CN-121769801-B - Energy integration differential protection method and system based on distributed parameter model

CN121769801BCN 121769801 BCN121769801 BCN 121769801BCN-121769801-B

Abstract

The energy integration differential protection method and system based on the distribution parameter model comprises the steps of collecting three-phase voltage and three-phase current instantaneous values of the line on the side and the opposite side in real time, calculating three-phase current calculated values of the line on the same time based on the three-phase voltage and the three-phase current instantaneous values of the line on the opposite side, calculating to obtain three-phase current differential flow based on the three-phase current differential flow collected in real time and the three-phase current calculated values of the line on the same time, calculating three-phase differential flow action quantity based on the three-phase current differential flow, and utilizing the three-phase differential flow action quantity to form an energy integration differential protection action criterion, and performing differential protection when the three-phase differential flow action quantity meets the differential protection action criterion. The problems of frequency deviation, harmonic waves and the like after the traditional Berhelone phasor differential protection is subjected to the faults of new energy, flexible direct current and other power electronic equipment are solved, and the differential protection action performance under the new energy transmission scene is improved.

Inventors

ZHENG YUPING
WU TONGHUA
WANG CHAOMING
HONG FENG
SUN ZHIPAN
PU HONGFEI
ZHENG XIAOJIANG

Assignees

国电南瑞科技股份有限公司
国网电力科学研究院有限公司
国网江苏省电力有限公司电力科学研究院

Dates

Publication Date: 20260508
Application Date: 20260304

Claims (14)

1. The energy integration differential protection method based on the distributed parameter model is characterized by comprising the following steps of: step 1, collecting three-phase voltage and three-phase current instantaneous values of the current side and the opposite side of a line in real time; step 2, three-phase current calculated values at the same moment on the current side are calculated based on three-phase voltage and three-phase current instantaneous values on the opposite side of the line; Step 3, calculating to obtain a three-phase current difference stream based on the real-time acquired local side three-phase current instantaneous value and the local side three-phase current calculation value at the same moment; step 4, calculating three-phase differential current motion quantity based on the three-phase current differential current; and 5, utilizing the three-phase differential flow motion quantity to form an energy integration differential protection motion criterion, and when the three-phase differential flow motion quantity meets the differential protection motion criterion, performing differential protection motion, wherein the differential protection motion criterion is shown in the following formula: in the formula, Is a fixed threshold; In order to provide a braking coefficient, 、、 Respectively is 、、 The action quantity of the differential flow of the three phases, 、 And the non-fault phase difference flow and the fault phase difference flow are obtained according to the Berlong algorithm when the single-phase earth faults occur respectively.
2. The energy integration differential protection method based on the distributed parameter model according to claim 1, wherein the method comprises the following steps: in step 1, three-phase voltage and current sampling instantaneous values of the m-side protection device at each moment are collected and set as 、、、、、 Obtaining three-phase voltage and current instantaneous value sampling values at the same time on the opposite side of the line, namely the n side through a signal transmission channel, and setting the three-phase voltage and current instantaneous value sampling values as 、、、、、。
3. The energy integration differential protection method based on the distributed parameter model according to claim 2, wherein the method comprises the following steps: in step 2, the instantaneous value of the voltage and the current at the moment t on the opposite side of the line is substituted into the Berlong model equation to calculate the calculated value of the three-phase current at the moment t on the m side 、、。
4. A method for energy integration differential protection based on a distributed parameter model as defined in claim 1, 2 or 3, wherein: in step 3, the three-phase current difference flow is calculated at time t according to the following formula: In the middle of Is a three-phase differential flow at the moment t on the m side, For the three-phase sampling current at the moment t on the m side, Calculating a three-phase current calculation value at the moment t on the m side according to the Beroreron model; Take the value of Or (b) Or (b) Respectively represent 、、 Three phases.
5. The energy integration differential protection method based on the distributed parameter model according to claim 4, wherein the method comprises the following steps: in step 4, the three-phase differential flow motion is calculated according to the following formula: Wherein the method comprises the steps of Is the action quantity of the three-phase differential flow, Take the value of Or (b) Or (b) Respectively represent 、、 Three phases, T is a cycle time.
6. The energy integration differential protection method based on the distributed parameter model according to claim 1, wherein the method comprises the following steps: fixed threshold The method comprises the following steps: Wherein the method comprises the steps of , Taking 50HZ and T as a cycle time, The differential protection is fixed.
7. The energy integration differential protection system based on the distributed parameter model comprises a line bilateral electric quantity acquisition module, a local side current calculation module, a three-phase current differential flow and differential flow action quantity calculation module and a differential protection judgment module, and is characterized in that: the line bilateral electric quantity acquisition module acquires three-phase voltage and three-phase current instantaneous values of the line local side and the opposite side in real time; the current estimation module at the side is used for calculating a three-phase current calculated value at the same moment at the side based on the three-phase voltage and the three-phase current instantaneous value at the opposite side of the circuit; The three-phase current differential flow and differential flow action quantity calculating module is used for calculating a three-phase current differential flow based on the real-time acquired local side three-phase current instantaneous value and the local side three-phase current calculation value at the same moment and further calculating the three-phase differential flow action quantity; The differential protection judging module utilizes the three-phase differential flow action quantity to form an energy integration differential protection action criterion, and when the three-phase differential flow action quantity meets the differential protection action criterion, the differential protection action is performed, wherein the energy integration differential protection action criterion is shown in the following formula: in the formula, Is a fixed threshold; In order to provide a braking coefficient, 、、 Respectively is 、、 Differential flow motion of three phases; 、 and the non-fault phase difference flow and the fault phase difference flow are obtained according to the Berlong algorithm when the single-phase earth faults occur respectively.
8. The energy integrating differential protection system based on a distributed parameter model according to claim 7, wherein the line bilateral electric quantity acquisition module acquires line local side and contralateral side three-phase voltage and three-phase current instantaneous values in real time, and comprises: collecting three-phase voltage and current sampling instantaneous values of the protection device at each moment at the side, namely the m side, is set as 、、、、、 Obtaining three-phase voltage and current instantaneous value sampling values at the same time on the opposite side of the line, namely the n side through a signal transmission channel, and setting the three-phase voltage and current instantaneous value sampling values as 、、、、、。
9. The energy integrating differential protection system based on a distributed parameter model according to claim 8, wherein the current calculation module on the side calculates three-phase current calculation values on the same side based on three-phase voltage and three-phase current instantaneous values on the opposite side of the line, and comprises: Line opposite side t moment voltage current the instantaneous values are substituted into the berlong model equation, calculating three-phase current calculation value at m side t moment 、、。
10. The energy integrating differential protection system based on a distributed parameter model as claimed in claim 7, 8 or 9, wherein the three-phase current differential flow and differential current motion amount calculation module calculates a three-phase current differential flow based on the real-time acquired instantaneous value of the current side and the calculated value of the current side at the same time, comprising: the three-phase current difference stream is calculated at time t according to the following formula: In the middle of Is a three-phase differential flow at the moment t on the m side, For the three-phase sampling current at the moment t on the m side, Calculating a three-phase current calculation value at the moment t on the m side according to the Beroreron model; Take the value of Or (b) Or (b) Respectively represent 、、 Three phases.
11. The energy integrating differential protection system based on the distributed parameter model of claim 10, wherein calculating the three-phase differential current motion based on the three-phase current differential current comprises: calculating the three-phase differential flow motion quantity according to the following steps: Wherein the method comprises the steps of Is the action quantity of the three-phase differential flow, Take the value of Or (b) Or (b) Respectively represent 、、 Three phases, T is a cycle time.
12. The distributed parameter model-based energy integrating differential protection system of claim 7, wherein: fixed threshold The method comprises the following steps: Wherein the method comprises the steps of , Taking 50HZ and T as a cycle time, The differential protection is fixed.
13. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out the steps of the method according to any one of claims 1-6.
14. Computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, realizes the steps of the method according to any of claims 1-6.

Description

Energy integration differential protection method and system based on distributed parameter model Technical Field The invention belongs to the technical field of relay protection, relates to differential protection technology, and particularly relates to an energy integration differential protection method and system based on a distributed parameter model. Background With the improvement of the new energy duty ratio of the electric power system, the power supply characteristic of the system is deeply changed, the traditional distance type principle and the direction type principle are greatly influenced, and the system is forced to exit from operation even when some new energy is sent out of a channel. The current differential protection has the advantages of full-line quick-action, absolute selectivity, no influence of system oscillation and the like, and is the most important main protection in the current power system. With the further development of new energy, long-distance transmission scenes such as Sha Gehuang, deep-open sea wind power and the like are gradually developed, and the influence of capacitance current of a transmission line on differential protection is gradually not negligible. And the phasor differential protection based on the Berhelson model calculates a differential flow by using a line distribution parameter model, and is not influenced by transient state and steady state capacitance current of the power transmission line. However, the sensitivity of the berlong differential criterion is affected by the single-phase earth short-circuited non-faulted phase imbalance differential flow within the zone. Meanwhile, the protection criterion of phasor differential protection based on the Berlong model is to extract the power frequency phasors, however, the characteristics of frequency deviation, harmonic waves and the like of the fault current of the new energy transmission line often lead to difficult extraction of the power frequency phasors based on the Fourier algorithm, and the differential protection performance is reduced. The differential protection can solve the problem that the protection performance of the differential protection in the new energy transmission line is reduced, and is particularly characterized in that when the new energy is transmitted through the long line, the capacitance current is not negligible, and the differential protection performance is affected. In the traditional Berhelson differential protection, when a single-phase earth fault exists, a calculation error leads to a differential flow of a non-fault phase, and protection misoperation can be caused. The traditional Berhelone differential protection adopts a phasor differential mode, the response characteristics of new energy, flexible direct current and other power electronic equipment after the AC system is in fault are highly influenced by a control strategy, and the problems of frequency deviation, harmonic waves and the like can exist, so that the power frequency phasor is difficult to extract, and the sensitivity and the quick action of the differential protection are influenced. Disclosure of Invention In view of the above technical problems in the prior art, the present invention provides an energy integration differential protection method based on a distributed parameter model, so as to improve the performance of differential protection actions. In order to solve the technical problems, the invention adopts the following technical scheme: In a first aspect, the invention discloses an energy integration differential protection method based on a distributed parameter model, which comprises the following steps: step 1, collecting three-phase voltage and three-phase current instantaneous values of the current side and the opposite side of a line in real time; step 2, three-phase current calculated values at the same moment on the current side are calculated based on three-phase voltage and three-phase current instantaneous values on the opposite side of the line; Step 3, calculating to obtain a three-phase current difference stream based on the real-time acquired local side three-phase current instantaneous value and the local side three-phase current calculation value at the same moment; step 4, calculating three-phase differential current motion quantity based on the three-phase current differential current; And 5, utilizing the three-phase differential flow motion quantity to form an energy integration differential protection motion criterion, and performing differential protection motion when the three-phase differential flow motion quantity meets the differential protection motion criterion. It is further preferred that the composition comprises, In step 1, three-phase voltage and current sampling instantaneous values of the m-side protection device at each moment are collected and set as、、、、、Obtaining three-phase voltage and current instantaneous value sampling values at the same time on t