CN106896275A - A kind of cable distributed capacitance Risk-warning control system - Google Patents
A kind of cable distributed capacitance Risk-warning control system Download PDFInfo
- Publication number
- CN106896275A CN106896275A CN201710075863.9A CN201710075863A CN106896275A CN 106896275 A CN106896275 A CN 106896275A CN 201710075863 A CN201710075863 A CN 201710075863A CN 106896275 A CN106896275 A CN 106896275A
- Authority
- CN
- China
- Prior art keywords
- distributed capacitance
- risk
- control system
- warning control
- cable distributed
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2605—Measuring capacitance
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The present invention relates to a kind of cable distributed capacitance Risk-warning control system, it is used to be monitored cable distributed capacitance, relay misoperation is prevented, the system includes the low frequency signal source being connected with dc bus positive pole and negative pole respectively and voltage balancing module and the small alternating current-direct current detection means being arranged at least one dc bus branch road.Compared with prior art, the present invention has the advantages that high security, high reliability, overall monitor, accurate measurement, easy to use, flexible economic.
Description
Technical field
The present invention relates to cable distributed capacitance monitoring field, more particularly, to a kind of control of cable distributed capacitance Risk-warning
System.
Background technology
When direct current is scurried into DC system grounding or exchange, loop can be constituted by the distribution capacity of cable, produce electric capacity
Electric current, causes the relay misoperation that some working values are low, sensitivity is high.The principal element of malfunction is the working value (electricity of relay
Pressure and power), cable distributed capacitance over the ground.《18 great anti-accident measures of power network of State Grid Corporation of China》From design angle
Degree makes corresponding requirements to actuating of relay power and operation voltage, but when there is DC earthing or exchange is sealed in, if control
The distribution capacity of cable exceedes critical value, and exit relay still can malfunction.
The content of the invention
The purpose of the present invention is exactly to provide a kind of high security, Gao Ke for the defect for overcoming above-mentioned prior art to exist
By property, overall monitor, accurate measurement, easy to use, flexible economic cable distributed capacitance Risk-warning control system.
The purpose of the present invention can be achieved through the following technical solutions：
A kind of cable distributed capacitance Risk-warning control system, is used to be monitored cable distributed capacitance, prevents relay
Device malfunction, the system includes the low frequency signal source being connected with dc bus positive pole and negative pole respectively and voltage balancing module and sets
Put the small alternating current-direct current detection means at least one dc bus branch road.
Described small alternating current-direct current detection means includes single-chip microcomputer and the DC detecting loop being connected with single-chip microcomputer respectively
With exchange measure loop, described DC detecting loop is provided with DC current sensor and first switch, described exchange inspection
Survey time, road was provided with AC current sensor and second switch.
Described first switch and the break-make mutual linking of second switch.
Described DC current sensor is magnetic saturation current sensor, and described AC current sensor is flux of magnetic induction
Current sensor.
The system also includes the microcomputer insulation tester being connected with dc bus positive pole and negative pole respectively.
Described microcomputer insulation tester model ATCWZJ5.
Described low frequency signal source is Portable insulation detector BXJY-A.
Small alternating current-direct current detection means on every dc bus branch road is equipped with a protection device.
The range of described DC current sensor is ± 30mA, and precision is 0.01mA, described AC current sensor
Range be ± 15mA, precision is 0.01mA.
Compared with prior art, the present invention has advantages below：
First, high security, high reliability
Small alternating current-direct current CT body product is small, improves operation margin of safety spatially in direct-current cabinet；Electric voltage equalization mould
Block take part in the balance control of busbar voltage, reduce variation degree.By the use of high reliability portable detector as
Low frequency signal occurring source, it is ensured that the operation reliably and with long-term of straight-flow system.
2nd, overall monitor, accurate measurement
Except being monitored with D.C. isolation, in addition to earthing wire-selecting, bus overvoltage/under-voltage monitoring function, also with exchange
Scurry into direct current branch failure monitoring, busbar voltage Balance route and distribution capacity on-line measurement function.Small alternating current-direct current CT is resistant to
By heavy current impact, being capable of accurate measurement for a long time.
3rd, easy to use, flexible economy
Primary clustering uses Distributed Design, and interface is simple, it is easy to which combination is installed, and system wiring is succinct, maintain easily with
Management；Economical and practical based on the extension that existing equipment is carried out, operating personnel need not retrain and can be used.
Brief description of the drawings
Fig. 1 is the trip(ping) circuit figure of belt length cable.
Fig. 2 is straight-flow system equivalent circuit diagram.
Fig. 3 is plus earth isoboles.
Fig. 4 is that relay positive supply is grounded isoboles.
Fig. 5 is on-line monitoring distribution capacity system diagram.
Fig. 6 is that alternating current-direct current Weak current detects block diagram.
Fig. 7 is voltage balancing module design drawing, wherein, it is front view to scheme (7a), and figure (7b) is left view, and figure (7c) is to bow
View.
Fig. 8 be voltage balancing module structure and control effect figure, wherein, figure (8a) be voltage balancing module circuit structure
Figure, figure (8b) is output waveform figure.
Fig. 9 is D.C. isolation monitoring system connection figure.
Wherein, 1, low frequency signal source, 2, voltage balancing module, 3, small alternating current-direct current detection means, 4, microcomputer Insulation monitoring
Instrument, 5, protection device, 31, single-chip microcomputer, 32, DC current sensor, 33, AC current sensor.
Specific embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.
Embodiment：
The hand of control box is jumped, three jump relays and failure protection start open one end into optocoupler it is general all with power cathode phase
Even, the other end is connected with control cable, as shown in figure 1, its equivalent circuit Fig. 2.In Fig. 1：T is protection act contact；TBJ is
Protection act relay；DL is switch auxiliary contact；TQ is breaking coil.E is equivalent source in Fig. 2；R1 and R2 are respectively just
Pole, the balanced bridge resistance of negative pole；R+ and R- are respectively the insulaion resistance of positive pole, negative pole；C+Positive pole, negative pole are respectively with C-
Distribution capacity；R is relay resistance；C is relay positive pole distribution capacity over the ground.The cable long of switch terminal case is caused, at it
There is larger distribution capacity between heart yearn and screen layer, when straight-flow system occurs one point earth, may cause to believe based on low frequency
The portable grounding resistance tester of number injection method is falsely dropped, or even causes the less relay of operating power or optocoupler to open into mistake
It is dynamic.
One point earth distribution capacity critical value analysis
(1) plus earth
Direct-flow positive pole ground connection (P points ground connection in Fig. 2), its equivalent circuit Fig. 3.Since moment is grounded, straight-flow system is led to
Relay is crossed to charge cable distributed capacitance.
Following relational expression can be obtained by KVL theorems：
Fig. 3 is the zero state response under a simple continuous current excitation, and association type (1) and formula (2) are solved：
uR(t)=Ee-t/RC (3)
Assuming that the actuation time of auxiliary reclay is td, the moment acts on the power P (t of relayd) be：
Operating power P according to relayR(5W or 7W), can ask for the critical value of distribution capacity, i.e. P (td)=PR：
Direct current negative pole ground connection (N points ground connection in Fig. 2), is shorted equal to relay R and distribution capacity C, and relay can not
Action, it will tripping.
(2) relay positive supply ground connection
Relay positive supply ground connection (Q points ground connection in Fig. 2), its isoboles is as shown in Figure 4.Straight-flow system passes through relay pair
Cable distributed capacitance charges, since moment is grounded.
The initial value and final value of relay both end voltage be：
Can be obtained according to KCL laws：
Solve relay both end voltage uRFor：
Wherein, τ=(R1//R2//R+//R-//R)·(C+//C-)。
Distribution capacity critical value analysis when exchange is sealed in
(1) Analysis on Mechanism
When AC power scurries into straight-flow system from bus, loop will be constituted by cable distributed capacitance C.Total loop impedance
For：
Z=R+1/ (j ω C) (10)
The voltage for being added in relay is：
uR=us/[1+1/(jωRC)] (11)
When AC power is scurried into from relay by cable side, loop will be constituted by cable distributed capacitance C-, calculated
Journey is ibid.usTo scurry into the voltage of exchange.
(2) critical value is asked for
If the voltage u being added on relayRHigher than actuating of relay voltage in change procedure, and power is opened more than power
Dynamic value Pd, then relay misoperation can be caused.
The power for acting on relay is：
P=uR 2/R (12)
The critical value that actuating of relay power P d asks for distribution capacity is equal to according to P.
When critical value of the distribution capacity more than distribution capacity, then power is met more than energetic start up value.Monitoring distribution capacity
Size, when distribution capacity is close to critical value, then early warning.
Distribution capacity is monitored on-line
When distribution capacity is greatly when actuating of relay power is met, during direct current single-point grounding relay still can malfunction, therefore
Need the distribution capacity of on-line checking branch road.
Frequency and voltage are set using portable mobile device, make to produce low-frequency ac signal on dc bus, if certain is propped up
The exchange CT detection means on road can detect corresponding AC signal, then it is measurable go out the branch road distribution capacity, and meet corresponding
Standard.The technical scheme of on-line measurement distribution capacity is as shown in Figure 5.
Note 1 provides rational low-frequency ac signal in Fig. 5；But lack ac signal measurement CT, it is necessary to newly-increased, such as Fig. 5 notes 2
It is shown；In order to meet the requirement of steady, accurate measurement distribution capacity, busbar voltage balancer need to be designed, as shown in Fig. 5 notes 3.
A kind of sensor (small alterating and direct current flow detection device) is designed, while can detect that DC Weak currents signal and AC are micro-
Small AC signal, small ac and dc current detection is as shown in Figure 6：DC Weak currents Cleaning Principle is magnetic saturation principle, uses phase
The oscillating circuit or modulation pulse detection magnetic field intensity of pass react corresponding DC current；AC Weak currents Cleaning Principle is magnetic flux
Principle of induction, can directly be induced the alternating current of correlation by induction coil.DC Cleaning Principles and AC Cleaning Principle mutual exclusions, make
Switched with same coil, reduce cost and volume.
DC electric current sensor starts：K1 closes, and K2 disconnects, DC electric current working sensor, and PWM or ADC outputs may be selected.AC
Current sensor starts：K1 disconnects, K2 closures, the work of AC current sensors.Small ac and dc current detection sensor parameter is such as
Under：DC, minimum current accuracy of detection is detected for ± minimum current；AC, minimum current accuracy of detection is detected for ± minimum current.
Historical data to earth resistance carries out trend analysis, not only facilitates dielectric level and the change of analysis secondary circuit
Change speed, find the early-warning point that insulation drastically declines, realize the repair based on condition of component of secondary cable；Additionally aid on-line monitoring CT drifts
Situation, assessment heater effect on moisture extraction etc..When there is Back Up in earth resistance trend, it may be possible to which CT drifts cause.When connecing
Ground resistance accelerates to diminish, it may be possible to which the external cause such as make moist.
Busbar voltage Balance route
After there is busbar voltage skew, power electronic element is controlled by gathering busbar voltage so that the negative mother of positive pole
Equivalent resistance is equal, reaches the negative mother's balance of voltage of positive pole.Voltage balancing module is designed as shown in fig. 7, for direct current negative terminal over the ground
One regulated ground resistance of pin, realizes the pressure difference absolute value of system positive and negative busbar voltage-to-ground no more than rated voltage
55% of 10%, i.e. straight-flow system negative pole (bus) voltage-to-ground no more than rated voltage.Wherein, voltage measurement is fixed amount
Journey, DC：300V, AC：250V.
After there is voltage bus skew, voltage balancing module is passed through using the constant-resistance pattern in DC Electronic Loads
Adjust electric current to reach constant-resistance pattern, its effect is as shown in Figure 8.In figure (8a), when R4 is 1%, if input voltage is 1V, that
U1 (LM358)+on voltage be 10mV, it is 10mV also just control voltage on R1, that is, flow through the electric current I=10mV/ of R1
0.01 Ω=0.01V/0.01 Ω=1A, so that the resistance value RL=1V/1A=1 Ω of equivalent electronic load.It is defeated from figure (8b)
Go out waveform it can be seen that the electronic load of hardware design is pure resistance attribute.
The system is examined by microcomputer insulating monitor ATCWZJ5, small alternating current-direct current CT, voltage balancing module and Portable insulation
Survey instrument BXJY-A (offer low frequency signal) to constitute, system connection figure is as shown in Figure 9.On the basis of monitoring Grounding Resistance for Direct-Current System
On, the further on-line monitoring function of increasing to distribution capacity, trend analysis and Risk-warning.
Claims (9)
1. a kind of cable distributed capacitance Risk-warning control system, is used to be monitored cable distributed capacitance, prevents relay
Malfunction, it is characterised in that the system includes that the low frequency signal source (1) being connected with dc bus positive pole and negative pole respectively and voltage are equal
Weighing apparatus module (2) and the small alternating current-direct current detection means (3) being arranged at least one dc bus branch road.
2. a kind of cable distributed capacitance Risk-warning control system according to claim 1, it is characterised in that described is micro-
DC detecting loop and exchange that small alternating current-direct current detection means (3) is connected including single-chip microcomputer (31) and respectively with single-chip microcomputer (31)
Measure loop, described DC detecting loop is provided with DC current sensor (32) and first switch (K1), described exchange
Measure loop is provided with AC current sensor (33) and second switch (K2).
3. a kind of cable distributed capacitance Risk-warning control system according to claim 2, it is characterised in that described
The break-make mutual linking of one switch (K1) and second switch (K2).
4. a kind of cable distributed capacitance Risk-warning control system according to claim 2, it is characterised in that described is straight
Stream current sensor (32) is magnetic saturation current sensor, and described AC current sensor (33) is flux of magnetic induction current sense
Device.
5. a kind of cable distributed capacitance Risk-warning control system according to claim 1, it is characterised in that the system is also
Including the microcomputer insulation tester (4) being connected with dc bus positive pole and negative pole respectively.
6. a kind of cable distributed capacitance Risk-warning control system according to claim 5, it is characterised in that described is micro-
Machine insulation tester (4) model ATCWZJ5.
7. a kind of cable distributed capacitance Risk-warning control system according to claim 1, it is characterised in that described is low
Frequency source signal (1) is Portable insulation detector BXJY-A.
8. a kind of cable distributed capacitance Risk-warning control system according to claim 1, it is characterised in that every direct current
Small alternating current-direct current detection means (3) on bus branch road is equipped with a protection device (5).
9. a kind of cable distributed capacitance Risk-warning control system according to claim 2, it is characterised in that described is straight
The range of stream current sensor (32) is ± 30mA, and precision is 0.01mA, and the range of described AC current sensor (33) is
± 15mA, precision is 0.01mA.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710075863.9A CN106896275A (en) | 2017-02-13 | 2017-02-13 | A kind of cable distributed capacitance Risk-warning control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710075863.9A CN106896275A (en) | 2017-02-13 | 2017-02-13 | A kind of cable distributed capacitance Risk-warning control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106896275A true CN106896275A (en) | 2017-06-27 |
Family
ID=59198055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710075863.9A Pending CN106896275A (en) | 2017-02-13 | 2017-02-13 | A kind of cable distributed capacitance Risk-warning control system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106896275A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108710016A (en) * | 2018-03-01 | 2018-10-26 | 华南理工大学 | A kind of computational methods of the single-core cable distributed electrical capacitance current of the golden cloth containing insulation |
| CN113341231A (en) * | 2021-05-26 | 2021-09-03 | 合肥同智机电控制技术有限公司 | High-voltage direct-current bus distributed capacitance detection protection method |
| CN114614448A (en) * | 2020-12-09 | 2022-06-10 | 西门子股份公司 | DC switch |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203672938U (en) * | 2013-11-06 | 2014-06-25 | 北京柏艾斯科技有限公司 | AC-DC universal leakage-current sensor |
| CN204536971U (en) * | 2015-03-24 | 2015-08-05 | 深圳奥特迅电力设备股份有限公司 | DC bus voltage-to-ground equalizing circuit and Insulation Inspection Device for Direct-Current System |
| CN105044519A (en) * | 2015-08-06 | 2015-11-11 | 国网上海市电力公司 | On-line identification method for DC interconnection and mixed use of transformer station |
| CN205880062U (en) * | 2016-07-08 | 2017-01-11 | 浙江科畅电子有限公司 | Portable DC power supply return circuit capacitance to ground tester |
-
2017
- 2017-02-13 CN CN201710075863.9A patent/CN106896275A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN203672938U (en) * | 2013-11-06 | 2014-06-25 | 北京柏艾斯科技有限公司 | AC-DC universal leakage-current sensor |
| CN204536971U (en) * | 2015-03-24 | 2015-08-05 | 深圳奥特迅电力设备股份有限公司 | DC bus voltage-to-ground equalizing circuit and Insulation Inspection Device for Direct-Current System |
| CN105044519A (en) * | 2015-08-06 | 2015-11-11 | 国网上海市电力公司 | On-line identification method for DC interconnection and mixed use of transformer station |
| CN205880062U (en) * | 2016-07-08 | 2017-01-11 | 浙江科畅电子有限公司 | Portable DC power supply return circuit capacitance to ground tester |
Non-Patent Citations (1)
| Title |
|---|
| 上海超高压输变电公司: "《超高压输变电操作技能培训教材 交直流电源与测量表计 第五册》", 31 August 2005 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108710016A (en) * | 2018-03-01 | 2018-10-26 | 华南理工大学 | A kind of computational methods of the single-core cable distributed electrical capacitance current of the golden cloth containing insulation |
| CN108710016B (en) * | 2018-03-01 | 2019-10-18 | 华南理工大学 | A kind of calculation method of the single-core cable distributed electrical capacitance current containing the golden cloth that insulate |
| CN114614448A (en) * | 2020-12-09 | 2022-06-10 | 西门子股份公司 | DC switch |
| EP4012926A1 (en) * | 2020-12-09 | 2022-06-15 | Siemens Aktiengesellschaft | Direct current switch |
| US11601124B2 (en) | 2020-12-09 | 2023-03-07 | Siemens Aktiengesellschaft | DC switch |
| CN113341231A (en) * | 2021-05-26 | 2021-09-03 | 合肥同智机电控制技术有限公司 | High-voltage direct-current bus distributed capacitance detection protection method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103782509B (en) | For detecting system, computer program and the method for the internal winding failure of synchronous generator | |
| CN108054764A (en) | A kind of multifunctional ligand power grid flexible ground device and control method | |
| CN104777397A (en) | Distribution line single-phase break line judgment and positioning method based on line voltage vector criterion | |
| CN204882720U (en) | Intelligent computer direct current system monitoring facilities | |
| CN207705796U (en) | A kind of multifunctional ligand power grid flexible ground device | |
| CN108646125B (en) | Method, device and system for testing capacitance current | |
| CN106896275A (en) | A kind of cable distributed capacitance Risk-warning control system | |
| CN106771901A (en) | Based on the DC system insulating monitoring method for determining frequency switching resistance principle | |
| CN103840438A (en) | Intelligent detecting system for detecting single phase grounding protection function of intelligent switch device based on 10kV neutral non-grounding distribution network system | |
| CN110174585A (en) | A kind of recognition methods of the high-voltage capacitor open circuit fault of double tunning alternating current filter | |
| CN104330687A (en) | Method and device for detecting electricity leakage fault of power supply system | |
| CN103454544A (en) | Linear field suppression circuit detection method based on electronic jumper | |
| CN103983895B (en) | The online N line multipoint earth faults detection method of PT secondary circuit | |
| CN109375120A (en) | The monitoring method of alternating current is scurried into DC power system | |
| CN104251978B (en) | Straight-flow system exchanges the test device that crosstalk and voltage pulsation influence on relay | |
| CN202166682U (en) | Fault detecting device of direct grounding | |
| CN105244853B (en) | A kind of transforming plant DC power-supply system for possessing ground connection inspection route selection Checking Mechanism | |
| CN105242171B (en) | A kind of transforming plant DC ground connection inspection device for possessing route selection Checking Mechanism | |
| CN105259483B (en) | A kind of generator amature winding is to iron core and the insulation measurement method of shafting | |
| CN103884930A (en) | Full bridge uncontrolled rectifier fault diagnosis method based on insulation monitoring | |
| CN208043943U (en) | A kind of capacitance current test device and system based on switch cabinet electrified instruction device | |
| CN108548982B (en) | Method, device and system for testing capacitance current | |
| CN204179639U (en) | Intelligent leakage circuit breaker | |
| CN207705795U (en) | A kind of novel mixed topology multifunctional electric power network distribution device | |
| CN106443382A (en) | Three-phase AC IT system insulating performance online detection apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20170627 |
|
| RJ01 | Rejection of invention patent application after publication |