CN117269831A - Monitoring method for electric leakage of alternating current system loop for transformer substation - Google Patents
Monitoring method for electric leakage of alternating current system loop for transformer substation Download PDFInfo
- Publication number
- CN117269831A CN117269831A CN202311216662.8A CN202311216662A CN117269831A CN 117269831 A CN117269831 A CN 117269831A CN 202311216662 A CN202311216662 A CN 202311216662A CN 117269831 A CN117269831 A CN 117269831A
- Authority
- CN
- China
- Prior art keywords
- current
- head
- induced
- currents
- signals
- 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.)
- Pending
Links
- 238000012544 monitoring process Methods 0.000 title claims abstract description 28
- 238000000034 method Methods 0.000 title claims abstract description 12
- 230000006698 induction Effects 0.000 claims abstract description 21
- 230000004931 aggregating effect Effects 0.000 claims description 2
- 230000009466 transformation Effects 0.000 claims description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000001934 delay Effects 0.000 description 2
- 206010000369 Accident Diseases 0.000 description 1
- 125000003275 alpha amino acid group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012423 maintenance 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
The invention particularly relates to a method for monitoring leakage of an alternating current system loop for a transformer substation, which comprises the steps of respectively installing Residual Current Transformers (RCT) at the head end and the tail end of a radial branch of the alternating current system loop, installing N residual current transformers in the middle of the radial branch, and executing the following steps: naming all the residual current transformers, setting the current sensed by the head-end residual current transformer as head-end sensing current, and setting the currents sensed by other residual current transformers as other sensing currents; and then, superposing the head-end induction current and other induction currents to form square wave forming judging signals with two different frequencies, determining and adjusting the phase difference between the head-end induction current and the other induction currents according to the phase difference between the judging signals, and finally, aligning the adjusted other induction currents with the head-end induction current to obtain aligned induction currents, and carrying out AC system loop leakage monitoring for the transformer substation through the aligned induction currents.
Description
Technical Field
The invention particularly relates to a monitoring method for loop leakage of an alternating current system for a transformer substation, and belongs to the technical field of loop on-line monitoring.
Background
The electric fire accident of the transformer substation is the focus of operation and maintenance work of the transformer substation. The electric fire in the station is generally classified into a fire caused by short circuit of a radial cable and insulation damage of the radial cable, wherein the short circuit current is larger, and the fault current can be cut off through actions of an air switch, a fuse and a protection device. The latter generally has a small fault current, which is often found in the event of an electric shock or fire, which is a great fire fighting pressure for substation ac systems having a large number of radial cable loops. Therefore, it is important to monitor whether the transformer substation alternating current system loop leaks or not in real time, in the prior art, a residual current method is mostly adopted for monitoring, namely, residual Current Transformers (RCT) are installed at the first end and the last end of a radial branch of the transformer substation alternating current system loop to monitor induction circuits at the two ends of the radial branch in real time, and leakage judgment is performed by calculating the sum of induction currents at the two ends, so that whether the transformer substation alternating current system loop leaks or not is monitored in real time. In the prior art, as the residual current transformers are only arranged at the first end and the last end of the radial branch, if other ports are arranged in the middle of the radial branch and current is fed out, the sum of the induction currents collected at the first end and the last end of the radial branch can not represent the leakage condition of the whole transformer substation alternating current system loop, and the false alarm condition occurs; meanwhile, the transformer substation alternating current system is difficult to access into the time synchronization system, and additional errors are caused by phase differences of currents at the first end and the last end of the radial branch due to factors such as communication delay, so that misinformation is caused by inaccurate sum of induced currents at the two ends of the radial branch.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: how to accurately monitor the loop leakage of the transformer substation alternating current system in real time.
The technical scheme provided by the invention is as follows: a monitoring method of electric leakage of an alternating current system loop for a transformer substation comprises the steps of respectively installing Residual Current Transformers (RCT) at the head end and the tail end of a radial branch of the alternating current system loop, installing N residual current transformers in the middle of the radial branch, and executing the following steps:
step 1: the residual current transformer at the head end of the radial branch is named RCTS, and the current induced by the RCTS is named head-end induced current; the residual current transformers at the tail ends of the radial branches are named as RCTM, and the N residual current transformers in the middle of the radial branches are named sequentially according to the sequence from RCT1 to RCTN; setting the current induced by all the residual current transformers except the RCTS as other induced currents;
step 2: the head-end current information and the two frequencies are respectivelyAnd->The square wave signals of (2) are simultaneously superimposed to form a head end judgment signal +.>All other induced currents are sequentially and respectively +.>And->The square wave signals of the (a) are simultaneously overlapped to form other judging signals, and the other judging signals are collected to form other judging signal sets I pd As shown in the following formula (1),
in the formula (1), the components are as follows,is the other judgment signal formed by the RCTM; />Is the other judgment signal formed by the RCT 1; />Is the other judgment signal formed by the RCTN;
aggregating the other judgment signals I pd All other judgment signals in the network are sequentially connected with the head end judgment signalComparing to obtain the other judging signals and the reference judging signal +.>The phase difference is the phase difference between other induced currents represented by the other judging signals and the head-end induced current, and the phase difference between the other induced currents and the head-end current is adjusted within a period T of the head-end current through sine function transformation;
step 3: setting the period T of the head-end current as a monitoring period for monitoring the leakage of the loop of the transformer substation alternating current system, wherein in the process of monitoring the leakage of the loop of the transformer substation alternating current system, a peak value appears according to the reference current in the monitoring periodPhase of time->Obtaining alignment induction currents of all residual current transformers except the RCTS, and collecting all alignment induction currents to form an alignment induction current set +.>As shown in the following formula (1),
in the formula (1), the components are as follows,is the alignment induced current value of the RCTM; />Is an alignment induced current value of the RCT 1; />Is the alignment induced current value of the RCTN;
the current vector differential I of the radial branch is obtained by calculation of the following formula (2) E ，
When the current vector is differential I E If the following (3) is satisfied, the current monitoring period is regarded as a dangerous period
I E ＞I T (3)，
In the formula (3), I T The leakage experience critical value is selected according to the historical accident data;
and when A dangerous periods continuously occur, A is a historical experience value, and the loop of the transformer substation alternating current system is considered to have electric leakage, and a warning is sent out.
The beneficial effects of the invention are as follows: 1. according to the invention, two kinds of square wave signals with different frequencies are superimposed on the basis of current information sensed by the residual current transformer to form a brand-new composite judgment signal, so that the phase difference between other sensed currents and the head-end sensed current can be found, and meanwhile, the problem of integer number of cycle delays can be solved, and because the sensed current is a sine function wave, delay exceeding one period is difficult to see on a function image, and by superimposing square waves with different frequencies, a brand-new composite judgment signal is formed, so that whether the phase difference exceeds the integer number of cycle delays can be seen; 2. the invention adopts special current vector differential judgment to monitor each monitoring period in real time, and simultaneously adopts a plurality of continuous monitoring periods to meet the current vector differential judgment to consider that the leakage occurs, thereby avoiding the accident.
Detailed Description
The method for monitoring the leakage of the AC system loop for the transformer substation is further described by combining the specific embodiment
The invention relates to a method for monitoring leakage of an alternating current system loop for a transformer substation, which is characterized in that Residual Current Transformers (RCT) are respectively arranged at the head end and the tail end of a radial branch of the alternating current system loop, two residual current transformers are further arranged in the middle of the radial branch, and the following steps are executed:
step 1: the residual current transformer at the head end of the radial branch is named RCTS, and the current induced by the RCTS is named head-end induced current; the residual current transformers at the tail ends of the radial branches are named as RCTM, and the two residual current transformers in the middle of the radial branches are named as RCT1 and RCT2 respectively; the currents induced by RCTM, RCT1 and RCT2 are defined as other induced currents.
Step 2: simultaneously superposing the head-end induction current induced by RCTS and two square wave signals with the frequencies of 20Hz and 70Hz respectively to form a head-end judging signalOther induced currents induced by RCTM, RCT1 and RCT2 are sequentially overlapped with two square wave signals with the frequencies of 20Hz and 70Hz respectively at the same time to formForming other judging signals, and collecting the other judging signals to form other judging signal sets I pd As shown in the following formula (1),
in the formula (1), the components are as follows,is other judgment signals formed by the RCTM; />Other judgment signals formed by RCT 1; />Other judgment signals formed by RCT2;
head end judgment signal formed by RCTMOther judgment signals formed by RCT1 +.>And RCT2, and the other judgment signal +.>Judging signals of head end in turn>Comparing to obtain all other judging signals and head end judging signals>Phase difference delta between them, other judgment signal formed by RCTM at this time +.>And head end judgment signal->Phase difference between->Namely, the phase difference between the other induced current induced by RCTM and the head-end induced current is +.>Similarly, the other judgment signal formed by RCT1 +.>And head end judgment signal->Phase difference betweenNamely, the phase difference between the other induced currents induced by RCT1 and the head-end induced current is ∈>Other judgment signals formed by RCT2 +.>And head end judgment signal->Phase difference between->Namely, the phase difference between the other induced current induced by RCT2 and the head-end induced current is ∈> 375 °, ->85 DEG,>is 675 °; due to->And->Are all larger than 360 DEG of one period of the head-end induced current, so +.>And->Adjusted to within 360 ° of one cycle.
Step 3: the period of setting the reference current is 20ms which is a monitoring period for monitoring the leakage of the primary transformer substation alternating current system loop, and in the process of monitoring the leakage of the primary transformer substation alternating current system loop, the peak value of the reference current appears according to the monitoring periodPhase of time->Obtaining alignment induction currents of all residual current transformers except RCTS, and collecting all alignment induction currents to form an alignment induction current set +.>As shown in the following formula (1),
in the formula (2), the amino acid sequence of the compound,is the alignment induced current value of RCTM; />Is the alignment induced current value of RCT 1;is the alignment induced current value of RCTN;
the current vector differential I of the radial branch is obtained by calculation of the following formula (3) E ，
When the current vector is differential I E If the following (4) is satisfied, the current monitoring period T is regarded as a dangerous period
I E ＞I T (4)，
In the formula (4), I T Is a leakage experience critical value selected according to experience;
when 750 dangerous periods appear continuously, the circuit of the transformer substation alternating current system is considered to have electric leakage, and a warning is sent out.
Claims (1)
1. A monitoring method of electric leakage of an alternating current system loop for a transformer substation is characterized by comprising the following steps: residual Current Transformers (RCT) are respectively arranged at the head end and the tail end of a radial branch of the alternating current system loop, N residual current transformers are respectively arranged in the middle of the radial branch, and the following steps are executed:
step 1: the residual current transformer at the head end of the radial branch is named RCTS, and the current induced by the RCTS is named head-end induced current; the residual current transformers at the tail ends of the radial branches are named as RCTM, and the N residual current transformers in the middle of the radial branches are named sequentially according to the sequence from RCT1 to RCTN; setting the current induced by all the residual current transformers except the RCTS as other induced currents;
step 2: the head-end current information and the two frequencies are respectivelyAnd->The square wave signals of (2) are simultaneously superimposed to form a head end judgment signal +.>All other induced currents are sequentially and respectively +.>And->The square wave signals of the (a) are simultaneously overlapped to form other judging signals, and the other judging signals are collected to form other judging signal sets I pd As shown in the following formula (1),
in the formula (1), the components are as follows,is the other judgment signal formed by the RCTM; />Is the other judgment signal formed by the RCT 1; />Is formed by the RCTNOther judgment signals;
aggregating the other judgment signals I pd All other judgment signals in the network are sequentially connected with the head end judgment signalComparing to obtain the other judging signals and the reference judging signal +.>The phase difference is the phase difference between other induced currents represented by the other judging signals and the head-end induced current, and the phase difference between the other induced currents and the head-end current is adjusted within a period T of the head-end current through sine function transformation;
step 3: setting the period T of the head-end current as a monitoring period for monitoring the leakage of the loop of the transformer substation alternating current system, wherein in the process of monitoring the leakage of the loop of the transformer substation alternating current system, a peak value appears according to the reference current in the monitoring periodPhase of time->Obtaining alignment induction currents of all residual current transformers except the RCTS, and collecting all alignment induction currents to form an alignment induction current set +.>As shown in the following formula (1),
in the formula (1), the components are as follows,is the alignment induced current value of the RCTM; />Is an alignment induced current value of the RCT 1;is the alignment induced current value of the RCTN;
the current vector differential I of the radial branch is obtained by calculation of the following formula (2) E ，
When the current vector is differential I E If the following (3) is satisfied, the current monitoring period is regarded as a dangerous period
I E ＞I T (3)，
In the formula (3), I T The leakage experience critical value is selected according to the historical accident data;
and when A dangerous periods continuously occur, A is a historical experience value, and the loop of the transformer substation alternating current system is considered to have electric leakage, and a warning is sent out.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311216662.8A CN117269831A (en) | 2023-09-20 | 2023-09-20 | Monitoring method for electric leakage of alternating current system loop for transformer substation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311216662.8A CN117269831A (en) | 2023-09-20 | 2023-09-20 | Monitoring method for electric leakage of alternating current system loop for transformer substation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117269831A true CN117269831A (en) | 2023-12-22 |
Family
ID=89215473
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311216662.8A Pending CN117269831A (en) | 2023-09-20 | 2023-09-20 | Monitoring method for electric leakage of alternating current system loop for transformer substation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117269831A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109324257A (en) * | 2018-09-07 | 2019-02-12 | 国网浙江慈溪市供电有限公司 | Residual current on-Line Monitor Device |
| CN112710931A (en) * | 2020-12-16 | 2021-04-27 | 国网江苏省电力有限公司检修分公司 | Method and system for detecting earth leakage current of secondary side long-distance cable pair of alternating current system |
| CN113725813A (en) * | 2021-08-27 | 2021-11-30 | 杭州海兴电力科技股份有限公司 | Leakage protection method, device and equipment and leakage protection electric energy meter |
| CN114720906A (en) * | 2022-03-25 | 2022-07-08 | 国网江苏省电力有限公司超高压分公司 | Low-channel-dependence leakage current monitoring method for long cable of transformer station |
-
2023
- 2023-09-20 CN CN202311216662.8A patent/CN117269831A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109324257A (en) * | 2018-09-07 | 2019-02-12 | 国网浙江慈溪市供电有限公司 | Residual current on-Line Monitor Device |
| CN112710931A (en) * | 2020-12-16 | 2021-04-27 | 国网江苏省电力有限公司检修分公司 | Method and system for detecting earth leakage current of secondary side long-distance cable pair of alternating current system |
| CN113725813A (en) * | 2021-08-27 | 2021-11-30 | 杭州海兴电力科技股份有限公司 | Leakage protection method, device and equipment and leakage protection electric energy meter |
| CN114720906A (en) * | 2022-03-25 | 2022-07-08 | 国网江苏省电力有限公司超高压分公司 | Low-channel-dependence leakage current monitoring method for long cable of transformer station |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10910826B2 (en) | Voltage derivative and zero-sequence broken conductor detection | |
| US8174268B2 (en) | Protective relay monitoring system and method of comparing behavior patterns | |
| CN101943737B (en) | Single-phase earth fault diagnosis method and device | |
| WO2007048045A2 (en) | System and method for detecting power system conditions | |
| CN102420420A (en) | Single-phase grounding protection method and system | |
| CN103454549B (en) | A kind of looped network distribution system short trouble early detection, identification and routing method | |
| US20110254557A1 (en) | Electromechanical relays including embedded sensors | |
| CN110297154A (en) | Earth fault line selection method and device based on zero mould current temporary state energy | |
| CN103580009A (en) | Self-adaptive overload recognition system based on composite phasor plane and method thereof | |
| WO2021071734A1 (en) | Primary and system protection for an electric power delivery system | |
| CN112540259A (en) | Distribution network disconnection fault identification method and system suitable for intelligent power distribution terminal | |
| CN106505533A (en) | A kind of distance protection system and its control method suitable for half-wave power transmission circuit | |
| CN109888729A (en) | A kind of early warning type transformer protection method and device | |
| CN106569096B (en) | Online positioning method for single-phase fault of power distribution network | |
| CN108490369B (en) | HVDC transmission system inverter fast fault locating method | |
| CN102540015B (en) | Single-phase earthing of small current earthing system distance-finding method and distance measuring equipment | |
| CN117269831A (en) | Monitoring method for electric leakage of alternating current system loop for transformer substation | |
| CN103809078B (en) | The single-phase permanent fault recognition methods of a kind of both-end band shunt reactor transmission line of electricity | |
| CN108051693A (en) | A kind of method of the raising earth fault judgment accuracy based on TAS devices | |
| CN114814465B (en) | Distribution line fault finding system and method | |
| EP3874572A1 (en) | Accelerated zone-2 protection for transmission lines | |
| CN114720906A (en) | Low-channel-dependence leakage current monitoring method for long cable of transformer station | |
| CN101726674B (en) | Method for on-line assessment of insulation on-line monitoring system of substation | |
| CN112710931B (en) | Method and system for detecting earth leakage current of secondary side long-distance cable pair of alternating current system | |
| CN111880035B (en) | Power distribution network fault monitoring system and method based on multi-source measurement data |
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 |