CN-122026471-A - Active power distribution network distributed power supply admittance capacity calculation method and device

CN122026471ACN 122026471 ACN122026471 ACN 122026471ACN-122026471-A

Abstract

A method for calculating admittance capacity of a distributed power supply of an active power distribution network comprises the steps of dividing grid-connected positions of an inversion type distributed power supply IIDG in a circuit into three areas including an upstream area, a range and a downstream area by taking a protection installation position as a reference point, respectively setting values of a current quick-break protection I section, a delay current quick-break protection II section and a timing over-current protection III section according to a setting principle of three-section current protection, respectively establishing sensitivity check inequality of the current protection I section, the current protection II section and the current protection III section according to the setting values of the sections and combining output characteristics of the IIDG under different fault types, and obtaining admittance capacity constraint of the IIDG of each area through the inequality. According to the method, by means of a three-section type current protection principle, a complex algorithm is not required to be introduced, the calculation process is clear and reliable, popularization and application in actual power distribution network protection setting are easy, and feasible technical support is provided for safe and stable operation of the active power distribution network under high-proportion distributed power supply access.

Inventors

LIANG WEICHEN
MA XINCHENG
LI GUOWU
LI HUI
WANG ZEZHONG
LIU SHEN
ZONG JIN

Assignees

国网冀北电力有限公司电力科学研究院
国家电网有限公司

Dates

Publication Date: 20260512
Application Date: 20251209

Claims (15)

1. A method for calculating the admission capacity of a distributed power supply of an active power distribution network, comprising the following steps: Dividing grid-connected positions of an inversion type distributed power supply IIDG in a line into three areas of protection upstream, protection within a range and protection downstream by taking a protection installation position as a reference point; setting the setting values of a current quick-break protection I section, a delay current quick-break protection II section and a timing over-current protection III section according to a setting principle of three-section current protection; and respectively establishing sensitivity verification inequality of the current protection I section, the current protection II section and the current protection III section according to the setting values of the sections and the output characteristics of the IIDGs under different fault types, and obtaining the admission capacity constraint of the IIDGs of the areas through the inequality.
2. The active power distribution network distributed power admission capacity calculation method according to claim 1, further comprising: constructing an equivalent output model according to the grid-connected point positive sequence voltage drop condition of the IIDG under different fault types; Obtaining the output characteristics of the IIDG under different fault types according to the equivalent output model; the equivalent output model comprises a constant-current state model aiming at three-phase short-circuit faults and an intermediate state model aiming at two-phase inter-phase short-circuit faults.
3. The method for calculating the admission capacity of a distributed power supply of an active power distribution network according to claim 2, wherein the step of respectively establishing the sensitivity check inequality of the current protection sections I, II and III according to the setting values of the sections and the output characteristics of the IIDG under different fault types comprises: respectively establishing the sensitivity and selectivity verification conditions of the current protection sections I, II and III according to the setting values of the sections; and establishing sensitivity verification inequality of the I section, the II section and the III section of the current protection according to the output characteristics of the IIDG under different fault types and the verification conditions.
4. A method for calculating the admission capacity of a distributed power source of an active power distribution network according to claim 3, wherein establishing the check condition of the sensitivity and selectivity of the current protection I segment according to the setting value of each segment comprises: When a three-phase interphase short-circuit fault occurs at the protection outlet, the phase current amplitude is required to be larger than the setting value of the current protection I section.
5. A method for calculating the admission capacity of a distributed power source of an active power distribution network according to claim 3, wherein establishing the check condition of the sensitivity and selectivity of the current protection II segment according to the setting value of each segment comprises: The setting value of the current protection II section of the current line is larger than the setting value of the current protection I section of the next line.
6. A method for calculating the admission capacity of a distributed power source of an active power distribution network according to claim 3, wherein establishing the check condition of the sensitivity and selectivity of the current protection II segment according to the setting value of each segment comprises: the setting value of the current protection II section of the current line is smaller than the amplitude of the current of the two-phase interphase short circuit fault at the tail end of the line.
7. A method for calculating the admission capacity of a distributed power source of an active power distribution network according to claim 3, wherein establishing the check condition of the sensitivity and selectivity of the current protection III segment according to the setting value of each segment comprises: the setting value of the current protection III section of the current line is smaller than the minimum short-circuit current when the two-phase interphase short circuit occurs at the tail end of the line.
8. The method for calculating the admission capacity of a distributed power source of an active power distribution network according to claim 1, wherein the setting value of the current quick-break protection section I according to the setting principle of the three-section current protection comprises: Setting by the following model: ; In the above-mentioned description of the invention, To disregard the maximum fault phase current at the end of the line when a three-phase short circuit fault occurs at IIDG, For the current protection segment I reliability coefficient, Setting value of the current protection I section.
9. The method for calculating the admission capacity of the distributed power supply of the active power distribution network according to claim 1, wherein the setting value of the delay current quick-break protection section II is set according to the setting principle of the three-section current protection comprises: ; In the above-mentioned description of the invention, Setting a value for the current quick break of the next section of line, For the current protection II segment reliability coefficient, Setting value of the current protection II section.
10. The method for calculating the admission capacity of the distributed power supply of the active power distribution network according to claim 1, wherein the setting value of the delay current quick-break protection section II is set according to the setting principle of the three-section current protection comprises: ; In the above-mentioned description of the invention, In order to eliminate the minimum fault phase current when the end of the line of the IIDG is subjected to two-phase interphase short circuit fault, K sen is sensitivity, Setting value of the current protection II section.
11. The method for calculating the admission capacity of a distributed power source of an active power distribution network according to claim 1, wherein the setting value of the over-current protection section III is set according to the setting principle of three-section current protection, comprising: ; In the above formula, I L.max is the maximum load current of the present line, K f is the return coefficient of the current relay for the current protection III section reliability coefficient, Setting value for the current protection III section.
12. An active power distribution network distributed power admission capacity computing device, the device comprising: The relation construction module is used for dividing the grid-connected position of the inversion type distributed power supply IIDG in the circuit into three areas of protection upstream, protection range and protection downstream by taking the protection installation position as a reference point; The fixed value calculation module is used for respectively setting the setting values of the current quick-break protection I section, the delay current quick-break protection II section and the fixed time limit overcurrent protection III section according to the setting principle of the three-section current protection; And the capacity determining module is used for respectively establishing sensitivity verification inequality of the current protection I section, the current protection II section and the current protection III section according to the setting value of each section and the output characteristics of the IIDG under different fault types, and obtaining the admission capacity constraint of each area IIDG through the inequality.
13. An electronic 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 11 when executing the computer program.
14. 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 11.
15. A computer program product comprising computer programs/instructions which, when executed by a processor, implement the steps of the method of any of claims 1 to 11.

Description

Active power distribution network distributed power supply admittance capacity calculation method and device Technical Field The application relates to the field of protection and control of power distribution networks of power systems, in particular to a method and a device for calculating the admission capacity of a distributed power supply of an active power distribution network. Background The urban distribution network is positioned at the terminals of the power grid, namely the power transmission, the power transformation, the power distribution and the power utilization, and directly faces to the power users, and bears the important responsibility of providing safe, reliable and high-quality electric energy for the users. With the gradual expansion of urban scale, the load density of the urban power distribution network is continuously increased, and the requirement on the power supply reliability is also higher. The urban power distribution network protection is basic work for improving the power supply reliability of the demand side, is a central technical link for realizing the automation of the power distribution network, and is one of important work for ensuring the safe and stable operation of the whole power system. The line faults of the urban distribution network are rapidly removed, the fault line is subjected to targeted maintenance, major power failure accidents caused by the line faults can be avoided, and the power supply reliability is improved. Therefore, the method for researching the protection of the urban power distribution network line has important significance for reducing power failure loss, improving fault rush-repair efficiency and guaranteeing reliable operation of the urban power distribution network. The novel urban distribution network has become an important carrier for renewable energy source high-proportion and distributed access. In recent years, the contradiction between energy crisis, environmental pollution, climate warming and economic rapid development is increasingly prominent, and the acceleration of the development and efficient utilization of renewable energy sources has become an important subject to be solved in the energy field of China. The development direction of clean low carbon is maintained, the renewable energy source is greatly promoted to be absorbed, and the construction of a novel urban power distribution network with gradually improved new energy source ratio is actively promoted. Therefore, the inversion type distributed power supply (INVERTER INTERFACED distributed generator, IIDG) taking the renewable energy source as a core becomes an important component part in the novel urban power distribution network in the future. However, in the event of a grid failure, the output current of the inverted distributed power supply may provide both an out-draw effect for upstream protection and an boost effect for downstream protection. On one hand, the output of the inversion type distributed power supply needs to be considered in the current protection setting process so as to ensure the protection sensitivity and selectivity requirements, and on the other hand, the capacity of the inversion type distributed power supply needs to be regularly limited so as to ensure that the inversion type distributed power supply cannot cause excessive degradation of the protection performance when being connected to a circuit. Disclosure of Invention The application aims to provide a method and a device for calculating the admittance capacity of a distributed power supply of an active power distribution network, which are used for setting a three-section current protection fixed value by utilizing a traditional mode, calculating the capacity constraint inequality of an inversion type distributed power supply in a circuit according to the sensitivity and selectivity requirements of the three-section current protection, determining the relation among the capacities of a plurality of inversion type distributed power supplies in the circuit according to the inequality, and obtaining the capacity constraint of the inversion type distributed power supply. The application provides an active power distribution network distributed power supply admittance capacity calculation method, which specifically comprises the steps of taking a protection installation position as a reference point, dividing grid-connected positions of an inversion type distributed power supply IIDG in a circuit into three areas of upstream protection, a range protection and downstream protection, respectively setting values of a current quick-break protection I section, a delay current quick-break protection II section and a time-limit overcurrent protection III section according to a setting principle of three-section current protection, respectively establishing sensitivity check inequality of the current protection I section, the current protection II section and the current protection III section ac