II section, the setting current value of the current protection III section and a preset protection range threshold value of the current protection.
Fig. 6 is a block diagram of a specific example of a current protection applicability analysis device for a power distribution network including distributed photovoltaic according to an embodiment of the present invention, as shown in fig. 6, a model building module 501, a first short-circuit current determining module 502, and a second short-circuit current determining module 503 may be used as a calculation module, and may be further divided into an instruction input unit, a model generating unit, and a calculation unit, and a sensitivity analysis module 504 and a protection range analysis module 505 may be used as protection analysis judgment modules.
In this embodiment, the instruction input unit determines that the type of the numerical value in the power distribution network needs to be calculated, the model generating unit determines to generate a power distribution network model of z nodes or z+1 nodes according to the instruction, and the calculating unit iteratively calculates the numerical value required by the protection analysis and judgment module according to the calculation instruction and the generated model.
The values required for the protection analysis and judgment module are summarized as follows: (1) When metallic three-phase short circuit occurs at the outlet of the distribution line, short circuit current at a fault point; (2) When metallic two-phase short circuit occurs at the tail end of the distribution line, short circuit current of a fault point; (3) When metallic two-phase short circuit occurs at the tail end of the distribution line, protecting the current at the installation position; (4) minimum protection range of I section.
Compared with the prior art, the method and the device have the advantages that the equivalent circuit model of the power distribution network is determined according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device; determining short-circuit current at the beginning of a power distribution network line when a metallic three-phase short circuit occurs at the beginning of the power distribution network line according to the power distribution network equivalent circuit model; determining short-circuit current of the tail end of the power distribution network line when metallic two-phase short-circuit occurs at the tail end of the power distribution network line according to the power distribution network equivalent circuit model; generating a sensitivity analysis result of current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection; according to the current value, the setting current value, the total length of the distribution network line and the preset protection range threshold value of the current protection at the three-section current protection device when the metal two-phase short circuit occurs at the tail end of the distribution network line, the protection range analysis result of the current protection is generated, the sensitivity and the protection range analysis of the current protection of the distribution network containing the distributed photovoltaic can be realized, and further the analysis and judgment of the applicability of the current protection are realized.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the computer program is executed by the processor to realize the method for analyzing the current protection applicability of the power distribution network containing the distributed photovoltaic.
The embodiment of the invention also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program realizes the analysis method for the current protection applicability of the power distribution network containing the distributed photovoltaic when being executed by a processor.
The embodiment of the invention also provides a computer program product, which comprises a computer program, wherein the computer program is executed by a processor to realize the analysis method for the current protection applicability of the power distribution network containing the distributed photovoltaic.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (10)

1. The utility model provides a distribution network current protection suitability analysis method that contains distributed photovoltaic which characterized in that includes:
establishing an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device;
determining short-circuit current at the beginning of a power distribution network line when a metallic three-phase short circuit occurs at the beginning of the power distribution network line according to the power distribution network equivalent circuit model;
determining short-circuit current of the tail end of the power distribution network line when metallic two-phase short-circuit occurs at the tail end of the power distribution network line according to the power distribution network equivalent circuit model;
generating a sensitivity analysis result of current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection;
and generating a protection range analysis result of the current protection according to the current value, the setting current value, the total length of the distribution network line and a preset protection range threshold of the current protection at the three-section current protection device when the metallic two-phase short circuit occurs at the tail end of the distribution network line.
2. The method of claim 1, wherein the setting the current value comprises: the current value of the current protection I section, the current value of the current protection II section and the current value of the current protection III section.
3. The method of claim 2, wherein generating the sensitivity analysis result of the current protection based on the short-circuit current at the start of the distribution network line, the short-circuit current at the end of the distribution network line, the set current value, and the preset sensitivity threshold of the current protection comprises:
determining the sensitivity coefficient of the current protection section I according to the short-circuit current at the starting end of the power distribution network line and the setting current value of the current protection section I;
determining the sensitivity coefficient of the current protection II section according to the short-circuit current at the tail end of the power distribution network line and the setting current value of the current protection II section;
determining the sensitivity coefficient of the current protection III section according to the short-circuit current at the tail end of the power distribution network line and the setting current value of the current protection III section;
and generating a sensitivity analysis result of the current protection according to the sensitivity coefficient of the current protection I section, the sensitivity coefficient of the current protection II section, the sensitivity coefficient of the current protection III section and a preset sensitivity threshold value of the current protection.
4. The method of claim 2, wherein generating the protection range analysis result of the current protection according to the current value at the three-stage current protection device, the set current value, the total length of the distribution network line and the preset protection range threshold of the current protection when the metallic two-phase short circuit occurs at the end of the distribution network line comprises:
determining the position of the distribution network line where the metallic two-phase short circuit occurs when the current value at the three-section current protection device is equal to the set current value of the current protection section I;
and generating a protection range analysis result of the current protection according to the impedance value between the position and the starting end of the power distribution network line, the current value at the three-section current protection device when the tail end of the power distribution network line is in metallic two-phase short circuit, the setting current value, the total length of the power distribution network line and a preset protection range threshold value of the current protection.
5. The method of claim 4, wherein generating the protection range analysis result of the current protection according to the impedance value between the position and the start of the distribution network line, the current value at the three-stage current protection device when the end of the distribution network line is in a metallic two-phase short circuit, the set current value, the total length of the distribution network line and the preset protection range threshold of the current protection comprises:
determining the minimum protection range of the current protection section I according to the impedance value between the position and the starting end of the distribution network line and the total length of the distribution network line;
and generating a protection range analysis result of the current protection according to the minimum protection range of the current protection I section, the current value of the three-section current protection device when the tail end of the power distribution network line is in metallic two-phase short circuit, the setting current value of the current protection II section, the setting current value of the current protection III section and a preset protection range threshold value of the current protection.
6. The utility model provides a contain distribution network current protection suitability analytical equipment of distributing type photovoltaic which characterized in that includes:
the model building module is used for building an equivalent circuit model of the power distribution network according to the actual condition of the power distribution network line; the power distribution network circuit comprises a distributed photovoltaic and three-section type current protection device;
the first short-circuit current determining module is used for determining the short-circuit current at the beginning of the power distribution network line when the beginning of the power distribution network line is in metallic three-phase short circuit according to the power distribution network equivalent circuit model;
the second short-circuit current determining module is used for determining the short-circuit current of the tail end of the power distribution network line when the tail end of the power distribution network line is in metallic two-phase short circuit according to the power distribution network equivalent circuit model;
the sensitivity analysis module is used for generating a sensitivity analysis result of the current protection according to the short-circuit current at the beginning of the power distribution network line, the short-circuit current at the end of the power distribution network line, the setting current value and a preset sensitivity threshold of the current protection;
the protection range analysis module is used for generating a protection range analysis result of the current protection according to the current value, the setting current value, the total length of the distribution network line and the preset protection range threshold of the current protection at the three-section current protection device when the metallic two-phase short circuit occurs at the tail end of the distribution network line.
7. The apparatus of claim 6, wherein the tuning the current value comprises: the current value of the current protection I section, the current value of the current protection II section and the current value of the current protection III section.
8. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 1 to 5 when executing the computer program.
9. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when executed by a processor, implements the method of any of claims 1 to 5.
10. A computer program product, characterized in that the computer program product comprises a computer program which, when executed by a processor, implements the method of any of claims 1 to 5.
CN202310861505.6A 2023-07-13 2023-07-13 Distribution network current protection applicability analysis method and device containing distributed photovoltaic Pending CN116914701A (en)

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