CN108037423A - A kind of high-voltage cable insulating on-Line Monitor Device and method based on double differential CT methods - Google Patents
A kind of high-voltage cable insulating on-Line Monitor Device and method based on double differential CT methods Download PDFInfo
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- CN108037423A CN108037423A CN201711303073.8A CN201711303073A CN108037423A CN 108037423 A CN108037423 A CN 108037423A CN 201711303073 A CN201711303073 A CN 201711303073A CN 108037423 A CN108037423 A CN 108037423A
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- 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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- 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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/14—Circuits therefor, e.g. for generating test voltages, sensing circuits
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- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The present invention a kind of high-voltage cable insulating on-Line Monitor Device and method based on double differential CT methods, including 6 straight-through current transformers, active power filtering amplifier, Zigbee wireless communication modules and computer；6 straight-through current transformers are used to obtain cable circuit head/end A, B, C three-phase current differential waves；The active power filtering amplifier is used to after filtering collection signal amplify, and is transmitted to Zigbee wireless communication modules；The Zigbee wireless communication modules are used to receive current differential signal, and are transmitted to computer；The computer is used to store first and last end A, B, C three-phase current differential wave and calculate secondary differential values, then judges cable run insulation status.The present invention realizes the on-line monitoring that ac high-voltage cable road is insulated in the case of load is asymmetric.
Description
Technical field
The present invention relates to high-voltage cable insulating to monitor field, more particularly to a kind of high-voltage electricity based on double differential CT methods on-line
Cable insulation line monitoring device and method.
Background technology
With the raising of working voltage grade in power grid, high voltage power cable is largely laid in operation of power networks.With electricity
The raising of cable working voltage grade, requires to be continuously improved, the thing followed is for cable running safety to insulating performance of cable
The worry of problem.
What is be widely used at present in electric system is still the method for periodical power failure preventive trial, the method belong to from
Line detects.Work well to the cable detection for having not been put to operation, but since this method needs the detection that has a power failure, can not detect just
Cable in operation.Power failure can be caused by carrying out periodical power failure preventive trial, and the good cable of original insulation status exists
Insulation ag(e)ing even punctures after experiment repeatedly.
Therefore the operation conditions of cable is monitored on-line and diagnosis becomes extremely necessary, prediction in time and discovery cable
Possible failure, it has also become ensure the necessary ways of electric system cable run safe operation.Direct current in on-line monitoring method
Component method is not suitable for the cable to put into operation initial stage at present, stands good to the cable for running the long period.DC superposition method, low frequency
The addition method and AC superimposition method due in high-tension line three-phase neutral point be typically to be directly grounded, can not be folded on cable core
Add direct current, AC power, so not being suitable for high voltage XLPE cable insulated on-line monitoring.Domestic and international experts and scholars and world electricity
The best approach that partial discharge test is evaluated as XLPE insulated power cables insulation status is unanimously recommended by power authoritative organization.But
The local discharge signal of cable is faint, waveform is complicated and changeable is difficult to differentiate between, therefore the on-line monitoring at scene is difficult to realize in engineering.
Tan δ methods take out voltage signal from voltage transformer, and the power current for flowing through cable insulation, measurement are obtained from current transformer
The two phase difference value, so as to obtain tan δ., should but the relative error of voltage transformer may be more than the relative error of tan δ
Method is difficult to put into onsite application.Earth current method can be used to judge cable insulation state, but in the case where metal sheath is cross interconnected
Electric current on connecting wires is almost nil, and is easily disturbed by live noise signal, and above-mentioned on-line monitoring method does not consider cable end
Influence of the end load change to monitoring result, it is larger in high-voltage cable three-phase laod unbalance error.
The content of the invention
The purpose of the present invention is to solve high-voltage cable insulating on-line monitoring technique under the conditions of threephase load imbalance to ask
Topic, there is provided a kind of high-voltage cable insulating on-Line Monitor Device and method based on double differential CT methods.
The present invention is realized using following device：
A kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods, including 6 straight-through current transformers,
Active power filtering amplifier, Zigbee wireless communication modules and computer；
6 straight-through current transformers are used to obtain cable circuit head/end A, B, C three-phase current differential waves；
In 6 straight-through current transformers, the first straight-through current transformer, the second straight-through current transformer and the 3rd wear
Core type current transformer is separately mounted to cable run head end A, B, C threephase cable terminal bottom；First centre path current mutual inductance
The secondary coil of device, the second straight-through current transformer and the 3rd straight-through current transformer is connected using series system,
Gather cable run head end A, B, C three-phase current differential wave；4th straight-through current transformer, the 5th centre path current mutual inductance
Device and the 6th straight-through current transformer are separately mounted to cable run end A, B, C threephase cable terminals bottom；4th wears
The secondary coil of core type current transformer, the 5th straight-through current transformer and the 6th straight-through current transformer is using series connection
Mode is connected, and gathers cable run end A, B, C three-phase current differential wave；The current transformer is open-close type current
Mutual inductor, shell are insulated using unsaturated-resin；
The active power filtering amplifier is used to after filtering collection signal amplify, and is transmitted to Zigbee wireless communications
Module；
The Zigbee wireless communication modules are used to receive current differential signal, and are transmitted to computer；The computer
For storing first and last end A, B, C three-phase current differential wave and calculating secondary differential values, cable run insulation status is then judged.
Further, the A, B, C three-phase current differential waves, including differential values between A, B, C three-phase current and
The sum of A, B, C three-phase current it is differential.
Further, the A, B, C three-phase currents differential wave are differential and phase is differential forms by the amplitude of current signal.
Further, the rated power of 6 straight-through current transformers is 5W, no-load voltage ratio 200/5, installed in electric current
6 sampling resistors of mutual inductor secondary side are the accurate noninductive resistance of 0.2 Ω.
Further, collection cable run head end A, B, C the three-phase current differential wave or collection cable run head end
The method of A, B, C three-phase current differential wave is specially：Three sampling resistors of head and end are connected respectively, A, B, C three-phase currents
Signal phasor is added, and is obtained after sampled ohmically I/V conversions.
Further, the active power filtering amplifier is powered using solar cell and/or super capacitor；The Zigbee
Wireless communication module includes microcontroller, RF transceivers and SPI interface；The RF transceivers are CC2420 radio frequency chips, work
Frequency 2.4GHz, message transmission rate 250kb/s；Pass through SPI interface and MSP430F149 single chip communications；In the computer
First and last current signal is calculated with LABVIEW software analysis to change, and extracts characteristic signal, cable insulation is judged and is sent pre-
It is alert.
The present invention can take following method to realize：
A kind of high-voltage cable insulating on-line monitoring method based on double differential CT methods, including：
Step a, A, B, C threephase cables head end electric current and end current are gathered respectively using current transformer and calculate A, B,
The sum of C threephase cable head end electric currents and the sum of A, B, C threephase cable end current；By current signal through active power filtering amplifier
Host computer is sent a signal to by Zigbee wireless communication modules after filter and amplification；
Step b, the differential values and the sum of three-phase current between cable end piece A, B, C three-phase current are calculated in host computer
Differential values, judge that end load changes；
Step c, while the differential of the differential values between cable head A, B, C three-phase current and the sum of three-phase current is calculated
Value, judges the asymmetric degree of load and cable leakage current；
Step d, the differential values of the sum of head end electric current are subtracted to the differential values of the sum of threephase cable end three-phase current again, obtained
To the sum of three-phase current secondary differential values as the sum of threephase cable leakage current；By head end A, B, between C three-phase currents
Differential values subtract end A, B, and the differential values between C three-phase currents, obtain the secondary differential values between three-phase current as three-phase
The difference of cable leakage current；
Step e, judge whether phase and the setting insulation ag(e)ing early warning value of the sum of three-phase current secondary differential values are consistent, if
Step f is turned to when inconsistent, step g is turned to when consistent；
Step f, the phase of secondary differential values between three-phase current and setting insulation ag(e)ing early warning value are compared, and judged
Each phase cable insulation aging character；
Step g, generation on-line monitoring report, including end A, B, the differential values between C three-phase currents；Head end A, B, C tri-
Differential values between phase current；Secondary differential values between A, B, C three-phase current；The sum of end A's, B, C three-phase currents is differential
Value；The differential values of the sum of head end A, B, C three-phase current；The secondary differential values and cable run of the sum of A, B, C three-phase current are exhausted
Edge analysis result.
Further, the rated power of the current transformer is 5W, no-load voltage ratio 200/5, installed in current transformer two
6 sampling resistors of secondary side are the accurate noninductive resistance of 0.2 Ω.
Further, the collection A, B, C threephase cables head end electric current are specially with end current method：Head and end three
A sampling resistor is connected respectively, A, B, C three-phase current signal vector additions, is obtained after sampled ohmically I/V conversions.
Further, the active power filtering amplifier is powered using solar cell and super capacitor；The Zigbee without
Line communication module includes microcontroller, RF transceivers and SPI interface；The RF transceivers are CC2420 radio frequency chips, work frequency
Rate 2.4GHz, message transmission rate 250kb/s；Pass through SPI interface and MSP430F149 single chip communications；Used in the host computer
LABVIEW software analysis calculates the change of first and last current signal, extracts characteristic signal, cable insulation is judged and is sent pre-
It is alert.
The present invention has following good effect：The present invention provides a kind of high-voltage cable insulating based on double differential CT methods and supervises online
Device and method is surveyed, is extracted the differential wave of head end electric current and the differential wave of end current after cable run insulation ag(e)ing,
Compared with existing cable on-line monitoring technique, can reflect cable end piece load change, while head and end differential wave it
The enough influences for effectively avoiding end load change to on-line monitoring result of second difference kinetic energy that difference is formed, accurately reflect a variety of cables
Line insulation aging conditions.
Brief description of the drawings
Fig. 1 is a kind of high-voltage cable insulating on-line monitoring system embodiment flow chart based on double differential CT methods；
Fig. 2 is a kind of high-voltage cable insulating on-line monitoring method embodiment flow chart based on double differential CT methods；
Fig. 3 is signal acquisition mode on cable termination current transformer；
Fig. 4 is a kind of high-voltage cable insulating on-Line Monitor Device structure diagram based on double differential CT methods；
Embodiment
The present invention gives a kind of high-voltage cable insulating on-Line Monitor Device and embodiment of the method based on double differential CT methods,
In order to make those skilled in the art more fully understand the technical solution in the embodiment of the present invention, and make the above-mentioned mesh of the present invention
, feature and advantage can be more obvious understandable, further details of theory is made to technical solution in the present invention below in conjunction with the accompanying drawings
It is bright：
Preferred a kind of high-voltage cable insulating on-Line Monitor Device embodiment based on double differential CT methods of offer of the invention, such as schemes
Shown in 1：Including 6 straight-through current transformers 10, active power filtering amplifier 20, Zigbee wireless communication modules 30 and calculate
Machine 40；
6 straight-through current transformers 10 are used to obtain cable circuit head/end A, B, the differential letter of C three-phase currents
Number；In 6 straight-through current transformers, the first straight-through current transformer, the second straight-through current transformer and
Three straight-through current transformers are separately mounted to cable run head end A, B, C threephase cable terminal bottom；First centre path current
The secondary coil of mutual inductor 101, the second straight-through current transformer 102 and the 3rd straight-through current transformer 103 is using string
Connection mode is connected, and gathers cable run head end A, B, C three-phase current differential wave；4th straight-through current transformer 104,
Five straight-through current transformers 105 and the 6th straight-through current transformer 106 are separately mounted to cable run end A, B, C tri-
Phase cable termination bottom；4th straight-through current transformer, the 5th straight-through current transformer and the 6th centre path current are mutual
The secondary coil of sensor is connected using series system, gathers cable run end A, B, C three-phase current differential wave；The electricity
Current transformer is open-close type current transformer, and shell is insulated using unsaturated-resin；
The active power filtering amplifier 20 is used to after filtering collection signal amplify, and is transmitted to Zigbee channel radios
Believe module 30；
The Zigbee wireless communication modules 30 are used to receive current differential signal, and are transmitted to computer 40；The meter
Calculation machine is used to store first and last end A, B, C three-phase current differential wave and calculate secondary differential values, then judges that cable run insulate
Situation.
Preferably, the A, B, C three-phase current differential waves, including differential values and A between A, B, C three-phase current,
The sum of B, C three-phase current it is differential.
Preferably, the A, B, C three-phase currents differential wave are differential and phase is differential forms by the amplitude of current signal.
Preferably, the rated power of 6 straight-through current transformers is 5W, and no-load voltage ratio 200/5 is mutual installed in electric current
6 sampling resistors of sensor secondary side are the accurate noninductive resistance of 0.2 Ω.
Preferably, collection cable run head end A, B, C the three-phase current differential wave or collection cable run head end A,
The method of B, C three-phase current differential wave is specially：Three sampling resistors of head and end are connected respectively, A, B, C three-phase currents letter
Number vector addition, obtains after sampled ohmically I/V conversions.
Preferably, the active power filtering amplifier is powered using solar cell and/or super capacitor；The Zigbee without
Line communication module includes microcontroller, RF transceivers and SPI interface；The RF transceivers are CC2420 radio frequency chips, work frequency
Rate 2.4GHz, message transmission rate 250kb/s；Pass through SPI interface and MSP430F149 single chip communications；Used in the computer
LABVIEW software analysis calculates the change of first and last current signal, extracts characteristic signal, cable insulation is judged and is sent pre-
It is alert.
The present invention also provides a kind of embodiment of the method, as shown in Figure 2：
A kind of high-voltage cable insulating on-line monitoring method based on double differential CT methods, including：
S201, step a, gather A using current transformer respectively, B, and C threephase cables head end electric current and end current are simultaneously counted
Calculate the sum of the sum of A, B, C threephase cable head end electric currents and A, B, C threephase cable end current；By current signal through active power filtering
Host computer is sent a signal to by Zigbee wireless communication modules after amplifier filter and amplification；
S202, step b, differential values and three-phase current in host computer between calculating cable end piece A, B, C three-phase current
The sum of differential values, judge end load change；
S203, step c while calculate the differential values between cable head A, B, C three-phase current and the sum of three-phase current
Differential values, judge the asymmetric degree of load and cable leakage current；
Wherein step S202 and S203 can be exchanged；Have no effect on implementation result；
S204, step d, subtract the differential of the sum of threephase cable end three-phase current by the differential values of the sum of head end electric current again
Value, obtains the secondary differential values of the sum of three-phase current as the sum of threephase cable leakage current；By head end A, B, C three-phase currents it
Between differential values subtract end A, B, the differential values between C three-phase currents, obtain the secondary differential values conduct between three-phase current
The difference of threephase cable leakage current；
S205, step e, judge the secondary differential values of the sum of three-phase current phase and setting insulation ag(e)ing early warning value whether one
Cause, if turning to step (6) when inconsistent, step (7) is turned to when consistent；
S206, step f, by the phase of secondary differential values between three-phase current and setting insulation ag(e)ing early warning value compare,
And judge each phase cable insulation aging character；
S207, step g, generate and monitor report on-line, including end A, B, the differential values between C three-phase currents；Head end A,
Differential values between B, C three-phase current；Secondary differential values between A, B, C three-phase current；The sum of end A's, B, C three-phase currents
Differential values；The differential values of the sum of head end A, B, C three-phase current；The secondary differential values and cable of the sum of A, B, C three-phase current
Road insulation analysis result.
Preferably, the rated power of the current transformer is 5W, no-load voltage ratio 200/5, installed in Current Transformer Secondary
6 sampling resistors of side are the accurate noninductive resistance of 0.2 Ω, wherein, working frequency 2.4GHz, message transmission rate 250kb/
s；
Preferably, the collection A, B, C threephase cables head end electric current are specially as shown in Figure 3 with end current method：It is first
Last three sampling resistors in both ends are connected respectively, A, B, C three-phase current signal vector additions, after sampled ohmically I/V conversions
Obtain.
Preferably, the active power filtering amplifier is powered using solar cell and super capacitor；
Wherein, solar cell maintains active power filtering amplifier routine work, and super capacitor can ensure that on-line monitoring is set
Do not powered off in the standby short time under special circumstances.
The Zigbee wireless communication modules include microcontroller, RF transceivers and SPI interface；The RF transceivers are
CC2420 radio frequency chips, working frequency 2.4GHz, message transmission rate 250kb/s；Pass through SPI interface and MSP430F149 monolithics
Machine communicates；First and last current signal is calculated with LABVIEW software analysis to change, characteristic signal is extracted, to cable in the host computer
Insulation judges and sends early warning.
Wherein, single-phase or two-phase cable line insulation aging is may determine that when meeting following characteristic signal, sends early warning.
During the aging at the same time of threephase cable line insulation, the degree of aging between different phases is different, leakage current phase angle with
Change, i.e., the phase of secondary differential values changes therewith between three-phase current.Each phase leakage current phase is represented,Represent original
First two-phase release current and phase difference,New two-phase release current and phase difference is represented, i=A, B, C, establish phase difference matrixAfter aging, leakage current phase difference matrix is changed intoIt is alternate
Differential factorEstablish alternate differential matrixWhen unaged, kij=0, aging
It is more serious, kijIt is bigger, according to alternate differential matrix [kij] change judge each phase insulation ag(e)ing situation.
To sum up, the present invention provides a kind of high-voltage cable insulating on-Line Monitor Device and method based on double differential CT methods, bag
Include 6 straight-through current transformers, active power filtering amplifier, Zigbee wireless communication modules and computer；
6 straight-through current transformers are used to obtain cable circuit head/end A, B, C three-phase current differential waves；
In 6 straight-through current transformers, the first straight-through current transformer, the second straight-through current transformer and the 3rd wear
Core type current transformer is separately mounted to cable run head end A, B, C threephase cable terminal bottom；First centre path current mutual inductance
The secondary coil of device, the second straight-through current transformer and the 3rd straight-through current transformer is connected using series system,
Gather cable run head end A, B, C three-phase current differential wave；4th straight-through current transformer, the 5th centre path current mutual inductance
Device and the 6th straight-through current transformer are separately mounted to cable run end A, B, C threephase cable terminals bottom；4th wears
The secondary coil of core type current transformer, the 5th straight-through current transformer and the 6th straight-through current transformer is using series connection
Mode is connected, and gathers cable run end A, B, C three-phase current differential wave；The current transformer is open-close type current
Mutual inductor, shell are insulated using unsaturated-resin；
The differential wave of head end electric current and end after cable run insulation ag(e)ing can be extracted by the apparatus above present invention
The differential wave of electric current, compared with existing cable on-line monitoring technique, can reflect the change of cable end piece load, while first and last
The enough influences for effectively avoiding end load change to on-line monitoring result of second difference kinetic energy that the difference of both ends differential wave is formed, it is accurate
Really reflect a variety of cable run insulation ag(e)ing situations.
Above example is to illustrative and not limiting technical scheme.Appointing for spirit and scope of the invention is not departed from
What modification or local replacement, should all cover among scope of the presently claimed invention.
Claims (10)
1. a kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods, it is characterised in that including 6 punching electricity
Current transformer, active power filtering amplifier, Zigbee wireless communication modules and computer；
6 straight-through current transformers are used to obtain cable run head/end A, B, C three-phase current differential waves；Described 6
In a straight-through current transformer, the first straight-through current transformer, the second straight-through current transformer and the 3rd punching
Current transformer is separately mounted to cable run head end A, B, C threephase cable terminal bottom；First straight-through current transformer,
The secondary coil of two straight-through current transformers and the 3rd straight-through current transformer is connected using series system, collection electricity
Cable road head end A, B, C three-phase current differential waves；4th straight-through current transformer, the 5th straight-through current transformer and
6th straight-through current transformer is separately mounted to cable run end A, B, C threephase cable terminals bottom；4th punching electricity
The secondary coil of current transformer, the 5th straight-through current transformer and the 6th straight-through current transformer uses series system phase
Connection, gathers cable run end A, B, C three-phase current differential wave；The current transformer is open-close type current mutual inductance
Device, shell are insulated using unsaturated-resin；
The active power filtering amplifier is used to after filtering collection signal amplify, and is transmitted to Zigbee radio communication molds
Block；
The Zigbee wireless communication modules are used to receive current differential signal, and are transmitted to computer；The computer is used for
First and last end A, B are stored, C three-phase currents differential wave simultaneously calculates secondary differential values, then judges cable run insulation status.
2. a kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods as claimed in claim 1, its feature exist
In：The A, B, C three-phase current differential waves, including differential values between A, B, C three-phase current and A, B, C three-phase current it
Sum it is differential.
3. a kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods as claimed in claim 1, its feature exist
In：The A, B, C three-phase currents differential wave are differential and phase is differential forms by the amplitude of current signal.
4. a kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods as claimed in claim 1, its feature exist
In：The rated power of 6 straight-through current transformers is 5W, no-load voltage ratio 200/5, installed in Current Transformer Secondary side
6 sampling resistors are the accurate noninductive resistance of 0.2 Ω.
5. a kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods as claimed in claim 1, its feature exist
In：Collection cable run head end A, B, C the three-phase current differential wave or collection cable run head end A, B, C three-phase current are poor
The method of dynamic signal is specially：Three sampling resistors of head and end are connected respectively, A, B, C three-phase current signal vector additions, warp
Obtained after I/V conversions on sampling resistor.
6. a kind of high-voltage cable insulating on-Line Monitor Device based on double differential CT methods as claimed in claim 1, its feature exist
In：The active power filtering amplifier is powered using solar cell and super capacitor；The Zigbee wireless communication modules include
Microcontroller, RF transceivers and SPI interface；The RF transceivers are CC2420 radio frequency chips, working frequency 2.4GHz, data
Transmission rate 250kb/s；Pass through SPI interface and MSP430F149 single chip communications；With LABVIEW softwares point in the computer
Analysis calculates the change of first and last current signal, extracts characteristic signal, cable insulation is judged and sends early warning.
A kind of 7. high-voltage cable insulating on-line monitoring method based on double differential CT methods, it is characterised in that including：
Step a, A, B, C threephase cables head end electric current and end current are gathered respectively using current transformer and calculate A, B, C tri-
The sum of phase cable head electric current and the sum of A, B, C threephase cable end current；Current signal is filtered through active power filtering amplifier
Host computer is sent a signal to by Zigbee wireless communication modules after ripple amplification；
Step b, the differential of differential values and the sum of the three-phase current between cable end piece A, B, C three-phase current is calculated in host computer
Value, judges that end load changes；
Step c, while the differential values of the differential values and the sum of three-phase current between cable head A, B, C three-phase current are calculated, sentenced
Disconnected load and the asymmetric degree of cable leakage current；
Step d, the differential values of the sum of head end electric current are subtracted to the differential values of the sum of threephase cable end three-phase current again, obtain three
The secondary differential values of the sum of phase current are as the sum of threephase cable leakage current；By head end A, B is differential between C three-phase currents
Value subtracts end A, B, and the differential values between C three-phase currents, obtain the secondary differential values between three-phase current as threephase cable
The difference of leakage current；
Step e, judge whether phase and the setting insulation ag(e)ing early warning value of the sum of three-phase current secondary differential values are consistent, if differing
Step f is turned to during cause, step g is turned to when consistent；
Step f, the phase of secondary differential values between three-phase current and setting insulation ag(e)ing early warning value are compared, and judges each phase
Cable insulation aging character；
Step g, generation on-line monitoring report, including end A, B, the differential values between C three-phase currents；Head end A, B, C three-phase electricity
Differential values between stream；Secondary differential values between A, B, C three-phase current；The differential values of the sum of end A, B, C three-phase currents；It is first
Hold the differential values of the sum of A, B, C three-phase currents；The secondary differential values and cable run insulation analysis of the sum of A, B, C three-phase current
As a result.
A kind of 8. high-voltage line insulated on-line monitoring method based on double differential CT methods as claimed in claim 7, it is characterised in that：
The rated power of the current transformer is 5W, no-load voltage ratio 200/5,6 sampling resistors installed in Current Transformer Secondary side
It is the accurate noninductive resistance of 0.2 Ω.
9. a kind of high-voltage cable insulating on-line monitoring method based on double differential CT methods as claimed in claim 7, its feature exist
In：The collection A, B, C threephase cables head end electric current are specially with end current method：Three sampling resistor difference of head and end
Series connection, A, B, C three-phase current signal vector additions, obtain after sampled ohmically I/V conversions.
10. a kind of high-voltage cable insulating on-line monitoring method based on double differential CT methods as claimed in claim 7, its feature exist
In：The active power filtering amplifier is powered using solar cell and/or super capacitor；The Zigbee wireless communication modules bag
Include microcontroller, RF transceivers and SPI interface；The RF transceivers are CC2420 radio frequency chips, and working frequency 2.4GHz, counts
According to transmission rate 250kb/s；Pass through SPI interface and MSP430F149 single chip communications；LABVIEW softwares are used in the host computer
Analysis calculates the change of first and last current signal, extracts characteristic signal, cable insulation is judged and sends early warning.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711303073.8A CN108037423A (en) | 2017-12-08 | 2017-12-08 | A kind of high-voltage cable insulating on-Line Monitor Device and method based on double differential CT methods |
Applications Claiming Priority (1)
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| CN108548993A (en) * | 2018-06-08 | 2018-09-18 | 中国人民解放军海军工程设计研究院 | A kind of more cable parallel connection interlinkage fault-line selecting methods |
| CN109521340A (en) * | 2018-12-10 | 2019-03-26 | 珠海许继电气有限公司 | Distribution line insulation detection device and detection method |
| CN111025093A (en) * | 2019-11-19 | 2020-04-17 | 云南电网有限责任公司临沧供电局 | XLPE cable insulation life estimation method based on double-end balance factor |
| CN111157915A (en) * | 2019-12-31 | 2020-05-15 | 国网北京市电力公司 | Cable leakage current detection method and device, storage medium and processor |
| CN111679162A (en) * | 2020-06-02 | 2020-09-18 | 国网浙江义乌市供电有限公司 | Insulation monitoring method and device for transformer substation cable |
| CN113109662A (en) * | 2021-03-03 | 2021-07-13 | 中国电力科学研究院有限公司 | Method and system for determining relative aging degree of cable based on interphase relative dielectric loss |
| CN113702787A (en) * | 2021-09-15 | 2021-11-26 | 广东电网有限责任公司 | Method and device for detecting insulated wire of low-voltage line |
| CN117434357A (en) * | 2023-12-20 | 2024-01-23 | 天津航空机电有限公司 | Angular load balance detection circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108548993A (en) * | 2018-06-08 | 2018-09-18 | 中国人民解放军海军工程设计研究院 | A kind of more cable parallel connection interlinkage fault-line selecting methods |
| CN109521340A (en) * | 2018-12-10 | 2019-03-26 | 珠海许继电气有限公司 | Distribution line insulation detection device and detection method |
| CN111025093A (en) * | 2019-11-19 | 2020-04-17 | 云南电网有限责任公司临沧供电局 | XLPE cable insulation life estimation method based on double-end balance factor |
| CN111157915A (en) * | 2019-12-31 | 2020-05-15 | 国网北京市电力公司 | Cable leakage current detection method and device, storage medium and processor |
| CN111679162A (en) * | 2020-06-02 | 2020-09-18 | 国网浙江义乌市供电有限公司 | Insulation monitoring method and device for transformer substation cable |
| CN113109662A (en) * | 2021-03-03 | 2021-07-13 | 中国电力科学研究院有限公司 | Method and system for determining relative aging degree of cable based on interphase relative dielectric loss |
| CN113702787A (en) * | 2021-09-15 | 2021-11-26 | 广东电网有限责任公司 | Method and device for detecting insulated wire of low-voltage line |
| CN117434357A (en) * | 2023-12-20 | 2024-01-23 | 天津航空机电有限公司 | Angular load balance detection circuit |
| CN117434357B (en) * | 2023-12-20 | 2024-04-09 | 天津航空机电有限公司 | Angular load balance detection circuit |
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