CN202486278U - Power distribution network cable insulation detection system - Google Patents

Power distribution network cable insulation detection system Download PDF

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Publication number
CN202486278U
CN202486278U CN2012201393428U CN201220139342U CN202486278U CN 202486278 U CN202486278 U CN 202486278U CN 2012201393428 U CN2012201393428 U CN 2012201393428U CN 201220139342 U CN201220139342 U CN 201220139342U CN 202486278 U CN202486278 U CN 202486278U
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CN
China
Prior art keywords
power distribution
distribution network
insulation
cable
monitoring device
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Expired - Lifetime
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CN2012201393428U
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Chinese (zh)
Inventor
崔吉方
赵煜
郑增成
姜洪东
吕连举
杨洪灿
孙二双
王杰
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Qujing Power Supply Bureau Of Yunnan Power Grid Corp
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Qujing Power Supply Bureau Of Yunnan Power Grid Corp
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Priority to CN2012201393428U priority Critical patent/CN202486278U/en
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Abstract

Provided is a power distribution network cable insulation detection system. The power distribution network cable insulation detection system comprises a background computer system installed in a master control center and a low-current grounding line selection insulation monitoring device installed in a substation and a communication network which connects the background computer system and the low-current grounding line selection insulation monitoring device. The low-current grounding line selection insulation monitoring device is responsible for identifying and detecting high-frequency capacitance and current signals released when transient grounding fault happens to cable outlets in the substation, recording data and forming an oscillographic document, then transmitting information of the oscillographic document to the background monitoring computer system through Ethernet communication network for analysis and statistics, and therefore the data analysis on insulation state of power distribution network is achieved. Weekly statistics, monthly statistics and annual statistics of insulation monitoring reports, as well as Specific Operating Requirement (SOE) reports are generated automatically. The power distribution network cable insulation detection system can effectively screen faults on electric insulation of the power distribution network system in an early deterioration stage, give expert suggestions on wire repair, and therefore prevent faults before faults happen and effectively improve operational safety of the power distribution network system.

Description

A kind of power distribution network cable insulation detection system
Technical field
The utility model belongs to the electric power project engineering field, particularly a kind of power distribution network cable insulation detection system.
Background technology
Cable insulation material is after using certain time limit, and insulating property all can present deterioration to a certain degree, and this is called as " insulation ag(e)ing ".The reason that causes this cable generation deterioration is more, and deterioration that current weigherization, hot deterioration, chemical deterioration, mechanical deterioration even mouse insect pest cause etc. is arranged, but the main current weigherization that is still.Its main deterioration form is: 1. shelf depreciation current weigherization; 2. electric branch deterioration; 3. water tree degradation.Research shows that which kind of deterioration all possibly cause insulation resistance to descend, and capacitive earth current leaks phenomenons such as increase.Therefore the important parameter of these two amounts of insulation resistance and capacitive earth current Chang Zuowei line cord insulation quality can be measured cable insulation through the on-line monitoring of cable earth capacitance electric current for this reason, declares several insulation degradation degree.
At present, the on-line monitoring of high voltage power cable is carried out relatively early abroad, and many is Japan.As far back as early 1980s, multiple diagnostic techniquess such as DC component method, dc superposition method, dielectric loss method and low-frequency ac method of superposition are developed in just constantly research and the exploration in this field of Japan.SEI Corporation develops on-line operation cable monitoring appearance in the later stage eighties, is mainly used in 3~11kV isolated neutral or through the system of grounding through arc, employing be DC stacked law technology.
China's on-line monitoring of cable starting develops slow relatively than later.Early 1990s, Shanghai Electrical Cable Research Institute has also begun research work, and has carried out a large amount of site tests.1993, this institute adopted the compound diagnostic method of direct current composition method and dc superposition method, be developed into to be suitable for industry spot use cable diagnostic equipment, but result of use was undesirable.
Generally, ripe not enough for the on-line monitoring research of cable insulation both at home and abroad, for the whole bag of tricks of present research, they have following shortcoming:
(1) the DC component method is not suitable for electric system and uses because the interference of stray current and Weak current extract factors such as difficulty.
(2) dc superposition method is applicable to low-voltage cable insulating monitoring system, owing to can not solve the contradiction between earthing mode and the direct current signal loading, is not suitable for being applied to high-tension cable.This method needs the external dc signal, and it is big to implement difficulty.
(3) dielectric loss method can't reflect local cable insulation degradation degree, and its accuracy of detection is not high.
(4) low-frequency ac method of superposition need apply a 7.5Hz, 20V low-frequency voltage on conductor cable, implement inconvenient.
Along with the electric system capacity constantly enlarges, the constantly increase of the cost of high-tension cable and maintenance cost is studied a kind of economically feasible, safe and reliable on-line monitoring method and apparatus is an exigence.
The utility model content
The purpose of the utility model provides a kind of power distribution network cable insulation detection system, can effectively solve the early stage examination state of an illness of distribution network system electric insulation at degradation of insulation, provides the expert advice of line maintenance, effectively improves the distribution network system security of operation.
In order to realize above-mentioned purpose; The utility model technical scheme be: a kind of power distribution network cable insulation detection system; Form by transformer station's cable outlet, zero sequence current mutual inductor, bus-bar potential transformer, small current earthing wire-selecting insulating monitoring device, ethernet communication network and background computer system; Wherein, zero sequence current mutual inductor is installed on transformer station's cable outlet.Transformer station's cable outlet, zero sequence current mutual inductor and substation bus bar voltage transformer (VT) are the intrinsic equipment of transformer station.The signal of zero sequence current mutual inductor and the generation of substation bus bar voltage transformer (VT) is connected to through special-purpose umbilical cable on the signal sampling port of small current earthing wire-selecting insulating monitoring device, and the record ripple incident of discerning processing formation through small current earthing wire-selecting insulating monitoring device is sent to computer system through ethernet communication network and carries out the analytic statistics processing.
Said device is used to detect the method for power distribution network cable insulation, comprises the steps:
The high frequency capacitance current signal of releasing over the ground when zero sequence current mutual inductor is responsible for induction line generation instantaneity earth fault also is converted into rated current 1A output.
When circuit generation instantaneity earth fault, the bus-bar potential transformer open delta induces the residual voltage signal.
Small current earthing wire-selecting insulating monitoring device; Has the 51.2kHz High Speed Sampling System; Can accomplish weekly ripple 1024 points of sampling; The high frequency earthing signal that zero sequence current mutual inductor and voltage transformer (VT) open delta produce when being responsible for gathering cable outlet 1 generation instantaneity earth fault forms record ripple file, and information is sent to the background monitoring computer system of Master Control Center through ethernet communication network.The multipotency of the capacity of small current earthing wire-selecting insulating monitoring device detects 4 sections bus residual voltages and 38 telegram in reply cable outlet high frequency capacitance current signals.
Computer system receives the record ripple event signal that small current earthing wire-selecting insulating monitoring device sends, high frequency capacitance current signal time of origin, frequency, the overtone order of releasing over the ground during analysis circuit generation instantaneity earth fault; Just can generate an ordinate is overtone order, and horizontal ordinate is the curve of time, just can judge the degradation of this cable and the rule that sparks over the ground through shape, the tendency of analytic curve; Choose the instantaneous discharge event information according to record ripple file type, if the overtone order and the time that satisfy condition and then read this document, and on curve map, draw a bit; After having visited all message files, draw this point above curve out with connecting line, can analyze from this curve map; The instantaneous discharge accident frequency is high in certain time period; Overtone order changes little, and this variation is accompanied by putting off of time, has repeatability; Thereby judge the state of insulation of this circuit, be implemented in the early stage examination state of an illness of degradation of insulation.
The outstanding beneficial effect of the utility model is:
High frequency capacitance current signal time of origin, frequency, the overtone order of releasing over the ground in the time of 1, can analysis circuit generation instantaneity earth fault; Generating an ordinate is overtone order; Horizontal ordinate is the curve of time; Shape, tendency through analytic curve just can be judged the degradation of this cable and the rule that sparks over the ground, and generate the SOE incident.Remind the operations staff, be implemented in the early stage examination state of an illness of degradation of insulation, prevent trouble before it happens, improve system reliability and stability.
2, according to statistics, generate Zhou Tongji, month statistics, year statistics insulating monitoring report voluntarily, also exception reporting can be provided at any time as required, for the cable insulation situation provides the real-time online supervision.
Description of drawings
Fig. 1 is the structural representation of the pick-up unit of the described power distribution network cable insulation of the utility model.
Fig. 2 is the computer expert system analysis software process flow diagram of the utility model.
Fig. 3 is the overtone order change curve that computing machine is drawn according to instantaneous accident record ripple file.
Embodiment
Below in conjunction with accompanying drawing and embodiment the technical scheme of the utility model is further specified.
As shown in Figure 1; The described power distribution network cable insulation of the utility model detection system is made up of transformer station's cable outlet 1, zero sequence current mutual inductor 2, bus-bar potential transformer 3, small current earthing wire-selecting insulating monitoring device 4, ethernet communication network 5 and computer system 6.Wherein, zero sequence current mutual inductor 2 is installed on transformer station's cable outlet 1.Transformer station's cable outlet 1, zero sequence current mutual inductor 2 and substation bus bar voltage transformer (VT) 3 are the intrinsic component equipments of transformer station.Zero sequence current mutual inductor 2 is connected to through special-purpose umbilical cable on the signal sampling port of small current earthing wire-selecting insulating monitoring device 4 with the signal of substation bus bar voltage transformer (VT) 3 generations, and the record ripple incident that 4 identification processing form through small current earthing wire-selecting insulating monitoring device is sent to computer system 6 through ethernet communication network 5 and carries out the analytic statistics processing.
Said device is used to detect the method for power distribution network cable insulation, comprises the steps:
Transformer station's cable outlet 1 is installed the high frequency capacitance current signal of releasing over the ground when zero sequence current mutual inductor 2 is responsible for induction line generation instantaneity earth fault and is converted into rated current 1A output.
When circuit generation instantaneity earth fault, bus-bar potential transformer 3 open deltas induce the residual voltage signal.
Small current earthing wire-selecting insulating monitoring device 4; Has the 51.2kHz High Speed Sampling System; Can accomplish weekly ripple 1024 points of sampling; Zero sequence current mutual inductor 2 and the high frequency earthing signal that voltage transformer (VT) 3 open deltas produce when being responsible for gathering cable outlet 1 generation instantaneity earth fault form record ripple file, and information is sent to the background monitoring computer system 6 of Master Control Center through ethernet communication networks 5.The multipotency of the capacity of small current earthing wire-selecting insulating monitoring device 4 detects 4 sections bus residual voltages and 38 telegram in reply cable outlet high frequency capacitance current signals.
Computer system 6 receives the record ripple event signal that small current earthing wire-selecting insulating monitoring device 4 sends, high frequency capacitance current signal time of origin, frequency, the overtone order of releasing over the ground during analysis circuit generation instantaneity earth fault; Just can generate an ordinate is overtone order, and horizontal ordinate is the curve of time, just can judge the degradation of this cable and the rule that sparks over the ground through shape, the tendency of analytic curve; Choose the instantaneous discharge event information according to record ripple file type, if the overtone order and the time that satisfy condition and then read this document, and on curve map, draw a bit; After having visited all message files, draw this point above curve out with connecting line, can analyze from this curve map; The instantaneous discharge accident frequency is high in certain time period; Overtone order changes little, and this variation is accompanied by putting off of time, has repeatability; Thereby judge the state of insulation of this circuit, be implemented in the early stage examination state of an illness of degradation of insulation.Prevent trouble before it happens, improve system reliability and stability.
According to statistics, generate Zhou Tongji, month statistics, year statistics insulating monitoring report voluntarily simultaneously, also exception reporting can be provided at any time as required, for the distribution network system insulation status provides real-time online supervision and assessment.
Analyzing embodiment is realized by following step: gather the high frequency instantaneous discharge signal of cable line through small current earthing wire-selecting insulating monitoring device, and preserve signal for record ripple file, through initial, the concluding time of discharge of computer expert system analysis software high frequency instantaneous discharge signal; And analyzing is the signal of which bar circuit, and analysis result is presented in the fault harmonic wave variation diagram, as can be seen from Figure 3; Continuity along with service time; The instantaneous discharge number of times increases, and harmonic frequency is at gradually decline, the continuous deterioration process of insulation of this expression circuit; Answer interruption maintenance, produce to prevent more serious accident.
Fig. 2 provides the software analysis flow process:
Step 1: the system start-up of insulating monitoring expert system analysis software initialization, initialization system gets into step 2;
Step 2: set up correspondence with small current earthing wire-selecting insulating monitoring device, read data message wherein;
Step 3, step 4: whether the identification read data information instantaneity ground connection discharge information incident, if calling record ripple file automatically then, and document storage to designated directory, otherwise return step 2.
Step 5, step 6: according to the condition of user's input,, search corresponding record ripple file,, get into step 7 if record ripple file exists like Time To Event, line number etc.; Otherwise return step 3 again.
Step 7, step 8: open record ripple file and read overtone order and recorder data such as Time To Event; Read recorder data, carry out analytic statistics to data, generate fault harmonic wave variation diagram to final result;
Step 9: the result according to analysis obtains, analysis and suggestion is provided, guides user is accomplished Fault Processing.
Step 10: finish to analyze.

Claims (1)

1. power distribution network cable insulation detection system; It is characterized in that; This system is made up of transformer station's cable outlet, zero sequence current mutual inductor, bus-bar potential transformer, small current earthing wire-selecting insulating monitoring device, ethernet communication network and computer system; Wherein, Zero sequence current mutual inductor is installed on transformer station's cable outlet; Transformer station's cable outlet, zero sequence current mutual inductor and substation bus bar voltage transformer (VT) are the intrinsic component equipments of transformer station, and the signal of zero sequence current mutual inductor and the generation of substation bus bar voltage transformer (VT) is connected to through special-purpose umbilical cable on the signal sampling port of small current earthing wire-selecting insulating monitoring device, and the record ripple incident of discerning processing formation through small current earthing wire-selecting insulating monitoring device is sent to computer system through ethernet communication network and carries out the analytic statistics processing.
CN2012201393428U 2012-04-05 2012-04-05 Power distribution network cable insulation detection system Expired - Lifetime CN202486278U (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103869222A (en) * 2012-12-12 2014-06-18 山东电力集团公司济宁供电公司 Bus insulation state monitoring system and method
CN103954887A (en) * 2014-03-31 2014-07-30 国家电网公司 Power line insulation monitoring method based on instant fault
CN104764956A (en) * 2015-03-24 2015-07-08 深圳供电局有限公司 Method and system for detecting and optimizing insulation level of cable medium
CN105067983A (en) * 2015-09-16 2015-11-18 山东怡讯电气有限公司 Cable insulation data online acquisition and processing system
CN105676092A (en) * 2016-03-29 2016-06-15 中国石油大学(北京) Method and system for monitoring insulation level of substation power cable
WO2022068074A1 (en) * 2020-09-29 2022-04-07 山东大学 Early warning method and system for slowly developing permanent fault

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103869222A (en) * 2012-12-12 2014-06-18 山东电力集团公司济宁供电公司 Bus insulation state monitoring system and method
CN103954887A (en) * 2014-03-31 2014-07-30 国家电网公司 Power line insulation monitoring method based on instant fault
CN104764956A (en) * 2015-03-24 2015-07-08 深圳供电局有限公司 Method and system for detecting and optimizing insulation level of cable medium
CN105067983A (en) * 2015-09-16 2015-11-18 山东怡讯电气有限公司 Cable insulation data online acquisition and processing system
CN105067983B (en) * 2015-09-16 2018-01-16 山东怡讯电气有限公司 A kind of cable insulation online data acquisition processing system
CN105676092A (en) * 2016-03-29 2016-06-15 中国石油大学(北京) Method and system for monitoring insulation level of substation power cable
CN105676092B (en) * 2016-03-29 2018-11-16 中国石油大学(北京) Electric substation's power cable insulation level monitoring method and system
WO2022068074A1 (en) * 2020-09-29 2022-04-07 山东大学 Early warning method and system for slowly developing permanent fault

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