CN201607488U - DC resistance measuring device of ultra-high-voltage transmission line - Google Patents
DC resistance measuring device of ultra-high-voltage transmission line Download PDFInfo
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- CN201607488U CN201607488U CN2009202871641U CN200920287164U CN201607488U CN 201607488 U CN201607488 U CN 201607488U CN 2009202871641 U CN2009202871641 U CN 2009202871641U CN 200920287164 U CN200920287164 U CN 200920287164U CN 201607488 U CN201607488 U CN 201607488U
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Abstract
The utility model relates to a DC resistance measuring device of an ultra-high-voltage transmission line, which comprises a DC resistance tester, and a protecting resistor. The protecting resistor is connected with the tested line in parallel and then is connected with a measuring port of the DC resistance tester. Compared with the prior art, the measuring device has advantages of high measuring accuracy, good safety, and ensuring of safety of testing personnel.
Description
Technical field
The utility model relates to the measurement of extra high voltage network parameter, especially relates to a kind of direct current resistance measurement mechanism of extra high voltage network.
Background technology
Newly-built 110～500kV overhead power line engineering, by " overhead power line construction inspection rules " (GBBJ-1233-90) and " 110kV and above transmission and transformation engineering and final acceptance of construction standard " requirement (DL/7782-90), after the completion of works acceptance(check), must carry out the parameter measurement test.Without test judge qualified before, must not put into operation.Direct current resistance is exactly one of them important parameter; actual foundation as work such as computing system short-circuit current, relay protection setting, the distribution of reckoning trend and selection reasonable Operation Mode; simultaneously also can check whether the connection of lead is good, find the hidden defective that may stay in the construction early according to the data of direct current resistance.Therefore improve accuracy that direct current resistance measures and extremely important meaning is all arranged for the check of running protection and capital construction.
The fast development of Shanghai Power Network system in recent years, the transmission line of electricity corridor is also more and more crowded, the two-circuit joint use or on same transmission line of electricity corridor runs parallel circuit situation just be difficult to avoid.Owing to exist the effect of electromagnetic coupled between the parallel circuit, can produce induced electricity on the test line.Faradic existence not only influences the accuracy of parameter measurement, and directly jeopardizes measuring equipment and tester's safety.
In the on-the-spot actual tests process, we find that the induced voltage numerical value on many tested transmission lines of electricity is very high.Though we are to existing induced voltage to consider to some extent on the transmission line of electricity before.But the farsighted value that surpasses our expection of induced voltage numerical value, even the inductive voltage value of the test line that has has surpassed the magnitude of voltage that the class of insulation of 3381 instrument for measuring DC resistance can bear.For preventing to respond to the harm of high pressure, carry out one point earth at the end of test line, the induced voltage at top is dropped to 0.But when we used 3381 instrument for measuring DC resistance to measure, resistance value that it records and theoretical value be deviation slightly, sometimes surveying instrument even fault has taken place.Obviously, under the almost nil condition of induced voltage, faradic interference and harm are but also potential.
As shown in Figure 1, draw according to original testing scheme and to have connected equivalent circuit diagram behind the equipment, by equivalent circuit diagram as can be seen, do not had though test preceding top induced voltage,, made measuring junction two-phase circuit and surveying instrument constitute the loop owing to inserted 3381 instrument for measuring DC resistance, produced induction current Ig, faradic inflow has been added on the tested resistance, makes its both end voltage VX raise, and causes to measure to produce error.Might make the too high of VX liter if induction current is higher and cause device damage.
Summary of the invention
The purpose of this utility model is exactly the direct current resistance measurement mechanism that a kind of measuring accuracy height, extra high voltage network that security is good are provided in order to overcome the defective that above-mentioned prior art exists.
The purpose of this utility model can be achieved through the following technical solutions:
A kind of direct current resistance measurement mechanism of extra high voltage network is characterized in that, comprises instrument for measuring DC resistance, protective resistance, is connected with the test port of instrument for measuring DC resistance after described protective resistance and the test line parallel connection.
Described instrument for measuring DC resistance comprises stabilized current supply, measuring resistance, discharge coil, decay circuit, back-emf protection module, A/D modular converter, computing machine, display; it is in parallel after described measuring resistance is connected with circuit-under-test with discharge coil; described stabilized current supply two terminates at the discharge coil two ends; described back-emf protection module is connected on the circuit-under-test two ends; described decay circuit is connected with two ends, back-emf protection module, the A/D modular converter of measuring resistance respectively, and described computing machine is connected with A/D modular converter, display respectively.
The resistance of described protective resistance is 100～150 times of resistance of test line.
Compared with prior art, the utility model measuring accuracy height, security is good, ensures tester's safety.
Description of drawings
Fig. 1 is the equivalent circuit diagram of the prior art of direct current resistance measurement;
Fig. 2 is an equivalent circuit diagram of the present utility model;
Fig. 3 is the structural representation of the utility model instrument for measuring DC resistance.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is elaborated.
As shown in Figure 2, a kind of direct current resistance measurement mechanism of extra high voltage network comprises instrument for measuring DC resistance 1, protective resistance R, is connected with the test port of instrument for measuring DC resistance 1 after described protective resistance R and test line Ra, the Rb parallel connection.
In parallel connection after the protective resistance, when induction current Ig occurred, induction current Ig can constitute the loop by resistance R, and is unlikely in the inflow equipment.Be a constant current source in the equipment, from external loop, its port resistance can be similar to infinity, and resistance R is compared little a lot with it, and electric current can be similar to be thought and flow through through resistance R entirely.But after the measuring current of equipment was flowed out by equipment, because the resistance R a of the resistance R that inserts on the circuit can be similar to and think that resistance R does not cause too big shunting, the precision of measurement still can be guaranteed.The resistance that equipment is surveyed after inserting can be regarded as line resistance Ra and inserts the parallel connection value of resistance R.
Make measuring error less than 2% in order to reach group goal, the resistance that inserts carried out theoretical calculation:
About the line length average out to 10km in general area, Shanghai; model is two divisural lines of JL/1A-630/45; then the direct current resistance of single-phase transmission line is about 0.2 Ω, so according to calculating, our scene selects for use the slide wire resistance of 100 times of Ra (20 Ω) as the protective resistance R that inserts.
As shown in Figure 3; described instrument for measuring DC resistance 1 comprises stabilized current supply 11; measuring resistance Rn; discharge coil 12; decay circuit 14; back-emf protection module 13; A/D modular converter 15; computing machine 16; display 17; it is in parallel after described measuring resistance Rn connects with circuit-under-test with discharge coil 12; described stabilized current supply terminates at discharge coil 12 two ends for 11 liang; described back-emf protection module 13 is connected on the circuit-under-test two ends; described decay circuit 14 respectively with the two ends of measuring resistance Rn; back-emf protection module 13; A/D modular converter 15 connects, described computing machine 16 respectively with A/D modular converter 15; display 17 connects.W represents product to be tested among the figure, R
XDirect current resistance for product to be tested, when K switch is closed, stabilized current supply is powered to product to be tested, because product to be tested has the reaction electric current not suddenly change, power work is in the unsteady flow state at the beginning, along with the time increases, supply current increases gradually, when reaching the current stabilization electric current of instrument setting, and instrument work and current stabilization state, at this moment the dI/dt=0 product to be tested shows as pure resistive state, measurement standard resistance R n and product to be tested W two ends potential difference (PD) V
N, V
XThe direct current resistance R of product to be tested as can be known just
X
Claims (3)
1. the direct current resistance measurement mechanism of an extra high voltage network is characterized in that, comprises instrument for measuring DC resistance, protective resistance, is connected with the test port of instrument for measuring DC resistance after described protective resistance and the test line parallel connection.
2. the direct current resistance measurement mechanism of a kind of extra high voltage network according to claim 1; it is characterized in that; described instrument for measuring DC resistance comprises stabilized current supply; measuring resistance; discharge coil; the decay circuit; the back-emf protection module; the A/D modular converter; computing machine; display; it is in parallel after described measuring resistance is connected with circuit-under-test with discharge coil; described stabilized current supply two terminates at the discharge coil two ends; described back-emf protection module is connected on the circuit-under-test two ends; described decay circuit respectively with the two ends of measuring resistance; the back-emf protection module; the A/D modular converter connects, described computing machine respectively with the A/D modular converter; display connects.
3. the direct current resistance measurement mechanism of a kind of extra high voltage network according to claim 1 is characterized in that, the resistance of described protective resistance is 100～150 times of resistance of test line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202871641U CN201607488U (en) | 2009-12-31 | 2009-12-31 | DC resistance measuring device of ultra-high-voltage transmission line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202871641U CN201607488U (en) | 2009-12-31 | 2009-12-31 | DC resistance measuring device of ultra-high-voltage transmission line |
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| Publication Number | Publication Date |
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| CN201607488U true CN201607488U (en) | 2010-10-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2009202871641U Expired - Fee Related CN201607488U (en) | 2009-12-31 | 2009-12-31 | DC resistance measuring device of ultra-high-voltage transmission line |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102981058A (en) * | 2012-12-05 | 2013-03-20 | 辽宁省电力有限公司抚顺供电公司 | Anti-interference direct current resistance testing device |
-
2009
- 2009-12-31 CN CN2009202871641U patent/CN201607488U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102981058A (en) * | 2012-12-05 | 2013-03-20 | 辽宁省电力有限公司抚顺供电公司 | Anti-interference direct current resistance testing device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101013 Termination date: 20181231 |
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| CF01 | Termination of patent right due to non-payment of annual fee |