CN101173966A - Zero voltage drop digital optoelectronic metering installation - Google Patents
Zero voltage drop digital optoelectronic metering installation Download PDFInfo
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- CN101173966A CN101173966A CNA2007100535251A CN200710053525A CN101173966A CN 101173966 A CN101173966 A CN 101173966A CN A2007100535251 A CNA2007100535251 A CN A2007100535251A CN 200710053525 A CN200710053525 A CN 200710053525A CN 101173966 A CN101173966 A CN 101173966A
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Abstract
The invention relates to an electric energy metering device, comprising a transmitter, a transmitting terminal DC power supply, an optical cable, a receiver, a watt-hour meter and a receiving end DC power supply. The invention is characterized in that analog signal is converted to digital optical signal by means of secondary signal transmission of a voltage transformer, so the voltage drop of secondary signal transmission of a voltage transformer is avoided. The invention has the advantages that secondary voltage signal output by voltage transformer is converted into digital optical signal and transmitted to a control cabinet, enabling zero voltage drop during the transmission of secondary analog voltage signal of the voltage transformer, thereby reducing overall error and improving accuracy of the electric energy metering.
Description
Technical field
The present invention relates to a kind of electric power meter, specifically, thereby relate to a kind of pressure drop of adopting in the digital optical signal transmission voltage mutual inductor secondary singal elimination voltage transformer (VT) signals transmission, reduce the electric power meter of total errors of electric energy countings in the present electric system day-to-day operation.
Background technology
In the day-to-day operation of electric system, should guarantee the accuracy of electric energy metrical, so that reasonably protect power department and user both sides' legitimate rights and interests.Therefore the error of electric energy metrical should be in the de jure standards scope.
Stipulate among the Electricity Department electric power meter inspection procedure SD109-83: I class electric power meter, its voltage transformer secondary loop pressure drop should not surpass 0.25% of rated secondary voltage; II class and III class electric power meter, this voltage should not surpass 0.5% of rated secondary voltage.
The composition error of electric energy metrical is made up of error, the error of current transformer (CT), the error of watt-hour meter, the caused error in dipping of voltage transformer secondary lead pressure drop of voltage transformer (VT) (PT).According to the result of many places electrical network generaI investigation test, in these four errors, the error in dipping that the pressure drop of voltage transformer secondary lead causes is maximum often.
Cause the excessive reason of voltage transformer secondary lead pressure drop to be: because the voltage input signal of each feeder line electric energy meter of transformer station generally is the PT signal on the shared same group of bus, the secondary singal line between from PT to the electric energy meter is longer.In the high-voltage electric-energy meter of electric substation and big-and-middle-sized electricity consumer, need the stube cable line of tens of rice even hundreds of rice between PT secondary connection terminal and the electric energy meter.When the sectional area of lead hour, the resistance of long lead is just more considerable.In addition, the centre is connected to high-speed switch, protective tube, adds secondary connection terminal reasons such as metal partial oxidation loosening and the protective tube two ends and causes the secondary connection impedance bigger.On the long like this stube cable line with big resistance, if the table meter that the PT secondary circuit is inserted, protective relaying device and other load are bigger, then bigger load current will cause bigger secondary circuit voltage drop.
The voltage transformer secondary conductor resistance is excessive, and the pressure drop of secondary lead is excessive, and its direct result is to cause few meter generated energy, delivery, power consumption, so that collects charges for electricity less, causes a delivery imbalance, line loss negative etc. to occur.Existing solution has:
1) the simplest with common method is the mutual device sense of the overstriking voltage secondary cross section that is connected lead, reduces the length that secondary connects lead, and reduces each contact contact resistance.The shortcoming of this method is: even lead is thick again, can not solve the problem that contact resistance and conductor resistance bring.
2) the special-purpose secondary circuit of installing watt-hour meter.Adopt special-purpose measurement loop, comprise and adopt special-purpose voltage transformer secondary metering winding, avoid relay protection, measure the influence of loop measurement loop; Adopt special-purpose metering secondary cable and special-purpose switch, fuse and connection terminal etc.But the angle of this measure slave unit configuration has reduced the voltage transformer secondary loop voltage and has fallen, but owing to also there are equipment such as switch, fuse and connection terminal, the PT secondary voltage drop that causes more greatly because of their contact resistance is bigger, is difficult to satisfy 0.25% the requirement that should be not more than its rated secondary voltage is fallen in voltage transformer secondary loop voltage in the I class electric power meter.
3) adopt voltage error compensator to compensate ratio and the angular difference that the pressure drop of secondary lead causes
Its principle is to add a bucking voltage in secondary circuit, in order to compensate ratio and the angular difference that the pressure drop of secondary lead causes.The device that produces this bucking voltage has multiple: fixed value compensation device, current tracking formula compensator, voltage-tracing formula compensator.First kind is utilized autotransformer and phase shifter to compensate ratio and angular difference, makes PT secondary terminals voltage and electric energy meter meter terminal voltage amplitude and phase place equate, thereby reaches the purpose of compensation.Its shortcoming is to be subjected to load effect big, and it is constant or change little operating mode only to be suitable for load, and effect is relatively poor; Second kind is utilized electronic circuit to pass through tracking to the PT secondary loop current, produces a negative impedance that equates with the secondary circuit impedance, make that the equivalence of secondary circuit resulting impedance is zero, thereby pressure drop is zero.Its shortcoming is if the impedance variation of secondary circuit, just can not be from motion tracking.The shortcoming of these class methods is that its compensation effect is difficult to assessment, easily over-compensation, from metering can north source angle, have defective on the principle.
4) adopt electronic electric energy meter.This method can reduce the power that voltage transformer (VT) provides, thereby reduces the electric current on the signal transmssion line, reduces pressure drop.
But above method all can not be eliminated the voltage drop the voltage transformer secondary signals transmission fully on principle, thereby still has error.
Summary of the invention
The electric energy metering error that the present invention causes at the voltage drop that exists in the present voltage transformer secondary signals transmission just, and provide a kind of Zero voltage drop digital optoelectronic metering installation, this device is with the analog voltage signal in-situ digitalization of voltage transformer secondary output, and convert optical signal transmission to the pulpit, be reduced into simulating signal in the pulpit, the input electric energy meter, thereby eliminated the voltage drop in the signals transmission fully, reduce the error of electric energy metrical greatly, improved the precision of metering.
A kind of Zero voltage drop digital optoelectronic metering installation, constitute by emitter, transmitting terminal dc power supply, optical cable, receiving trap, electric energy meter and receiving end dc power supply, emitter converts the voltage transformer secondary output voltage signal to the digital light pulse signal after optical cable transfers to receiving trap, receiving trap converts the digit pulse light signal to voltage signal and imports electric energy meter again, the transmitting terminal dc power supply is powered to emitter, and the receiving end dc power supply is given receiving trap and electric energy meter power supply.
Described emitter is made up of sample circuit, mould/transformation of variables circuit, electro-optical conversion circuit, the input end of sample circuit connects the high voltage signal end of voltage transformer secondary output, the output terminal of sample circuit is connected with the analog-digital converter circuit input end, the analog-digital converter circuit output terminal is connected with the input end of electro-optical conversion circuit, and the output terminal of electro-optical conversion circuit connects optical cable.Sample circuit generally adopts electric resistance partial pressure, and the high voltage signal that voltage transformer secondary is exported is transformed into low voltage signal, the high voltage signal of 100V or 57.7V is transformed into the low voltage signal of 4V; Mould/transformation of variables circuit is transformed into digital signal with the simulation low voltage signal of sample circuit output, and the principle of mould/transformation of variables circuit is more, adopts A/D translation circuit, V/F translation circuit or the PWM translation circuit directly bought from the market; The electro-optical conversion circuit becomes light pulse signal output with the digital signal transition of mould/transformation of variables circuit output, and can the electro-optical conversion circuit directly be buied from the market, if not all rightly please write the electro-optical conversion circuit clearly, and the circuit diagram that draws.
The transmitting terminal dc power supply is taken from the voltage transformer secondary output voltage signal is transformed into by transformer and is inputed to power module behind the 220V again or directly the high voltage signal of voltage transformer secondary output is inputed to power module.
After receiving trap becomes the signal that electric energy meter can receive with the digital light pulse conversion of signals, the input electric energy meter, carry out electric energy metrical, receiving trap is made up of photoelectric conversion circuit, steering D/A conversion circuit, signal conditioning circuit, the photoelectric conversion circuit input end is connected with optical cable, the other end is connected with the input end of steering D/A conversion circuit, and the output terminal of steering D/A conversion circuit is connected with the input end of signal conditioning circuit, and the output terminal of signal conditioning circuit is connected with electric energy meter.Photoelectric conversion circuit adopts the photoelectric conversion circuit of directly buying from the market.The steering D/A conversion circuit adopts the D/A translation circuit of directly buying from the market.Signal conditioning circuit adopts the signal conditioning circuit of directly buying from the market.
Receiving trap and electric energy meter are combined, and become as a whole, constitute an electric energy meter.
Principle of the present invention is:
Port in the output of PT secondary; pass through emitter; convert secondary voltage analog quantity sampling back emission to digital signal on the spot; with light emission module the digital signal of electricity is become light pulse signal; with optical cable the digital light pulse signal is passed to pulpit at a distance from PT by optical cable again; pass through receiving trap in the pulpit then; digital light pulse is become electric digital signal; again behind the steering D/A conversion circuit; draw and the proportional analog voltage signal of PT secondary output voltage, for the usefulness of electric energy meter meter and other control protective device.If electric energy meter also can directly receive electric digital signal or digital light pulse signal through transforming.
Compare with existent method, adopt advantage of the present invention to be:
A. in traditional analog signal transmission device, bigger decay and distortion will take place after by long lead in analog voltage signal, thereby introduce error.To adopt the transmission of digital light pulse signal behind the analog voltage signal in-situ digitalization of PT secondary output, the information that comprises is almost without any decay and distortion, and signal accuracy can be owing to long Distance Transmission is introduced any error.
B. optical signal transmission can not be subjected to the influence of strong electromagnetic on every side, reliability height.Thereby this device might solve the caused variety of problems of PT secondary lead pressure drop, improves the accuracy of metering.
Description of drawings
Fig. 1 is a principle schematic of the present invention.
Among the figure: 1-voltage transformer (VT), 2-emitter, 3-transmitting terminal dc power supply, 4-optical cable, 5-receiving trap, 6-electric energy meter, 7-receiving end dc power supply.
Embodiment
The present invention is made of emitter, transmitting terminal dc power supply, optical cable, receiving trap, electric energy meter and receiving end dc power supply, emitter converts the voltage transformer secondary output voltage signal to the digital light pulse signal after optical cable transfers to receiving trap, receiving trap converts the digit pulse light signal to voltage signal and imports electric energy meter again, the transmitting terminal dc power supply is powered to emitter, and the receiving end dc power supply is given receiving trap and electric energy meter power supply.
Embodiment is:
1. emitter: effect is that the high voltage signal with voltage transformer secondary output is transformed into the corresponding digital light pulse signal.High voltage signal is generally 100V or 57.7V, so emitter partly is made up of sample circuit, mould/transformation of variables circuit, electro-optical conversion circuit etc. usually:
Sample circuit: generally adopt electric resistance partial pressure, the high voltage signal that voltage transformer secondary is exported is transformed into low voltage signal, the high voltage signal of 100V or 57.7V is transformed into the low voltage signal of 4V.
Mould/transformation of variables circuit: the simulation low voltage signal of sample circuit output is transformed into digital signal.The principle of mould/transformation of variables circuit is more, for example can adopt A/D translation circuit, V/F translation circuit or PWM translation circuit etc.
The electro-optical conversion circuit: the digital signal transition of analog-digital converter circuit output is become light pulse signal output, and the electro-optical conversion circuit adopts the electro-optical conversion circuit of directly buying from the market.
2, transmitting terminal dc power supply: effect is to provide work required direct supply to emitter.This power supply can form civil power through conversion behind the power module, but this method is subjected to the influence of mains failure easily.What the present invention adopted is the method for directly obtaining energy from the high voltage signal of voltage transformer secondary output, for example with the high voltage signal of voltage transformer secondary output, be generally and input to power module again after 100V or 57.7V are transformed into 220V by transformer, obtain required power supply.Perhaps the high voltage signal of directly voltage transformer secondary being exported inputs to power module, obtains required dc supply.This method is not subjected to the influence of mains failure, the reliability height.Simultaneously, emitter power consumption of the present invention is extremely low, the required power supply energy that provides and faint.Another method be exactly with civil power by supply power module behind the UPS, the method cost is higher, but has improved the reliability of power supply.
3, optical cable: be used to transmit the receiving trap of the light pulse signal of emitter output to the pulpit.
4, receiving trap: be used for the light pulse signal of optical cable output is transformed into corresponding analog voltage signal.Receiving trap is made up of photoelectric conversion circuit, steering D/A conversion circuit, signal conditioning circuit, the photoelectric conversion circuit input end is connected with optical cable, the other end is connected with the input end of steering D/A conversion circuit, the output terminal of steering D/A conversion circuit is connected with the input end of signal conditioning circuit, and the output terminal of signal conditioning circuit is connected with electric energy meter.Photoelectric conversion circuit: be used for the light pulse signal of optical cable output is transformed into digital electric signal, photoelectric conversion circuit adopts the photoelectric conversion circuit of directly buying from the market.The steering D/A conversion circuit: be used for digital electric signal is transformed into the corresponding simulating voltage signal, the steering D/A conversion circuit adopts the D/A translation circuit of directly buying from the market.Signal conditioning circuit: the amplitude of analog voltage signal is adjusted to needed size, and signal conditioning circuit adopts the signal conditioning circuit of directly buying from the market.
5, electric energy meter: the analog voltage signal of receiving trap output is inputed to electric energy meter, carry out electric energy metrical.The key distinction of this electric energy meter and general existing electric energy meter is: the one, and existing electric energy meter generally is to obtain working power from the high voltage signal that voltage transformer secondary is exported, high voltage signal is generally 100V or 57.7V, consider that this input simulating signal is a weak signal, can not provide electric energy meter and receiving trap required power, so electric energy meter is designed to the power supply external hanging type, promptly provides working power from the external world.The signal that difference in addition is to import electric energy meter is a weak signal, and for example 4V is different from the voltage input of the 100V or the 57.7V of existing electric energy meter.
In addition, also receiving trap can be designed to combine, then the digital light pulse signal of optical cable output can be directly inputted into electric energy meter with electric energy meter.If electric energy meter can directly receive electric impulse signal, receiving trap can remove the steering D/A conversion circuit, is reduced to photoelectric conversion circuit and signal conditioning circuit, combines with electric energy meter, thereby improves the integrated level and the reliability of device involved in the present invention.
6, receiving end dc power supply: the interchange or the direct current 220V power conversion of pulpit are become receiving trap and the required direct supply of electric energy meter work.
Claims (6)
1. Zero voltage drop digital optoelectronic metering installation, constitute by emitter, transmitting terminal dc power supply, optical cable, receiving trap, electric energy meter and receiving end dc power supply, it is characterized in that: emitter converts the voltage transformer secondary output voltage signal to the digital light pulse signal after optical cable transfers to receiving trap, receiving trap converts the digit pulse light signal to voltage signal and imports electric energy meter again, the transmitting terminal dc power supply is powered to emitter, and the receiving end dc power supply is given receiving trap and electric energy meter power supply.
2. Zero voltage drop digital optoelectronic metering installation according to claim 1, it is characterized in that: described emitter is made up of sample circuit, mould/transformation of variables circuit, electro-optical conversion circuit, the input end of sample circuit connects the high voltage signal end of voltage transformer secondary output, the output terminal of sample circuit is connected with the analog-digital converter circuit input end, the analog-digital converter circuit output terminal is connected with the input end of electro-optical conversion circuit, and the output terminal of electro-optical conversion circuit connects optical cable.
3. Zero voltage drop digital optoelectronic metering installation according to claim 1 and 2 is characterized in that: the mould in the emitter/transformation of variables circuit is A/D translation circuit, V/F translation circuit or PWM translation circuit.
4. Zero voltage drop digital optoelectronic metering installation according to claim 1 is characterized in that: the transmitting terminal dc power supply is taken from the voltage transformer secondary output voltage signal is transformed into by transformer and is inputed to power module behind 22 0V again or directly the high voltage signal of voltage transformer secondary output is inputed to power module.
5. Zero voltage drop digital optoelectronic metering installation according to claim 1, it is characterized in that: receiving trap is made up of photoelectric conversion circuit, steering D/A conversion circuit, signal conditioning circuit, the photoelectric conversion circuit input end is connected with optical cable, the other end is connected with the input end of steering D/A conversion circuit, the output terminal of steering D/A conversion circuit is connected with the input end of signal conditioning circuit, and the output terminal of signal conditioning circuit is connected with electric energy meter.
6. Zero voltage drop digital optoelectronic metering installation according to claim 1 is characterized in that: receiving trap and electric energy meter are combined, and become as a whole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100535251A CN101173966A (en) | 2007-10-11 | 2007-10-11 | Zero voltage drop digital optoelectronic metering installation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100535251A CN101173966A (en) | 2007-10-11 | 2007-10-11 | Zero voltage drop digital optoelectronic metering installation |
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| CN101173966A true CN101173966A (en) | 2008-05-07 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNA2007100535251A Pending CN101173966A (en) | 2007-10-11 | 2007-10-11 | Zero voltage drop digital optoelectronic metering installation |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106168658A (en) * | 2016-08-31 | 2016-11-30 | 宋天斌 | A kind of device and method reducing voltage transformer secondary voltage drop |
| CN112213685A (en) * | 2020-06-02 | 2021-01-12 | 青岛鼎信通讯股份有限公司 | CT compensation method for electric energy meter |
| CN114252674A (en) * | 2021-12-15 | 2022-03-29 | 中国化学工程第十一建设有限公司 | Secondary wiring detection device and method |
-
2007
- 2007-10-11 CN CNA2007100535251A patent/CN101173966A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106168658A (en) * | 2016-08-31 | 2016-11-30 | 宋天斌 | A kind of device and method reducing voltage transformer secondary voltage drop |
| CN106168658B (en) * | 2016-08-31 | 2023-06-02 | 贵州电网有限责任公司 | Device and method for reducing secondary voltage drop of voltage transformer |
| CN112213685A (en) * | 2020-06-02 | 2021-01-12 | 青岛鼎信通讯股份有限公司 | CT compensation method for electric energy meter |
| CN114252674A (en) * | 2021-12-15 | 2022-03-29 | 中国化学工程第十一建设有限公司 | Secondary wiring detection device and method |
| CN114252674B (en) * | 2021-12-15 | 2023-09-22 | 中国化学工程第十一建设有限公司 | Secondary wiring detection device and method |
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