A kind of method and device thereof of measuring high tension voltage with current method
Technical field
The invention belongs to the high-tension measurement field, relate in particular to the method and apparatus that a kind of size of current that flows through its given load by detection is measured high tension voltage.
Background technology
At present, state, inside and outside electric system mainly contain two kinds of methods to the sampling of voltage measurement, electric energy metrical, monitoring or the needed high-voltage signal of protective device of high-voltage system:
(1) adopt electromagnetic potential transformer (being called for short PT, down together) high-voltage variable to be changed into the low-voltage (100 or 100/ of standard
), again it being carried out voltage measurement, carries out electric energy metrical for protective device use or access electric energy meter, this side has relatively high expectations to the output capacity of mutual inductor;
(2) along with the raising of Automation of Electric Systems degree and the extensive application of Microcomputer Protection mode; the output capacity of measuring, measuring, monitor, voltage sensor is used in protection is required decline greatly, so the various method and apparatus that utilize optical fiber mutual inductor, electronic mutual inductor, capacitive divider, resitstance voltage divider to carry out voltage sampling occurred.
Above-mentioned two kinds of sampling methods cut both ways:
(1) for electromagnetic potential transformer:
The a.PT volume is big, weight is big;
B. make and operation, use cost height;
C. easy break-down.
Electromagnetic resonance in the electrical network, higher hamonic wave, switching overvoltage threaten all can for the safe operation of PT, become insoluble problem; Simultaneously, the conductor cross-section of PT is very little, belongs to product relatively more fragile in the electric system application element thereof, when resonance or odd harmonic source appear in system, very easily burns PT, influences the safe operation of electric system; And it is higher to consume energy during the PT operation, also is unfavorable for saving energy and reduce the cost.
The material of making PT mainly contains materials such as siliconized plate, copper, steel, transformer oil and epoxy resin, all is non-renewable, indispensable important materials of the national economic development.
How to reduce high pressure measurement device self kwh loss, reduce its volume, energy savings, economical with materials, reduce investment outlay, reduce measuring cost, guarantee the good and environmental-protecting performance of its Electro Magnetic Compatibility, the installation that makes things convenient for product, use, maintenance, all become meter and protected the focus that the industry practitioner is studying always, paying close attention to.
(2) in order to address the above problem, occurred adopting optical fiber mutual inductor, electronic mutual inductor, capacitive divider, resitstance voltage divider to carry out the method for voltage sampling, solved the subproblem that exists with electromagnetic transformer, but because it all is based on the principle of voltage divider: U in measurement
1/ U
2=Z
1/ Z
2(wherein Z is the dividing potential drop impedance) is subjected to all multifactor influences such as stability, distributed capacitance, temperature variation, corona, voltage-to-ground of resistance, and the stability of its measuring accuracy, detected parameters etc. all exists many problems.
In addition, the said goods because:
A. all be to adopt the mode of dividing potential drop to take out voltage;
B. product all is the voltage that can only measure relatively at present;
C. the voltage of measuring relative phase need be equipped with two products simultaneously and just can measure;
D. branch pressure voltage is subjected to the influence of distributed capacitance over the ground bigger, and the measuring error instability can not adapt to the electric system with multiple connection plan form well;
E. unstable properties under the outdoor condition, the trial run effect is undesirable.
So applying of its product is not fully up to expectations.
Summary of the invention
Technical matters to be solved by this invention provides a kind of method and device thereof that is used to measure high tension voltage; it has overcome many drawbacks of using electromagnetic potential transformer to bring; can adapt to electric system well with various connection plan forms; can realize the high tension voltage measurement of the relative phase of three-phase three-wire system or three-phase four-wire system easily; satisfy differential protection; the sample of signal requirement of zero sequence protection device; meet metering; measure; the requirement of monitoring and protection rules; whole device was both energy-conservation; save installing space; save manufacturing materials; can reduce measuring cost significantly again; be convenient to metering; measure; the installation of monitoring or protective device; operation and maintenance; what is more important can improve the safe operation coefficient, improves power supply quality.
Technical scheme of the present invention is: a kind of method with current method measurement high tension voltage is provided, comprises the voltage signal input end of tested voltage end and voltage measurement, metering, monitoring or protective device, it is characterized in that:
(1) has an impedance Z of standard/blocked impedance in tested voltage end parallel connection one
1
(2) current sensor is set, detects and flow through impedance Z one time
1Electric current I
1
(3) by current sensor with I
1Be transformed to current i
2
(4) with current i
2Send into a secondary impedance Z with standard/blocked impedance
2, produce a standard signal u who is proportional to tested voltage at its two ends
2
(5) with u
2Insert the input end of voltage measurement, metering, monitoring or protective device as voltage signal to be measured, carry out usefulness of required measurement, metering, monitoring or protection detection for it with high input impedance.
Above-mentioned current i
2Through sending into voltage measurement, metering, monitoring or protective device again after the high/low pressure isolation.
The present invention also provides a kind of device with current method measurement high tension voltage based on such scheme, the voltage signal input end that comprises tested voltage end and voltage measurement, metering, monitoring or protective device, it is characterized in that: between the voltage signal input end of tested voltage end and voltage measurement, metering, monitoring or protective device, be provided with by comprising that at least one has an impedance of standard/blocked impedance, a secondary impedance with standard/blocked impedance and the high pressure sensor that current sensor constitutes; Wherein, an impedance is connected with the two ends of tested voltage with after the input end of current sensor is connected; The output terminal of its current sensor is in parallel with secondary impedance; The two ends of its current sensor are connected with the voltage signal input end of voltage measurement, metering, monitoring or protective device.
The output terminal of above-mentioned current sensor is connected with the voltage signal input end of voltage measurement, metering, monitoring or protective device through high/low pressure isolated location.
Its high/low pressure isolated location can be photo-electric, optical fiber type, electromagnetic type, gas-insulating type, oil-insulation formula or solid insulation formula spacer assembly.
Its impedance, secondary impedance can be resistive load, capacity load, inductive load or its combination.
Its current sensor is photo-electric current sensor, fibre optic current sensor, electromagnetic type current sensor, micro-transformer of current or penetration type micro-transformer of current, and its primary side current input terminal is serially connected between an impedance and the tested voltage end; Perhaps, one of impedance link passes the penetration type micro-transformer of current; Its secondary current output terminal is connected with the voltage signal input end of voltage measurement, metering, monitoring or protective device.
Its voltage measurement, metering, monitoring or protective device are voltage table, digital voltmeter, electric power meter, power system monitor or protective device.
Its electric power meter can be mechanical power energy meter, electronic electric energy meter, penetration type electric energy meter or electronic metering module.
Compared with the prior art, advantage of the present invention is:
1. the employing current method is measured high tension voltage, has solved the electromagnetic resonance that electromagnetic transformer exists, higher hamonic wave, switching overvoltage to problems such as safe operation threaten, satisfies the requirement of metering, measurement, monitoring and protection fully;
2. avoided adopting the common voltage sensor of partial pressure type measuring method to be subjected to the influence of distributed capacitance over the ground bigger, the measuring error deviation differs in the electric system of different topology structure, can not adapt to the problem of the electric system with multiple connection plan form well;
3. can realize the high tension voltage measurement of the relative phase of three-phase three-wire system or three-phase four-wire system easily;
4. both can adopt the conventional mode of connection to satisfy the sample of signal requirement of zero sequence protection device, can form the open delta mode of connection again, satisfy the sample of signal requirement of differential protection;
5. the needs that can adapt to grid automation can provide and satisfy the multiple required voltage signal of metering, measurement, monitoring or protection system simultaneously, it is measured oversimplify;
Its sampling mode not only energy-conservation, save installing space, save manufacturing materials, but also can reduce measuring cost significantly, environmental protection is convenient to measure, the mounting, commissioning and maintenance of measurement or protective device, has played key effect to improving power supply quality.
Description of drawings
Fig. 1 is an electrical block diagram of the present invention;
Fig. 2 is the circuit diagram of one of embodiment;
Fig. 3 is two the circuit diagram of embodiment;
Fig. 4 is three the circuit diagram of embodiment;
Fig. 5,6,7 is the outside drawing of the product of above-mentioned three embodiment.
1,2 is the high voltage measuring terminals among the figure, and 3,4 is the voltage signal output end of high pressure sensor, Z
1, Z
1', Z
1" being first impedance, CS, CS ', CS " is current sensor, Z
2, Z
2', Z
2" be second impedance.
Embodiment
The method of the present invention's measurement high tension voltage is:
(1) has an impedance Z of standard/blocked impedance in tested voltage end parallel connection one
1
(2) current sensor is set, detects and flow through impedance Z one time
1Electric current I
1
(3) by current sensor with I
1Be transformed to current i
2
(4) with current i
2Send into a secondary impedance Z with standard/blocked impedance
2, produce a standard signal u who is proportional to tested voltage at its two ends
2
(5) with u
2Insert the input end of voltage measurement, metering, monitoring or protective device as voltage signal to be measured, carry out usefulness of required measurement, metering, monitoring or protection detection for it with high input impedance.
Above-mentioned current i
2Through sending into voltage measurement, metering, monitoring or protective device again after the high/low pressure isolation.
By formula, then the present invention's measuring principle can be expressed as follows:
Setting has an impedance Z of standard/blocked impedance at tested voltage U two ends
1, then have:
U/Z
1=I
1
Wherein, the tested voltage of U-, Z
1-impedance, I
1-flow through the electric current in the impedance one time;
Electric current I
1(for example: primary side current transformer) forms electric current, i at its secondary side by current sensor
2Flow through the secondary impedance Z that is attempted by the current sensor output terminal
2, form secondary voltage u
2, u
2Insert the input port of voltage table, digital voltmeter, electric energy metrical, electric power supervisory control or protective device.
U and u
2Ratio k constituted the no-load voltage ratio of current sensor:
k=U/u
2
Wherein, the no-load voltage ratio of k-current sensor, the tested voltage of U-, u
2-secondary voltage;
U then
2* k is tested voltage.
The circuit structure that can realize said method as shown in Figure 1.
Among Fig. 1, between the voltage signal input end 3,4 of tested voltage end 1,2 and voltage measurement, metering, monitoring or protective device, be provided with by comprising a impedance Z at least with standard/blocked impedance
1, secondary impedance Z
2High pressure sensor with a current sensor CS formation; Wherein, an impedance is with after the input end of current sensor is connected; be connected with the two ends of tested voltage, the output terminal of its current sensor is in parallel with secondary impedance, and the two ends of its current sensor are connected with the voltage signal input end of voltage measurement, metering, monitoring or protective device.
Its impedance, secondary impedance are resistive load, capacity load, inductive load or its combination.
Current sensor is photo-electric current sensor, fibre optic current sensor, electromagnetic type current sensor, micro-transformer of current or penetration type micro-transformer of current, and its primary side current input terminal is serially connected between an impedance and the tested voltage end; Perhaps, one of impedance link passes the penetration type micro-transformer of current; Its secondary current output terminal is connected with the voltage signal input end of voltage measurement, metering, monitoring or protective device.
Because the current sensor that is adopted does not have iron core; adopt it to provide guard signal for the protection loop; its I/O ratio is entirely linearity, can solve the full sensitivity that brings of magnetic and reduce and caused protection loop misoperation phenomenon, and can save a large amount of aforementioned valuable or non-renewable materials.
Because the voltage signal of its output is the voltage signal of standard class; can mate with existing metering, measurement, monitoring or protective device easily; need not to carry out again conversion, help simplifying line construction and cut down the number of intermediate links the precision of raising metering, measurement, monitoring and protection.
Above-mentioned voltage measurement, metering, monitoring or protective device can be voltage table, digital voltmeter, electric power meter, power system monitor or protective device; its electric power meter can be mechanical power energy meter, electronic electric energy meter, penetration type electric energy meter or electronic metering module; it is the known technology of this area, no longer narrates at this.
Because it is identical that the symbol of each device or parts among the figure, numbering, naming method and the drawing of existing change, distribution system are accustomed to, concrete implication those skilled in the art of its each letter, symbol is appreciated that no longer carefully fully and states.
Embodiment 1:
The single-phase high voltage circuit is carried out voltage measurement:
Adopt circuit shown in Figure 2, the output terminal of current sensor CS is isolated the back through high/low pressure and is connected with the voltage signal input end 3,4 of voltage measurement, metering or protective device.
Its high/low pressure isolated location can be selected photo-electric, optical fiber type, electromagnetic type, gas-insulating type, oil-insulation formula or solid insulation formula spacer assembly for use.
Adopt high/low pressure isolated location that the voltage signal of being gathered is handled, can satisfy requirements such as the requirement of high and low pressure isolation, electromagnetic screen (electromagnetic compatibility), the ratio that satisfies the accuracy of measuring, angular difference and voltage protection loop sampled signal simultaneously.
Because high/low pressure is isolated into prior art, no longer narrates at this.
All the other same Fig. 1.
Embodiment 2:
The three-phase three-wire system circuit is carried out phase voltage to be measured:
Adopt circuit shown in Figure 3, use two groups of high pressure sensors be connected to the A-B of power supply, B-C mutually between, carry out the measurement of voltage between phases, and with the voltage detection signal of V-v mode of connection outputting standard grade.
For drawing succinct, not shown high/low pressure isolated location (down with).
All the other are with Fig. 1 or embodiment 1.
Embodiment 3:
The three-phase three-wire system circuit is carried out voltage measurement:
Adopt circuit shown in Figure 4, use three groups of high pressure sensors to be connected between the A of power supply, B, C and its central point O, carry out the measurement of voltage, and be connected with voltage measurement, metering, monitoring or protective device with the Y-y mode of connection.
All the other are with Fig. 1 or embodiment 1.
In addition, can also adopt the mode of connection of zero sequence or open delta to be connected,, no longer narrate at this because the above-mentioned mode of connection, principle of work and high pressure protector are prior art with protective device.
That Fig. 5,6,7 is respectively is single-phase, the outside drawing of the product of the three-phase V-v mode of connection and the three-phase Y-y mode of connection.
By shown in Fig. 5,6,7 as seen, adopt technique scheme, parts overall package such as first and second impedance, current transformer and high/low pressure isolated location can be become one, design, the installation and maintenance of product both be convenient to, can form tandem product standardized, that have unified installation dimension again, the popularization, mounting, commissioning and maintenance of giving product are with bringing very big facility.
Because the present invention adopts current method to measure high tension voltage; it has overcome many drawbacks of using electromagnetic potential transformer to bring; can adapt to electric system well with various connection plan forms; can realize the high tension voltage measurement of the relative phase of three-phase three-wire system or three-phase four-wire system easily; satisfied the sample of signal requirement of differential protection and zero sequence protection device; meet metering; measure; the requirement of monitoring and protection rules; whole device was both energy-conservation; save installing space; save manufacturing materials; can reduce measuring cost significantly again, be convenient to metering; measure; the installation of monitoring or protective device; operation and maintenance.
The present invention can be widely used in measurement, the electric energy metrical of high tension voltage, or provides high-tension electricity such as needed voltage signal to press fields of measurement for monitoring, the protective device of electric system.