CN114089107B - Capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding - Google Patents
Capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding Download PDFInfo
- Publication number
- CN114089107B CN114089107B CN202111353402.6A CN202111353402A CN114089107B CN 114089107 B CN114089107 B CN 114089107B CN 202111353402 A CN202111353402 A CN 202111353402A CN 114089107 B CN114089107 B CN 114089107B
- Authority
- CN
- China
- Prior art keywords
- capacitor
- line
- fault
- phase
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000003990 capacitor Substances 0.000 title claims abstract description 47
- 238000010187 selection method Methods 0.000 title claims abstract description 11
- 230000007935 neutral effect Effects 0.000 claims abstract description 15
- 230000000903 blocking effect Effects 0.000 claims description 3
- 238000002955 isolation Methods 0.000 claims description 3
- 230000007257 malfunction Effects 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 12
- 238000010586 diagram Methods 0.000 description 5
- 239000002131 composite material Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention provides a capacitor line selection method for grounding a central point of a transformer substation for single-phase grounding fault treatment, when a system single-phase grounding fault occurs, a capacitor protection receives a grounding fault signal, and when the grounding signal is received, a neutral point switch S is closed after a delay of a plurality of seconds; at this time, the unbalanced current collected by the fault line will change from 0 to，I e The unbalanced current of other outgoing line branches is kept unchanged for rated current of the capacitor; therefore, the protection tripping of the fault line is realized by setting the unbalanced current of each outgoing line protection device. The method is efficient, simple and reliable, is not influenced by system disturbance, is simple to calculate and has high line selection accuracy. Through the method, the normal operation of the capacitor is effectively ensured, and meanwhile, a fault line can be quickly found out and isolated.
Description
Technical Field
The invention belongs to the technical field of relay protection, and particularly relates to a capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding.
Background
When a single-phase grounding fault occurs in the grounding-free system, the prior art mainly comprises the following schemes:
the method comprises the following steps: and (5) a road pulling method. The operation and maintenance personnel selectively open the corresponding switches through experience until the ground fault disappears. This approach is inefficient and affects the power reliability of the normal line.
Scheme II: a composite current judgment method. And vector sum is carried out on the zero sequence current and the compensation current of each feeder line to obtain the composite current of each feeder line, and the fault line is selected by judging the characteristics of the composite current of each feeder line. The method has very high precision requirement on the current transformer, is easily influenced by system disturbance, is complex in calculation and has low line selection accuracy.
In short, the main disadvantages of the prior art are as follows:
1. the efficiency is low, and the power supply reliability is not facilitated;
2. the method has high requirements on equipment precision, is easily influenced by system disturbance, is complex in calculation and has low line selection accuracy.
Disclosure of Invention
Aiming at the defects and shortcomings existing in the prior art, the invention provides a capacitor line selection method for grounding a central point of a transformer substation for single-phase grounding fault treatment, which is efficient, simple and reliable, is not influenced by system disturbance, is simple to calculate and has high line selection accuracy. Through the method, the normal operation of the capacitor is effectively ensured, and meanwhile, a fault line can be quickly found out and isolated.
The technical scheme is as follows:
a capacitor line selection method for single-phase earth fault handling of transformer substation center point grounding, characterized by:
based on take the capacitor structure of central point ground function, include: capacitor C connected to bus, controllable switch S at center point of capacitor, and capacitance C to ground of each outgoing line system an 、C bn 、C cn Wherein n=1, 2, 3 … …;
when the system single-phase earth fault occurs, the capacitor protection receives an earth fault signal, and when the earth fault signal is received, the neutral point switch S (generally 5S) is closed after a delay of a plurality of seconds; at this time, the unbalanced current collected by the fault line will change from 0 toI e The unbalanced current of other outgoing line branches is kept unchanged for rated current of the capacitor; therefore, the protection tripping of the fault line is realized by setting the unbalanced current of each outgoing line protection device.
Further, the action logic of fault isolation is as follows:
when the following criteria are met for a certain line:
wherein: u (U) φ For phase voltage, 3U 0 Three times of self-produced zero sequence voltage, U 2 Is a negative sequence phase voltage, U bs U is the phase voltage blocking value 0bs And U 2bs Voltage locking values of zero sequence and negative sequence respectively, 3I 0 Three times of self-produced zero sequence current, I 0set Setting value for zero sequence current action of the protection device;
then after the protection action delay time T, the fault line protection tripping is carried out on the line;
when the controller of the neutral point switch S of the capacitor collects that the busbar voltage is recovered to be normal, the switch S is disconnected.
Further, by increasing the constant-time-period overcurrent protection constant value, malfunction of protection due to an increase in phase current is prevented.
Further, the zero sequence overcurrent protection action time T is set to be larger than T so as to avoid the tripping time of the fault line.
Compared with the prior art, the invention and the preferable scheme thereof have the beneficial effects that:
aiming at the problem of single-phase grounding fault treatment, the method for selecting the line of the capacitor with the grounded center point is high in efficiency, simple and reliable, is not influenced by system disturbance, is simple to calculate and has high line selecting accuracy. Through the method, the normal operation of the capacitor is effectively ensured, and meanwhile, a fault line can be quickly found out and isolated.
Drawings
The invention is described in further detail below with reference to the attached drawings and detailed description:
fig. 1 is a schematic diagram of a capacitor structure with a center point grounding function according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of protection action logic according to an embodiment of the present invention.
FIG. 3 is a schematic diagram of the capacitor phase currents during normal operation of the system according to the embodiment of the present invention.
FIG. 4 is a schematic diagram of the capacitor phase currents during system fault operation in accordance with an embodiment of the present invention.
Detailed Description
In order to make the features and advantages of the present patent more comprehensible, embodiments accompanied with figures are described in detail below:
as shown in fig. 1, a capacitor structure with a center point grounding function is schematically shown. C in the figure is a capacitor connected to a bus; i.e a 、i b 、i c Three-phase currents of the capacitors a, b and c respectively; i.e n Is capacitor center point current; s is a controllable switch of a capacitor center point; c (C) an 、C bn 、C cn Ground capacitance for each outgoing line system, where n=1, 2, 3 … ….
Working principle:
due to the distributed capacitance C of each outgoing line system to the ground an 、C bn 、C cn Very small, where n=1, 2, 3 … …, so the capacitive current at each line interval is negligible. In the case of a system single-phase metallic ground fault, as shown in fig. 1, taking as an example the occurrence of a single-phase metallic ground at the C-phase k point of the outgoing line 1. As can be seen from the figure, the current at ground point k is the sum of the capacitive currents formed by the full-network non-faulty relatively distributed capacitancesThis value is typically small and difficult to detect. This adds difficulty to the determination of a faulty line by detecting the magnitude of the capacitive current.
Therefore, the invention provides a scheme for increasing the capacitance current of the fault line by switching the neutral point switch S of the capacitor, thereby improving the line selection accuracy, being beneficial to the rapid fault isolation of the system and ensuring the power supply reliability.
The basic design thought is as follows: when the system single-phase earth fault occurs, the capacitor protection receives an earth fault signal, and after receiving the earth fault signal, the neutral point switch S is closed for 5 seconds. After switch S is closed, current I at fault point k k Will consist of two parts:
I K ＝I C +i n
(1)
due to I C It is very small and can be neglected,
wherein: i e For rated current of capacitor, unbalanced current collected by fault line is changed from 0 toThe unbalanced current of the other outgoing legs remains unchanged. Therefore, the protection tripping of the fault line can be realized by setting the unbalanced current of each outgoing line protection device, thereby isolating the fault rapidly and effectively. The action logic is as follows:
wherein: u (U) φ For phase voltage, 3U 0 Three times of self-produced zero sequence voltage, U 2 Is a negative sequence phase voltage, U bs U is the phase voltage blocking value 0bs And U 2bs Voltage locking values of zero sequence and negative sequence respectively, 3I 0 Three times of self-produced zero sequence current, I 0set And setting values for zero-sequence current actions of the protection device. The protection action logic block diagram is shown in fig. 2, wherein T is the protection action delay time.
When the faulty line protection trips, the fault is isolated. At this time, the system voltage is restored to normal. When the controller of the neutral point switch S of the capacitor collects that the busbar voltage is recovered to be normal, the switch S is disconnected.
When the system is operating normally, the capacitor central point switch is in the off state, i n ＝0；i a 、i b 、i c Rated for capacitor current I e The phases are sequentially 120 deg. out of phase with an imbalance current of 0 as shown in figure 3.
I when the system C-phase metallic single-phase earth fault and the capacitor center point switch is in the closed state n ＝3I e 、i c =0. As shown in fig. 4.
As can be seen from the graph, the C-phase current of the capacitor becomes 0, and the A-phase current and the B-phase current increase to the original valuesMultiple times and phase change, and a large unbalanced current occurs. Therefore, in this operating state, measures should be taken for capacitor protection to prevent capacitor protection malfunction.
Thus, in a further optimization design, the present embodiment provides the following measures:
measure one: the over-current protection fixed value of the fixed time limit is improved, and the misoperation of protection caused by the increase of phase current is effectively prevented.
And a second measure: and the zero sequence overcurrent protection action time T is longer than T, so that the tripping time of a fault line is effectively avoided.
Through the method, the normal operation of the capacitor is effectively ensured, and meanwhile, a fault line can be quickly found out and isolated.
The present patent is not limited to the above-mentioned best mode, any person can obtain other various types of capacitor line selection methods for grounding the central point of the transformer substation for single-phase grounding fault treatment and the use methods thereof under the teaching of the present patent, and all equivalent changes and modifications made according to the scope of the present patent application shall be covered by the present patent.
Claims (4)
1. A capacitor line selection method for single-phase earth fault handling of transformer substation neutral point grounding, characterized by:
capacitor structure based on take neutral point ground function, includes: capacitor C connected to bus, controllable switch S of neutral point of capacitor, and capacitance C to ground of each outgoing line system an 、C bn 、C cn Wherein n=1, 2, 3 … …; when the system single-phase earth fault occurs, the capacitor protection receives an earth fault signal, and after receiving the earth fault signal, the capacitor neutral point controllable switch S is closed in a delay of a plurality of seconds; at this time, the unbalanced current collected by the fault line will change from 0 toI e The unbalanced current of other outgoing line branches is kept unchanged for rated current of the capacitor; therefore, the protection tripping of the fault line is realized by setting the unbalanced current of each outgoing line protection device;
the action logic for fault isolation is as follows:
when the following criteria are met for a certain line:
wherein: u (U) φ For phase voltage, 3U 0 Three times of self-produced zero sequence voltage, U 2 Is a negative sequence phase voltage, U bs U is the phase voltage blocking value 0bs And U 2bs Voltage locking values of zero sequence and negative sequence respectively, 3I 0 Three times of self-produced zero sequence current, I 0set Setting value for zero sequence current action of the protection device;
then after the protection action delay time T, the fault line protection tripping is carried out on the line;
and after the controller of the capacitor neutral point controllable switch S collects the busbar voltage to be normal, the switch S is disconnected.
2. The capacitor line selection method for single-phase earth fault handling of substation neutral grounding of claim 1, characterized by: by increasing the fixed value of the over-current protection at the fixed time limit, the malfunction of protection caused by the increase of the phase current is prevented.
3. The capacitor line selection method for single-phase earth fault handling of substation neutral grounding of claim 1, characterized by: the zero sequence overcurrent protection action time T is set to be larger than T so as to avoid the tripping time of a fault line.
4. The capacitor line selection method for single-phase earth fault handling of substation neutral grounding of claim 1, characterized by: when the system single-phase ground fault occurs, the capacitor neutral point controllable switch S is closed after a delay of 5 seconds after receiving the ground signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111353402.6A CN114089107B (en) | 2021-11-16 | 2021-11-16 | Capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111353402.6A CN114089107B (en) | 2021-11-16 | 2021-11-16 | Capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114089107A CN114089107A (en) | 2022-02-25 |
| CN114089107B true CN114089107B (en) | 2023-12-22 |
Family
ID=80300813
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111353402.6A Active CN114089107B (en) | 2021-11-16 | 2021-11-16 | Capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114089107B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116482488B (en) * | 2023-06-16 | 2023-09-22 | 国网山东省电力公司东营供电公司 | Power distribution network ground fault distance measurement method and system based on capacitive transient |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001305176A (en) * | 2000-04-25 | 2001-10-31 | Nippon Kouatsu Electric Co | Grounding point standardizing method for power distribution line |
| CN104535894A (en) * | 2015-01-08 | 2015-04-22 | 国家电网公司 | Small current grounding fault line selection method and device in double-bus operation mode |
| CN205484654U (en) * | 2016-03-23 | 2016-08-17 | 安徽一天电气技术有限公司 | Electric capacity disturbance route selection device |
| CN106154118A (en) * | 2016-09-29 | 2016-11-23 | 武汉科技大学 | A kind of Single-phase Earth-fault Selection in Distribution Systems and positioner and method |
| CN205720528U (en) * | 2016-06-30 | 2016-11-23 | 上海宏力达信息技术股份有限公司 | A kind of smart grounding fault small area analysis amplifying device |
| CN106443339A (en) * | 2016-09-28 | 2017-02-22 | 南京能迪电气技术有限公司 | Method for selecting wire after single-phase grounding of ungrounded system |
| CN108120897A (en) * | 2017-12-14 | 2018-06-05 | 国网安徽省电力有限公司蚌埠供电公司 | A kind of distribution single-phase grounding selecting method based on three-phase current unbalance degree computation model |
| CN108152683A (en) * | 2018-01-10 | 2018-06-12 | 济南大学 | Based on the earth fault line selection method for helping increasing principle |
| CN109669095A (en) * | 2019-01-21 | 2019-04-23 | 济南大学 | A kind of isolated neutral system fault line selection method for single-phase-to-ground fault |
| EP3544135A1 (en) * | 2018-03-21 | 2019-09-25 | Siemens Aktiengesellschaft | Method and device for determining a faulty line in a power system compensation grid |
| CN112436493A (en) * | 2020-11-26 | 2021-03-02 | 广东电网有限责任公司佛山供电局 | Single-phase earth fault centralized protection method of small-resistance earth system |
| CN112684288A (en) * | 2020-12-10 | 2021-04-20 | 国网陕西省电力公司西咸新区供电公司 | Method for realizing small-current single-phase grounding line selection by utilizing three-phase fault signal current |
| CN113258544A (en) * | 2021-04-13 | 2021-08-13 | 李景禄 | Compensation type intelligent resistance ground fault processing method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103545796A (en) * | 2013-09-16 | 2014-01-29 | 国家电网公司 | Single-phase grounding fault handling device and method for power distribution network with non-effectively grounded neutral points |
-
2021
- 2021-11-16 CN CN202111353402.6A patent/CN114089107B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001305176A (en) * | 2000-04-25 | 2001-10-31 | Nippon Kouatsu Electric Co | Grounding point standardizing method for power distribution line |
| CN104535894A (en) * | 2015-01-08 | 2015-04-22 | 国家电网公司 | Small current grounding fault line selection method and device in double-bus operation mode |
| CN205484654U (en) * | 2016-03-23 | 2016-08-17 | 安徽一天电气技术有限公司 | Electric capacity disturbance route selection device |
| CN205720528U (en) * | 2016-06-30 | 2016-11-23 | 上海宏力达信息技术股份有限公司 | A kind of smart grounding fault small area analysis amplifying device |
| CN106443339A (en) * | 2016-09-28 | 2017-02-22 | 南京能迪电气技术有限公司 | Method for selecting wire after single-phase grounding of ungrounded system |
| CN106154118A (en) * | 2016-09-29 | 2016-11-23 | 武汉科技大学 | A kind of Single-phase Earth-fault Selection in Distribution Systems and positioner and method |
| CN108120897A (en) * | 2017-12-14 | 2018-06-05 | 国网安徽省电力有限公司蚌埠供电公司 | A kind of distribution single-phase grounding selecting method based on three-phase current unbalance degree computation model |
| CN108152683A (en) * | 2018-01-10 | 2018-06-12 | 济南大学 | Based on the earth fault line selection method for helping increasing principle |
| EP3544135A1 (en) * | 2018-03-21 | 2019-09-25 | Siemens Aktiengesellschaft | Method and device for determining a faulty line in a power system compensation grid |
| CN109669095A (en) * | 2019-01-21 | 2019-04-23 | 济南大学 | A kind of isolated neutral system fault line selection method for single-phase-to-ground fault |
| CN112436493A (en) * | 2020-11-26 | 2021-03-02 | 广东电网有限责任公司佛山供电局 | Single-phase earth fault centralized protection method of small-resistance earth system |
| CN112684288A (en) * | 2020-12-10 | 2021-04-20 | 国网陕西省电力公司西咸新区供电公司 | Method for realizing small-current single-phase grounding line selection by utilizing three-phase fault signal current |
| CN113258544A (en) * | 2021-04-13 | 2021-08-13 | 李景禄 | Compensation type intelligent resistance ground fault processing method |
Non-Patent Citations (1)
| Title |
|---|
| 基于联合电压判据的高压并联电容器单相接地故障保护方法;马伟东;《电力系统保护与控制》;第47卷(第22期);第142-147页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114089107A (en) | 2022-02-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107064741B (en) | A kind of successive ground fault line selecting method of distribution network line different name phase two o'clock | |
| Nayak et al. | Wide-area measurement-based backup protection for power network with series compensation | |
| Guzmán et al. | Transmission line protection system for increasing power system requirements | |
| Choudhary et al. | A review on microgrid protection | |
| CN112595930B (en) | Backup protection method for petal type urban power grid area containing distributed power supply | |
| CN110912093B (en) | Disconnection relay protection method for measuring matching of load side bus line voltage and spare power automatic switching | |
| Ohrstrom et al. | Fast protection of strong power systems with fault current limiters and PLL-aided fault detection | |
| US20150124358A1 (en) | Feeder power source providing open feeder detection for a network protector by shifted neutral | |
| CN114089107B (en) | Capacitor line selection method for single-phase grounding fault handling of transformer substation center point grounding | |
| CN110768206B (en) | Single-phase earth fault protection method for small-resistance earth system | |
| Lin et al. | Principles and implementations of hierarchical region defensive systems of power grid | |
| CN106469905B (en) | Distribution network protection method based on distribution network three-way defense line | |
| Ibrahim et al. | On the DC Microgrids Protection Challenges, Schemes, and Devices‐A Review | |
| Shilong et al. | Fault line selection of single phase grounding fault in small-current ground system based on reactive current | |
| CN100362718C (en) | Fault-tolerant complex judging self adaption high voltage parallel reactor turn-to-turn protection | |
| Srivastava et al. | Frequency and voltage data processing based feeder protection in medium voltage microgrid | |
| CN110912094B (en) | 3-66 kV line disconnection protection method for collecting bus line voltage at load end | |
| Ramos et al. | Analysis of short-circuit asymmetrical currents in power distribution systems | |
| Ratnadeep et al. | Fault level analysis of power distribution system | |
| Li et al. | A novel substation area backup protection for smart substation | |
| Tian et al. | Shunt capacitor bank protection in UHV pilot project | |
| Bin-Bin et al. | Research on an incorrect operation of grounding transformer protection and its improving measures | |
| CN115360683B (en) | Protection method for single-phase earth fault of neutral point ungrounded system | |
| CN103795043A (en) | Overload maloperation-proof transmission line phase-to-phase fault backup protection method | |
| Li et al. | Intelligent control technology of tripping and reclosing for double-circuit transmission line on the same tower |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |