CN103743935A - Method for measuring system capacitance current in power supply system in coalmine production - Google Patents
Method for measuring system capacitance current in power supply system in coalmine production Download PDFInfo
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- CN103743935A CN103743935A CN201310741809.5A CN201310741809A CN103743935A CN 103743935 A CN103743935 A CN 103743935A CN 201310741809 A CN201310741809 A CN 201310741809A CN 103743935 A CN103743935 A CN 103743935A
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Abstract
The invention discloses a method for measuring a system capacitance current in a power supply system in coalmine production. Three primary-side phase lines of a busbar of the power supply system are connected to the primary side of a voltage transformer. The method for measuring the system capacitance current in the power supply system in coalmine production is characterized by comprising the following steps: respectively connecting the primary-side phase lines of the busbar with a measurement capacitor by virtue of isolation disconnecting links, grounding the measurement capacitor by virtue of a current measuring device; measuring the voltage of a secondary-side measuring line; closing the isolation disconnecting links of the measurement capacitor and the primary-side phase line, acquiring the current of the measurement capacitor, and acquiring a measured zero-sequence opening triangular voltage; calculating the system capacitance current. According to the method, the measurement capacitor is respectively connected with the primary-side phase lines so as to be measured. The operation method is simple, the testing time is improved, the testing result is more accurate and more stable; meanwhile, the measurement capacitor is adopted, so that the breakdown possibility is less; compared with the existing method of adopting a resistor for measurement, the method disclosed by the invention is relatively higher in safety.
Description
Technical field
The present invention relates to transformer station's correlative technology field, particularly a kind of system capacitive current measuring method of the electric power system for coal production.
Background technology
The electricity consumption that is used for the transformer station of colliery system has clear and definite safety requirements, in < < safety regulations in coal mine > >, clearly stipulate, single-phase-to-ground current is no more than 20A, relate to the particular surroundings of high gas under electric arc that trouble spot ground current forms and coal mine, eliminate the electric arc of trouble spot ground current, avoid the gas explosion causing because of arc light, there is very important effect.Therefore, for the capacity of arc suppression coil under selecting properly different running method and the mode of extinguishing arc, reach the requirement that reduces system capacitive current, need to carry out Measurement accuracy to the system capacitive current of electric power system.
The existing system capacitive current measuring method to electric power system is high resistance method, yet high resistance method testing capacitor current practice process is numerous and diverse, resistance easily heating is breakdown, test result out of true, undulatory property is large and dangerous high, easily causes the person and equipment breakdown.
Summary of the invention
Based on this, be necessary to adopt high resistance method to measure the system capacitive current for the electric power system of coal production for prior art, test result out of true, undulatory property is large and dangerous high, easily cause the technical matters of the person and equipment breakdown, a kind of system capacitive current measuring method of the electric power system for coal production is provided.
A kind of system capacitive current measuring method of the electric power system for coal production, the primary side of three primary side phase line access voltage transformer (VT) of the bus of described electric power system, the system capacitive current measuring method of the described electric power system for coal production comprises:
Further, described step 12 specifically comprises: measure respectively three secondary side line voltages of described voltage transformer secondary side, calculate the mean value of three secondary side line voltages as secondary side slotted line voltage.
Further, carrying out between described step 11 and step 12, also comprise: measure the zero sequence open delta voltage of described voltage transformer secondary side as opening voltage.
Further, if described opening voltage is greater than default load balance threshold value, described step 13 specifically comprises:
The isolation switch of described measurement electric capacity and the first primary side phase line closes, obtain the current measurement value of described current measuring device as the first capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the first zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the first primary side phase line, wait for described measurement capacitor discharge;
The isolation switch of described measurement electric capacity and the second primary side phase line closes, obtain the current measurement value of described current measuring device as the second capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the second zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the second primary side phase line, wait for described measurement capacitor discharge;
The isolation switch of described measurement electric capacity and the 3rd primary side phase line closes, obtain the current measurement value of described current measuring device as the 3rd capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the 3rd zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the 3rd primary side phase line;
Described measurement capacitance current is the mean value of described the first capacitance current, the second capacitance current and the 3rd capacitance current, and described measurement zero sequence open delta voltage is the mean value of described the first zero sequence open delta voltage, the second zero sequence open delta voltage and the 3rd zero sequence open delta voltage.
Further, if described opening voltage is less than or equal to default load balance threshold value, described step 13 specifically comprises:
The isolation switch of described measurement electric capacity and one of them primary side phase line closes, obtain the current measurement value of described current measuring device as measuring capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as measuring zero sequence open delta voltage.
Further, described step 14 specifically comprises:
Calculate described system capacitive current=secondary side slotted line voltage/measurement zero sequence open delta voltage * measurement capacitance current.
Further, carrying out between described step 11 and step 12, also comprising: exiting the arc suppression coil being connected with electric power system, disconnect the load on the zero sequence open delta voltage of described voltage transformer secondary side.
Further, the load on the zero sequence open delta voltage of described voltage transformer secondary side is secondary resonance eliminator.
Further, three of described bus primary side phase lines are also connected with isolation switch by disconnector, isolating switch respectively successively.
The present invention, by being connected respectively with primary side phase line measuring electric capacity, measures.Method of operating is simple, has improved the test duration, and test result more accurately and stable, meanwhile, is measured electric capacity owing to adopting, and is not easy breakdownly, and with respect to the method for existing employing resistance measurement, security is relatively high.
Accompanying drawing explanation
Fig. 1 is the workflow diagram of the system capacitive current measuring method of a kind of electric power system for coal production of the present invention;
Fig. 2 is the schematic diagram of electric power system;
Fig. 3 is the workflow diagram of an example of system capacitive current measuring method of a kind of electric power system for coal production of the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention will be further described in detail.
Be illustrated in figure 1 the workflow diagram of the system capacitive current measuring method of a kind of electric power system for coal production of the present invention, wherein, be illustrated in figure 2 the circuit connection diagram while measuring.Three of the bus of electric power system primary side phase line 221(A phases as shown in Figure 2), 222(B phase), 223(C phase) be connected with the primary side of voltage transformer (VT) 21 respectively, the system capacitive current measuring method of the described electric power system for coal production, comprises as shown in Figure 1:
Mode with respect to existing employing resistance measurement, adopt electric capacity to measure, because electric capacity has power-on time, the time of the isolation switch of described measurement electric capacity and the primary side phase line of therefore closing can be longer, and can be not breakdown, therefore the precision of test result is higher, can reduce the risk of personal injury simultaneously.
In an embodiment, described step 12 specifically comprises therein: measure respectively three secondary side line voltages of described voltage transformer secondary side, calculate the mean value of three secondary side line voltages as secondary side slotted line voltage.
By testing three secondary side line voltages, average, the accuracy of secondary side slotted line voltage is higher.
In an embodiment, carrying out between described step 11 and step 12, also comprise: measure the zero sequence open delta voltage of described voltage transformer secondary side as opening voltage therein.
In an embodiment, if described opening voltage is greater than default load balance threshold value, described step 13 specifically comprises therein:
The isolation switch of described measurement electric capacity and the first primary side phase line 221 closes, obtain the current measurement value of described current measuring device as the first capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the first zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the first primary side phase line 221, wait for described measurement capacitor discharge;
The isolation switch of described measurement electric capacity and the second primary side phase line 222 closes, obtain the current measurement value of described current measuring device as the second capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the second zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the second primary side phase line 222, wait for described measurement capacitor discharge;
The isolation switch of described measurement electric capacity and the 3rd primary side phase line 223 closes, obtain the current measurement value of described current measuring device as the 3rd capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the 3rd zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the 3rd primary side phase line 223;
Described measurement capacitance current is the mean value of described the first capacitance current, the second capacitance current and the 3rd capacitance current, and described measurement zero sequence open delta voltage is the mean value of described the first zero sequence open delta voltage, the second zero sequence open delta voltage and the 3rd zero sequence open delta voltage.
Preferably, described default load balance threshold value is 0.4 volt.Wherein, when opening voltage is greater than default load balance threshold value, be illustrated in the laod unbalance on the zero sequence open delta voltage of described voltage transformer secondary side, A now, B, system capacitive current on C three-phase is not identical, therefore, respectively to the first primary side phase line 221, the second primary side phase line 222 and the 3rd primary side phase line 223 are measured, by computation and measurement capacitance current, it is described the first capacitance current, the mean value of the second capacitance current and the 3rd capacitance current, measuring zero sequence open delta voltage is described the first zero sequence open delta voltage, the mean value of the second zero sequence open delta voltage and the 3rd zero sequence open delta voltage, thereby obtain suitable system capacitive current.
Further, if described opening voltage is less than or equal to default load balance threshold value, described step 13 specifically comprises:
The isolation switch of described measurement electric capacity and one of them primary side phase line closes, obtain the current measurement value of described current measuring device as measuring capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as measuring zero sequence open delta voltage.
Preferably, described default load balance threshold value is 0.4 volt.Wherein, when opening voltage is less than or equal to default load balance threshold value, be illustrated in the load balance on the zero sequence open delta voltage of described voltage transformer secondary side, now the system capacitive current on A, B, C three-phase is identical, therefore, only need to measure any road of the first primary side phase line 221, the second primary side phase line 222 and the 3rd primary side phase line 223, can obtain suitable system capacitive current.
In an embodiment, described step 14 specifically comprises therein:
Calculate described system capacitive current=secondary side slotted line voltage/measurement zero sequence open delta voltage * measurement capacitance current.
Therein in an embodiment, carrying out between described step 11 and step 12, also comprising: exiting the arc suppression coil being connected with electric power system, disconnect the load on the zero sequence open delta voltage of described voltage transformer secondary side.Arc suppression coil can produce certain building-out capacitor electric current, causes interference, exits the arc suppression coil being connected with electric power system and can reduce measurements interference.
Further, the load on the zero sequence open delta voltage of described voltage transformer secondary side is secondary resonance eliminator.
Secondary resonance eliminator also can produce and disturb computing system capacitance current, therefore disconnects secondary resonance eliminator and can reduce calculating interference.
Further, three of described bus primary side phase lines are also connected with isolation switch by disconnector, isolating switch respectively successively.Disconnector 261,262 and 263 is controlled respectively the first primary side phase line 221, the second primary side phase line 222 is connected with isolating switch 27 with the 3rd primary side phase line 223.Wherein, disconnector 261,262,263 and isolating switch 27 are all placed in the reserve tank of electric power system, and are connected with the 3rd primary side phase line 223 with the first primary side phase line 221, the second primary side phase line 222, therefore, the present embodiment is only to use existing equipment setting, safer convenience.
As an example of the present invention, its workflow as shown in Figure 3, comprising:
Step S301, first exits the arc suppression coil in electric power system before measurement, and the load on the zero sequence open delta voltage of described voltage transformer secondary side is broken;
Step S302, measures the zero sequence open delta voltage U0 of described voltage transformer secondary side with multimeter;
Step S303, measures and records secondary side line voltage U AB, UBC and UAC;
Step S304, calculates UL=(UAB+UBC+UAC)/3;
Step S305, test connection is complete according to connecting shown in Fig. 2, and check errorless;
Step S306, measures the first primary side phase line 221, and the isolation switch that first closes makes the first primary side phase line 221 be connected with measurement electric capacity 24, then the isolating switch that closes.With multimeter, measure the zero sequence open delta voltage Ujd01 value of described voltage transformer secondary side simultaneously, observe current measuring device reading I1 value, and record;
Step S307, finishes the measurement to the first primary side phase line 221, first cut-off breaker, then disconnect isolation switch, and will measure capacitor discharge;
Step S308, if U0>0.4V performs step S309, otherwise makes I=I1, Ujd0=Ujd01, execution step S312
Step S309, measures the second primary side phase line 222, and the isolation switch that first closes makes the second primary side phase line 222 be connected with measurement electric capacity 24, then the isolating switch that closes.With multimeter, measure the zero sequence open delta voltage of described voltage transformer secondary side simultaneously, observe current measuring device reading I2 value, and record;
Step S310, finishes the measurement to the second primary side phase line 222, first cut-off breaker, then disconnect isolation switch, and will measure capacitor discharge;
Step S311, measures the 3rd primary side phase line 223, and the isolation switch that first closes makes the 3rd primary side phase line 223 be connected with measurement electric capacity 24, then the isolating switch that closes.With multimeter, measure the zero sequence open delta voltage Ujd03 value of described voltage transformer secondary side simultaneously, observe current measuring device reading I3 value, and record;
Step S312, finishes the measurement to the 3rd primary side phase line 223, first cut-off breaker, then disconnect isolation switch, and will measure capacitor discharge;
Step S313, makes I=(I1+I2+I3)/3, Ujd0=(Ujd01+Ujd02+Ujd03)/3;
Step S314, computing system capacitance current IC=(UL/Ujd0) * I.
The above embodiment has only expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (9)
1. the system capacitive current measuring method for the electric power system of coal production, the primary side of three primary side phase line access voltage transformer (VT) of the bus of described electric power system, it is characterized in that, the system capacitive current measuring method of the described electric power system for coal production comprises:
Step (11), is connected by isolation switch three primary side phase lines of described bus respectively with measurement electric capacity, described measurement electric capacity is by current measuring device ground connection;
Step (12), measures the secondary side line voltage of described voltage transformer secondary side, obtains secondary side slotted line voltage;
Step (13), the isolation switch of described measurement electric capacity and primary side phase line that closes, obtains the current measurement value of described current measuring device, obtains measuring capacitance current, the zero sequence open delta voltage that obtains described voltage transformer secondary side, obtains measuring zero sequence open delta voltage;
Step (14), according to described measurement capacitance current, measurement zero sequence open delta voltage and secondary side slotted line voltage, computing system capacitance current.
2. the system capacitive current measuring method of the electric power system for coal production according to claim 1, it is characterized in that, described step (12) specifically comprises: measure respectively three secondary side line voltages of described voltage transformer secondary side, calculate the mean value of three secondary side line voltages as secondary side slotted line voltage.
3. the system capacitive current measuring method of the electric power system for coal production according to claim 1, it is characterized in that, carrying out between described step (11) and step (12), also comprise: measure the zero sequence open delta voltage of described voltage transformer secondary side as opening voltage.
4. the system capacitive current measuring method of the electric power system for coal production according to claim 3, is characterized in that, if described opening voltage is greater than default load balance threshold value, described step (13) specifically comprises:
The isolation switch of described measurement electric capacity and the first primary side phase line closes, obtain the current measurement value of described current measuring device as the first capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the first zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the first primary side phase line, wait for described measurement capacitor discharge;
The isolation switch of described measurement electric capacity and the second primary side phase line closes, obtain the current measurement value of described current measuring device as the second capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the second zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the second primary side phase line, wait for described measurement capacitor discharge;
The isolation switch of described measurement electric capacity and the 3rd primary side phase line closes, obtain the current measurement value of described current measuring device as the 3rd capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as the 3rd zero sequence open delta voltage;
Disconnect the isolation switch of described measurement electric capacity and the 3rd primary side phase line;
Described measurement capacitance current is the mean value of described the first capacitance current, the second capacitance current and the 3rd capacitance current, and described measurement zero sequence open delta voltage is the mean value of described the first zero sequence open delta voltage, the second zero sequence open delta voltage and the 3rd zero sequence open delta voltage.
5. the system capacitive current measuring method of the electric power system for coal production according to claim 3, is characterized in that, if described opening voltage is less than or equal to default load balance threshold value, described step (13) specifically comprises:
The isolation switch of described measurement electric capacity and one of them primary side phase line closes, obtain the current measurement value of described current measuring device as measuring capacitance current, measure the zero sequence open delta voltage of described voltage transformer secondary side as measuring zero sequence open delta voltage.
6. the system capacitive current measuring method of the electric power system for coal production according to claim 1, is characterized in that, described step (14) specifically comprises:
Calculate described system capacitive current=(secondary side slotted line voltage/measurement zero sequence open delta voltage) * measurement capacitance current.
7. the system capacitive current measuring method of the electric power system for coal production according to claim 1, it is characterized in that, carrying out between described step (11) and step (12), also comprise: exit the arc suppression coil being connected with electric power system, disconnect the load on the zero sequence open delta voltage of described voltage transformer secondary side.
8. the system capacitive current measuring method of the electric power system for coal production according to claim 7, is characterized in that, the load on the zero sequence open delta voltage of described voltage transformer secondary side is secondary resonance eliminator.
9. the system capacitive current measuring method of the electric power system for coal production according to claim 1, is characterized in that, three primary side phase lines of described bus are also connected with isolation switch by disconnector, isolating switch respectively successively.
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| CN109888732A (en) * | 2018-01-09 | 2019-06-14 | 广东电网有限责任公司电力调度控制中心 | A kind of generator stator ground load inverse time-lag protection method based on earth-fault current |
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