Background technology
Electric energy as important energy source easy to use, that high-quality is clean, is the important motivity of the national economic development, is related to national economy, and is closely bound up with people's lives and industrial and agricultural production.
Along with improving constantly of expanding economy and living standards of the people, impel and send out, constantly increase for, power consumption; The dealing of electric energy and how to measure and calculate its value seems very important day by day.
Present electric energy metrical mainly carries out according to the measured continuous data of electric power meter; Do the gage work of electric energy well, correctly measure the use amount of electric weight, make metering numerical value more accurately, fair, just, directly have influence on send out, for, electricity consumption three parts's economic interests.
High-voltage electric-energy meter is the specialized equipment of electric energy metrical, it be connect to send out, for, the tripartite imperative equipment of electricity consumption.Because its application surface is wide in a large number, except that require safety and reliability stable, improve metering performance, reduce the self electric quantity loss, reduce volume, save take up an area of space, energy savings, economical with materials, reduce investment outlay, reduce measuring cost, Electro Magnetic Compatibility is good and environmental protection, installation, use, easy to maintenance, the focus of become practitioner's research, paying close attention to.
At present, the needed high-voltage signal of the measuring apparatus of state, inside and outside high voltage electric energy normally adopts voltage transformer (VT) high-voltage variable to be changed into the low-voltage (100V or 100/ of standard
V), adopt current transformer to change big electrorheological the little electric current (5A or 1A) of standard into, the more above-mentioned little electric current of standard low-voltage, standard is sent into corresponding measuring apparatus, to finish corresponding gage work.
Electromagnetic current transducer (is called for short CT, down together) volume is big, weight is big, cost is high, iron core is easily saturated, and electromagnetic potential transformer (is called for short PT, down together) except that above-mentioned shortcoming, electromagnetic resonance, higher hamonic wave, switching overvoltage threaten all can for the safe operation of voltage transformer (VT), 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 transmission, the metering loss of energy-conservation and minimizing electric energy.
The material of making PT, CT mainly contains materials such as siliconized plate, copper, steel, transformer oil and epoxy resin, all are 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.
Open day be April 19 nineteen ninety-five, and Granted publication number is to disclose a kind of " substation transformer high pressure measurement device " in the Chinese invention patent of CN 1051373C, it is characterized in that described measuring apparatus do not have high-voltage mutual inductor; Sampling current is taken from the end of substation transformer high-tension coil: sampling voltage is taken from the adjacent tap of substation transformer high pressure winding neutral end.Different with the conventional high-tension measuring apparatus, its electric energy metrical sample of signal point is not the head end that is connected on substation transformer high pressure winding, but be connected on its neutral end, because the singularity of neutral point, current sampling loop interphase potential difference is zero, voltage sampling is directly drawn from tap, makes it can save high voltage potential transformer and high-tension current inductor, but there is following problem:
1. when transformer operated in zero load, different loads or full-load run state, the iron core magnetic flux density of transformer was inequality, and the voltage error of taking-up changes with the variation of load, can not satisfy the requirement of high pressure measurement precision;
2. require the capacity of output higher, the open circuit loss of transformer is had certain influence, be unfavorable for the Transformer Economic operation;
3. high/low hydraulic circuit fails to realize electromagnetic isolation, does not meet the requirement of existing security of operation rules, has potential safety hazard;
4. metering can't be provided simultaneously, measure or the required signal in protection loop, high-tension measurement or protection loop still need can not realize cancellation voltage transformer (VT) truly by the high-voltage mutual inductor number of winning the confidence;
5. when circuit generation singlephase earth fault, transformer neutral point voltage raises, and very easily punctures or burns metering electric energy meter;
6. can only be applicable to the substation transformer of star connection, applicable surface is narrower.
Summary of the invention
Technical matters to be solved by this invention provides a kind of can adaptation the metering; measure or protect the high voltage signal sampling method that needs; it can realize height truly; low pressure is isolated; meet existing operation safety; metering; measure and protect the requirement of rules; Electro Magnetic Compatibility (also claiming electromagnetic wave shielding) is good; can not influence the running technology index of transformer; the needs that can adapt to grid automation; can provide and satisfy metering simultaneously; the electric energy that the multiple precision of measurement or protection system needs; voltage or current signal; its sampling mode was both energy-conservation; save installing space; save manufacturing materials; can reduce measuring cost significantly again; metering is convenient in environmental protection; the installation of measurement or protective device; operation and maintenance.
Technical scheme of the present invention is: a kind of high voltage signal sampling method that can adapt to metering, measure or protect needs is provided, comprise current sampling and voltage sampling, it is characterized in that: the primary winding side in transformer inside is provided with small electric current sensor, takes out a high-tension current signal in proportion from the former limit or the end of incoming cables of transformer; In the winding of each phase of the inner primary winding of transformer, corresponding potential coil is set, takes out a high tension voltage signal in proportion from the former limit of transformer; The high tension voltage signal that each phase is taken out carries out electromagnetism/voltage isolation, compensation respectively; With the current signal got and through isolation, the compensated voltage signal, with the V-v mode of connection or the Y-y mode of connection send into high-voltage electric energy measurement, measuring unit carries out metering, the measurement of high voltage electric energy; Perhaps, send into protective device, for it provides protection required signal with the zero sequence or the open delta mode of connection.
Wherein, above-mentioned small electric current sensor is penetration type or open-core type current transformer.
Its described potential coil has tap changer, can regulate its output voltage in ± 5% scope, the output voltage of the output voltage of potential coil and transformer is regulated carry out synchronously and is complementary.
Above-mentioned electromagnetism/voltage isolation, compensation realize by isolation/error compensator; Its described isolation/error compensator is isolating transformer, capacitance type potential transformer, miniature voltage transformer (VT), electronic type voltage transformer or resitstance voltage divider.
Perhaps, its described isolation/error compensator adjustable compensation unit of comprising isolating transformer, capacitance type potential transformer, miniature voltage transformer (VT), electronic type voltage transformer, resitstance voltage divider and being connected on its output terminal constitutes.
Its described adjustable compensation unit is made of adjustable building-out capacitor, compensating inductance and compensating resistance, its building-out capacitor is attempted by the two ends of isolating transformer output terminal, is connected on the two ends of isolating transformer output terminal behind compensating inductance and the compensating resistance serial or parallel connection.
Its described isolating transformer primary coil also has tap changer, it is through the tap changer respectively corresponding connection of change-over switch with the transformer potential coil, can in ± 5% scope, regulate, the output voltage of the output voltage of isolating transformer and transformer be regulated carry out synchronously and be complementary its output voltage.
Above-mentioned current signal or through isolation, the compensated voltage signal is for follow-up metering, measurement or protection module, unit or install required rated current or normalized current signal or normal voltage signal that voltage is complementary.
Above-mentioned high-voltage electric energy measurement unit is mechanical power energy meter, electronic electric energy meter, penetration type electric energy meter or electronic metering module; Above-mentioned high-tension measurement unit is electromagnetic type or digital high tension voltage/reometer.
Compared with the prior art, advantage of the present invention is:
1. adopt small electric current sensor and be arranged on potential coil on the transformer first siding ring as metering, measure or the signal in protection loop provides the source, conventional split stand alone type CT, PT have been saved, dwindled the volume of high voltage signal sampling device greatly, made that whole sampler is arranged on transformer inside becomes possibility;
2. adopt small electric current sensor to provide current signal for metering, measurement or protection loop, its I/O ratio is entirely linearity, can improve metering performance, for the protection loop provides current signal, can solve the protection loop that magnetic saturation brings and be failure to actuate or the misoperation phenomenon with hollow mutual inductor;
3. adopt isolation/error compensator 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;
4. will be independently high pressure P T make into for will isolate/error compensator is connected in parallel on tap place of transformer potential coil, when system resonance, odd harmonic source occur or switching overvoltage occurs, the coil of transformer has played protective effect, avoided burning the generation of PT fault, help improving the safe reliability of Operation of Electric Systems, and can save a large amount of non-ferrous metals and manufacturing materials;
5. by actual measurement; former operational factor to transformer behind the employing said method produces any influence hardly; this measurement that just means high-tension current, voltage, electric energy is the loss electric energy hardly, has saved the energy, has reduced the operating cost in metering, measurement and protection loop.
Embodiment
Among Fig. 1, the present invention's specific implementation method is:
First siding ring in transformer inside is provided with small electric current sensor, takes out a high-tension current signal in proportion from the former limit or the end of incoming cables of transformer; In the winding of each phase of the inner primary winding of transformer, corresponding potential coil is set, takes out a high tension voltage signal in proportion from the former limit of transformer; The high tension voltage signal that each phase is taken out carries out electromagnetism/voltage isolation, compensation respectively; With the current signal got and through isolation, the compensated voltage signal; with the V-v mode of connection or the Y-y mode of connection send into high-voltage electric energy measurement, measuring unit carries out metering, the measurement of high voltage electric energy; or send into protective device with the zero sequence or the open delta mode of connection, for it provides protection required signal.
Among Fig. 2, first siding ring or its end of incoming cables in transformer 1 inside are provided with small electric current sensor 2, corresponding potential coil 3 is set in the winding of each phase of transformer primary winding, and the high tension voltage signal that each phase is taken out carries out electromagnetism/voltage isolation, compensation respectively through isolation/error compensator 4; With current signal and through isolation, the compensated voltage signal is sent into high-voltage electric energy measurement, measurement mechanism 5 measures; Perhaps, sending into the high pressure protector (not shown) provides protection required signal for it.
Its small electric current sensor can be penetration type or open-core type current transformer;
Its isolation/error compensator is isolating transformer, capacitance type potential transformer, miniature voltage transformer (VT), electronic type voltage transformer or resitstance voltage divider; Output terminal at isolating transformer, capacitance type potential transformer, miniature voltage transformer (VT), electronic type voltage transformer or resitstance voltage divider can be provided with the adjustable compensation unit; The adjustable compensation unit is made of adjustable building-out capacitor, compensating inductance and compensating resistance, its building-out capacitor is attempted by the two ends of isolation voltage sensor output terminal, is connected on the two ends of isolation voltage sensor output terminal behind compensating inductance and the compensating resistance serial or parallel connection.
Its high-voltage electric energy measurement unit can be mechanical power energy meter, electronic electric energy meter, penetration type electric energy meter or electronic metering module; Its high-tension measurement unit can be electromagnetic type or digital high tension voltage/reometer.
The present invention will be further described below in conjunction with drawings and Examples.
Embodiment 1:
The high pressure measurement signal sampling method of uniline transformer:
Adopt the method for Fig. 1 and the annexation of Fig. 3, on the lead-in wire of the first siding ring 1B of transformer or its end of incoming cables small electric current sensor CT is set, corresponding potential coil FY is set in the transformer primary winding winding, and the high-tension current that each phase is taken out, voltage signal carry out electromagnetism/voltage isolation, compensation respectively through isolation/error compensator; With current signal with through the sub-U of voltage, current input terminal that isolates, the compensated voltage signal is sent into high-voltage electric-energy meter 5
A, U
O, I
HAnd I
L, measure.
Wherein, isolation/error compensator adopts isolating transformer GLB and is connected on the adjustable compensation unit formation of its output terminal, its adjustable compensation unit is made of adjustable building-out capacitor, compensating inductance and compensating resistance, its building-out capacitor is attempted by the two ends of isolating transformer output terminal, is attempted by the two ends of isolating transformer output terminal behind compensating inductance and the compensating resistance serial or parallel connection.
The annexation of each element is not limited to the annexation shown in the figure in the adjustable compensation unit, and the needs according to the reality compensation can also have other connected modes, and the concrete numerical value of each compensating element, is decided as required.
If the isolation of isolating transformer/error compensation effect can satisfy the needs that use, then the adjustable compensation unit also can be cancelled to save manufacturing cost.
Owing to the primary coil of transformer is used as voltage divider, by the sampling of turn ratio dividing potential drop, U1: U2=N1: N2.Consider the problem of traceability, get 500V voltage at the primary coil of transformer, isolation/the error compensator that inserts 500V/100V in parallel, isolation/error compensator is made up of voltage transformer (VT) (electromagnetic compensation), building-out capacitor (adjustable), the compensation electricity group original papers such as (adjustable) of low capacity, with the accuracy requirement (ratio, angular difference) that satisfies high-voltage electric energy measurement, current measurement.
In order to eliminate the influence in electric field, magnetic field, isolation/error compensator will be handled through electromagnetic screen, solves electromagnetic compatibility problem with the interference of getting rid of electric field, magnetic field.
It is in order to finish following 4 work that isolation/error compensator is set:
A, high and low pressure are isolated, and solve the safe operation problem;
B, electromagnetic screen solve electromagnetic compatibility problem;
C, voltage compensator satisfy the metering performance requirement of ratio, angular difference, make metering satisfy accuracy requirement;
D, provide sampled signal for the voltage protection loop.
Compare with common voltage transformer (VT), this isolation/error compensator volume is very little, consumes that material is few, self power consumption is extremely low.When surge voltage, dash current or resonance current, voltage appearred in system, the winding of transformer (being equivalent to a big telefault) had protective effect to isolation/error compensator, and follow-up metering, measure portion can avoid being affected and endangering.
Potential coil has tap changer 1,2,3, can in ± 5% scope, regulate its output voltage, the isolating transformer primary coil also have tap changer 1 ', 2 ', 3 ', can in ± 5% scope, regulate equally its output voltage, between the tap changer of the tap changer of potential coil and isolating transformer primary coil, be connected one switch switch (for drawing succinct, do not draw among the figure, down together), by regulating the gear of change-over switch, the output voltage of the input voltage of the output voltage of potential coil and isolating transformer and transformer is regulated carry out synchronously and be complementary, the output voltage stabilization that guarantees isolating transformer needed (for example: 500V ± 5%) in the scope.
By suitable isolation/error compensator output valve is set; current signal or process are isolated; the compensated voltage signal is and follow-up metering; measure or protection module; unit or install required rated current or normalized current signal or normal voltage signal that voltage is complementary; as meet China's current metering; measure the 5A of rules; 1A; 10mA; metered voltage/the current signal of standard such as 100V or 10mV also can adopt the 22.5mV relevant with electronic type voltage/current transformer in the relevant criterion that meets American National Standards Institute (ANSI) (ANSI) or International Organization for Standardization or International Electrotechnical Commission (IEC); 150mV; 200mV; 225mV; 1V; standard figures such as 2V or 4V.
Because its voltage, current signal are voltage, the current signal of standard; can mate with existing metering, measurement or protection module, unit or device easily; need not to carry out again conversion; help simplifying line construction and cut down the number of intermediate links the precision of improve metering, measuring and protect.
According to the relevant criterion and the rules of China's current, the mode of the current measurement that small electric current sensor provides can have two kinds:
(a) provide the electric current 5A of standard, handle, for electric energy meter metering electric energy provides normalized current according to current transformer;
(b) provide the electric current 10mA of standard, directly the supply of electrical energy metering module carries out high-voltage electric energy measurement or current measurement.
Equally, the mode of the voltage measurement that provides of isolation/error compensator can also have two kinds:
(a) provide the low-voltage 100V of standard, handle, for electric energy meter metering electric energy provides normal voltage according to voltage transformer (VT);
(b) provide the voltage 10mV of standard, directly the supply of electrical energy metering module carries out high-voltage electric energy measurement or voltage measurement.
Its small electric current sensor is penetration type or open-core type current transformer, particularly, its small electric current sensor can selective light fiber current sensor (OCT), hollow current sensor, Ruo Gaofusiji (Rogowski) coil, electronic current mutual inductor or photoelectric current inductor.
Because the current sensor device of above-mentioned form 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 protection loop misoperation phenomenon that the full sensitivity that brings of magnetic reduces and causes; and CT does not have coil one time; current return does not almost have power consumption, can save a large amount of valuable or non-renewable materials, and wherein copper material can be saved about 99.8%, silicon steel agreement that contracts a film or TV play to an actor or actress 98%, resin or transformer oil and save 100% and a large amount of steel.
Its isolating transformer can also adopt voltage sensor devices such as voltage transformer (VT), capacitance type potential transformer, miniature voltage transformer (VT), electronic type voltage transformer or resitstance voltage divider to replace.
After adopting above-mentioned voltage sensor device to substitute high-voltage mutual inductor (PT), the power consumption that is connected in parallel on the loop on the voltage of 5% after the transformer potential coil dividing potential drop is extremely low, through actual measurement the open circuit loss of transformer almost there is not influence, can ignore, simultaneously, can save various noble metals and non-renewable manufactured materials in a large number, wherein copper material can be saved about 95%, silicon steel agreement that contracts a film or TV play to an actor or actress 92%, resin or transformer oil and save 100% and a large amount of steel.
Its high-voltage electric energy measurement unit can be mechanical power energy meter, electronic electric energy meter, penetration type electric energy meter or electronic metering module; Its high-tension measurement unit can be electromagnetic type or digital high tension voltage/reometer, and this is the known technology of this area, no longer narrates at this.
After taking above measure, the overall energy-conservation of high-voltage electric-energy meter reaches 90%, save manufactured materials 85%, each stoichiometric point can be saved nearly ten thousand yuan of investments, and annual each stoichiometric point can be saved 1000~2000 yuan of the own loss electricity charge (10KV electric pressure circuit) or 1500~3800 yuan (35KV electric pressure circuit).
Because it is identical that the symbol of each device or parts among the figure, numbering, naming method and the drawing of existing transformation and 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 2:
Adopt sampler of this sampling method and being connected of high pressure protector:
Adopt the annexation of Fig. 4; the initial and end end that is arranged at the output terminal of the current transformer 2 on the three-phase supply and is connected in the output terminal of the isolation/error compensator 4 on the potential coil 3 of transformer three-phase first siding ring is connected in series respectively successively; form the open-delta mode of connection; its voltage/current signals is sent into protective device 6, for it provides running protection required signal.
In like manner, above-mentioned components and parts also can adopt the zero sequence mode of connection to be connected with protective device.
Because the above-mentioned mode of connection, principle of work and high pressure protector are prior art, no longer narrate at this.
Succinct for drawing, shunting switch does not also draw among the figure.
All the other are with embodiment 1.
Embodiment 3:
The high pressure measurement signal sampling method of three-phase three-wire system transformer:
Transformer for three-phase three-wire system, can adopt annexation shown in Figure 5, use corresponding respectively A, the C that is arranged on transformer of two groups of small electric current sensors, two component line ball circles and two isolation/error compensators to go up mutually, the output terminal employing V-v mode of connection of small electric current sensor and isolation/error compensator and corresponding connection of voltage, current input terminal of three-phase electric energy metering module, the output terminal of electric energy metrical module is connected with display unit 7.
The purpose that display unit is set is with the measurement data teletransmission, as long as the electric energy metrical module is carried out corresponding insulation and electromagnetic barrier processing, satisfies the associated safety technical requirement of transformer, and the electric energy metrical module can be arranged in the housing of transformer fully.
Because data remote and be shown as prior art is no longer narrated at this.
All the other are with embodiment 1.
Embodiment 4:
The high pressure measurement signal sampling method of three-phase four-wire system transformer:
Transformer for three-phase four-wire system, can adopt annexation shown in Figure 6, with three small electric current sensors, three component line ball circles and three corresponding respectively being arranged on the three-phase of transformer of isolation/error compensator, the output terminal employing Y-y mode of connection of small electric current sensor and isolation/error compensator and corresponding connection of voltage, current input terminal of three-phase electric energy meter.
All the other are with embodiment 1.
The present invention can be widely used in the electric energy metrical field of the single-phase or three-phase transformer of various electric pressures and specification.