High-accuracy electronic voltage transformer for broadband voltage measurement

Abstract

The invention discloses a high-accuracy electronic voltage transformer for broadband voltage measurement, which comprises a capacitive voltage divider, an optical sensor, a power frequency reference voltage acquisition module and a signal processing part, and is characterized in that the capacitive voltage divider comprises a high-voltage capacitive voltage divider, a first low-voltage capacitive voltage divider, a second low-voltage capacitive voltage divider, a signal output terminal and a grounding terminal; the electrodes of the optical sensor are connected in parallel to the two ends of the first low-voltage capacitive voltage divider, and the power frequency reference voltage acquisition module is connected in parallel to the two ends of the second low-voltage capacitive voltage divider and comprises an electromagnetic unit, a power frequency voltage acquisition card and a power supply unit. And the optical sensor and the power frequency reference voltage acquisition module are connected with the signal processing part. By adopting the high-accuracy electronic voltage transformer for broadband voltage measurement, the problem of measurement precision temperature drift caused by temperature influence of an existing capacitive voltage division type optical voltage transformer is solved.

Description

Technical Field

[0001] The invention relates to the technical field of voltage transformers, and in particular to a high-accuracy electronic voltage transformer for wide-band voltage measurement. Background Art

[0002] Driven by energy transformation and technological progress, a high proportion of renewable energy and power electronic equipment are becoming important trends and key features in the development of power systems. Power signals have the characteristics of wide bandwidth, fast changes, and high noise. The inherent nonlinear characteristics of power electronic equipment inject a large number of broadband signals such as interharmonics and higher harmonics into the power grid, making the power system signals more complex, and serious broadband oscillation has occurred, threatening the safe and stable operation of the power grid.

[0003] Making signals "observable" and "measurable" is the basis for analyzing, protecting, and stabilizing the control of the system. Under the new power system environment, the observability and measurability of the power system also needs to be improved accordingly, and broadband measurement devices will play an increasingly important role. Among them, the voltage transformer is an indispensable and important measurement equipment in the power system. Its measurement accuracy and operation stability are directly related to the safe, stable and economical operation of the power system. The optical voltage transformer based on the Pockels electro-optical effect has important applications in smart grids, high-voltage power systems and other fields with extremely high measurement requirements due to its unique technical advantages such as high precision, wide measurement bandwidth and no saturation. It represents the frontier direction of the development of electronic voltage transformer technology.

[0004] Optical voltage transformers can be divided into full-voltage optical voltage transformers, laminated dielectric voltage-dividing optical voltage transformers, capacitor voltage-dividing optical voltage transformers, and distributed optical voltage transformers. Among them, the capacitor voltage-dividing optical voltage transformer combines the stability of capacitor voltage-dividing technology and the high precision of optical sensing technology, making it an ideal choice for voltage measurement in power systems. The capacitor voltage-dividing voltage transformer uses the principle of capacitor voltage-dividing to reduce high voltage to a certain proportion of low voltage, and then transmits this low voltage to the optical sensor. The voltage signal is applied to the electro-optical crystal to form transverse electro-optical modulation or longitudinal electro-optical modulation, which causes the polarized light passing through the crystal to produce birefringence. The Pockels effect causes the two beams of birefringence to produce a phase difference. As long as the phase difference is measured, the magnitude of the external voltage to be measured can be accurately measured.

[0005] Capacitor voltage divider type optical voltage transformer has the advantages of no magnetic saturation, no frequency band measurement limitation, and can accurately reflect the full voltage information including non-periodic components. However, capacitor voltage divider type optical voltage transformer has the problem of temperature drift of measurement accuracy caused by temperature. The problem of temperature drift of measurement accuracy is caused by the working characteristics of the electro-optical crystal, the core component of the optical voltage sensor (OVS), which is affected by temperature. Until now, the problem of temperature drift of measurement accuracy is still the main problem to be solved by optical voltage transformer. Summary of the invention

[0006] The purpose of the present invention is to provide a high-accuracy electronic voltage transformer for broadband voltage measurement, solve the problem of temperature drift of measurement accuracy caused by temperature influence of existing capacitive voltage divider type optical voltage transformer, and propose a new compensation method for the temperature drift of measurement accuracy.

[0007] The present invention provides a high-accuracy electronic voltage transformer for wideband voltage measurement, comprising a capacitor voltage divider, an optical sensor, an industrial frequency reference voltage acquisition module and a signal processing part, wherein the capacitor voltage divider comprises a high-voltage capacitor voltage divider, a first low-voltage capacitor voltage divider, a second low-voltage capacitor voltage divider, a signal output terminal and a grounding terminal, electrodes of the optical sensor are connected in parallel at both ends of the first low-voltage capacitor voltage divider, the industrial frequency reference voltage acquisition module is connected in parallel at both ends of the second low-voltage capacitor voltage divider, the industrial frequency reference voltage acquisition module comprises an electromagnetic unit, an industrial frequency voltage acquisition card and a power supply unit, the optical sensor and the industrial frequency reference voltage acquisition module are connected to the signal processing part, and the signal processing part comprises an optical signal processing unit, a temperature compensation correction unit, an acquisition unit and a monitoring and analysis host.

[0008] Preferably, the high-voltage capacitive voltage divider, the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider are sequentially connected in series from top to bottom.

[0009] Preferably, the high voltage terminal of the high voltage capacitor voltage divider is connected to the voltage to be measured U1, and a low voltage U2 proportional to the voltage to be measured U1 is formed at both ends of the first low voltage capacitor voltage divider through the voltage dividing action of the first low voltage capacitor voltage divider and the second low voltage capacitor voltage divider, and a low voltage U3 proportional to the voltage to be measured U1 is formed at both ends of the second low voltage capacitor voltage divider, and the voltage relationship is as follows:

[0010]

[0011] Wherein C1, C2 and C3 are the capacitance values ​​of the high-voltage capacitive voltage divider, the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider respectively; k1 and k2 are the voltage division ratios of the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider respectively.

[0012] Preferably, the optical sensor, under the triggering of the SLD light source in the optical signal processing unit, inputs the optical signal modulated by the first low-voltage capacitor into the photoelectric signal processing unit, and the optical signal processing unit converts the received optical signal into 光(f＝50Hz) and U 光(f＝all) Two voltage signals are input to the temperature compensation correction unit;

[0013] U 光(f＝50Hz) =k0(t)U 2(f＝50Hz)

[0014] U 光(f＝all) =k0(t)U 2(f＝all)

[0015] Among them, U 光(f＝50Hz) is the power frequency voltage output of the optical voltage transformer; U 光(f＝all) is the broadband voltage output of the optical voltage transformer; k0(t) is the transmission coefficient of the optical voltage transformer at this temperature.

[0016] Preferably, the electromagnetic unit transmits the voltage of the second low-voltage capacitor to the power frequency voltage acquisition card and outputs U 基准(f＝50Hz) ;

[0017] in,

[0018] U 基准(f＝50Hz) =k3U 3(f＝50Hz)

[0019] Where U 基准(f＝50Hz) is the industrial frequency reference voltage output; k3 is the electromagnetic unit transmission coefficient.

[0020] Preferably, the optical voltage transformer power frequency voltage output U 光(f＝50Hz) With the industrial frequency reference voltage output U 基准(f＝50Hz) The optical sensors are input into the temperature compensation calculation module, and the optical sensor real-time correction coefficient Δk(t) is obtained through mathematical processing.

[0021]

[0022] Where Δk(t) is the real-time compensation value of the optical sensing coefficient; is the compensation calculation function; U 基准(f＝50Hz) Compensate for the baseline value.

[0023] Preferably, the optical voltage transformer has a broadband voltage output U 光(f＝all) The optical sensor corrects the transmission coefficient Δk(t) in real time and obtains the calibration value U through the optical broadband voltage calibration module * 光(f＝all) Output to the acquisition unit;

[0024] k1(t)=k0(t)+Δk(t)

[0025] U * 光(f＝all) =k1(t)k1U 1(f＝all)

[0026] k1(t) is the optical sensor transmission coefficient at this temperature after compensation, U * 光(f＝all) It is a calibrated optical voltage transformer with wide-band output; the industrial frequency reference voltage acquisition module also includes a power supply unit, which takes energy from the secondary side of the electromagnetic unit and converts it into a power supply for the signal processing part.

[0027] Therefore, the present invention adopts the above-mentioned high-accuracy electronic voltage transformer for wide-band voltage measurement to solve the problem of temperature drift of measurement accuracy caused by temperature influence in the existing capacitor voltage-dividing optical voltage transformer.

[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a system structure diagram of a high-accuracy electronic voltage transformer for wide-band voltage measurement according to the present invention;

[0030] Figure 2 This is a structural diagram of a temperature compensation correction unit of a high-accuracy electronic voltage transformer for wide-band voltage measurement according to the present invention;

[0031] Figure 3 This is a diagram showing the internal structure of an industrial frequency reference voltage acquisition module of a high-accuracy electronic voltage transformer for wide-band voltage measurement according to the present invention.

[0032] Reference numerals

[0033] 1. Capacitor voltage divider; 11. High-voltage capacitor voltage divider; 12. First low-voltage capacitor voltage divider; 13. Second low-voltage capacitor voltage divider; 2. Optical sensor; 3. Power frequency reference voltage acquisition module; 31. Electromagnetic unit; 32. Power frequency voltage acquisition card; 33. Power supply unit; 4. Signal processing part; 41. Optical signal processing unit; 42. Temperature compensation correction unit; 43. Acquisition unit; 44. Monitoring and analysis host. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0036] Embodiment 1

[0037] like Figure 1-Figure 3 As shown, the present invention provides a high-accuracy electronic voltage transformer for wide-band voltage measurement, comprising a capacitive voltage divider, an optical sensor, an industrial frequency reference voltage acquisition module and a signal processing part, wherein the capacitive voltage divider comprises a high-voltage capacitive voltage divider, a first low-voltage capacitive voltage divider, a second low-voltage capacitive voltage divider, a signal output terminal and a grounding terminal, and the high-voltage capacitive voltage divider, the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider are sequentially connected in series from top to bottom.

[0038] The electrodes of the optical sensor are connected in parallel at both ends of the first low-voltage capacitor voltage divider, the industrial frequency reference voltage acquisition module is connected in parallel at both ends of the second low-voltage capacitor voltage divider, the industrial frequency reference voltage acquisition module includes an electromagnetic unit, an industrial frequency voltage acquisition card and a power supply unit, the optical sensor and the industrial frequency reference voltage acquisition module are connected to a signal processing part, and the signal processing part includes an optical signal processing unit, a temperature compensation correction unit, an acquisition unit and a monitoring and analysis host.

[0039] The signal processing part 4 includes an optical signal processing unit 41, a temperature compensation correction unit 42, an acquisition unit 43 and a monitoring and analysis host 44. The optical signal processing unit 41 receives the optical signal from the optical sensor 2 and outputs two signals of power frequency voltage measurement and broadband voltage measurement to the temperature compensation correction unit 42. In addition to receiving the above two signals, the temperature compensation correction unit 42 also receives the power frequency voltage reference value signal from the power frequency reference voltage acquisition module 3, and provides one output to the acquisition unit 43 to be sent to the monitoring and analysis host 44.

[0040] The temperature compensation correction unit 42 is composed of an optical sensor temperature compensation calculation module and an optical broadband voltage calibration module. The optical power frequency voltage measurement output U 光(f＝50Hz) The power frequency voltage reference value output U of the power frequency reference voltage acquisition module 3 基准(f＝50Hz) The optical sensor temperature compensation calculation module is used to obtain the optical sensor real-time correction coefficient k1(t)=k0(t)+Δk(t) and the optical broadband voltage measurement output U of the optical sensor. 光(f＝all) The optical voltage transformer is input to the optical broadband voltage calibration module and outputs the calibrated optical voltage transformer broadband output U * 光(f＝all) To the collection unit 43, and finally to the monitoring and analysis host 44.

[0041] The power frequency reference voltage acquisition module 3 further includes a power supply unit 33 , which obtains energy from the secondary side of the electromagnetic unit 31 and converts it into a power supply for supplying power to the signal processing part 4 .

[0042] The high voltage terminal of the high voltage capacitor voltage divider is connected to the voltage to be measured U1. Through the voltage dividing action of the first low voltage capacitor voltage divider and the second low voltage capacitor voltage divider, a low voltage U2 proportional to the voltage to be measured U1 is formed at both ends of the first low voltage capacitor voltage divider, and a low voltage U3 proportional to the voltage to be measured U1 is formed at both ends of the second low voltage capacitor voltage divider. The voltage relationship is as follows:

[0043]

[0044] Wherein C1, C2 and C3 are the capacitance values ​​of the high voltage capacitive voltage divider, the first low voltage capacitive voltage divider and the second low voltage capacitive voltage divider respectively, and k1 and k2 are the voltage division ratios of the first low voltage capacitive voltage divider and the second low voltage capacitive voltage divider respectively.

[0045] The optical sensor, under the triggering of the SLD light source in the optical signal processing unit, transmits the optical signal modulated by the first low-voltage capacitor to the photoelectric signal processing unit, and the optical signal processing unit converts the received optical signal into U 光(f＝50Hz) and U 光(f＝all) Two voltage signals are input to the temperature compensation correction unit.

[0046] U 光(f＝50Hz) =k0(t)U 2(f＝50Hz)

[0047] U 光(f＝all) =k0(t)U 2(f＝all)

[0048] Among them, U 光(f＝50Hz) is the power frequency voltage output of the optical voltage transformer; U 光(f＝all) is the broadband voltage output of the optical voltage transformer; k0(t) is the transmission coefficient of the optical voltage transformer at this temperature.

[0049] The electromagnetic unit transmits the voltage of the second low-voltage capacitor to the power frequency voltage acquisition card and outputs U 基准(f＝50Hz) ,

[0050] in,

[0051] U 基准(f＝50Hz) =k3U 3(f＝50Hz)

[0052] Where U 基准(f＝50Hz) is the industrial frequency reference voltage output, and k3 is the electromagnetic unit transmission coefficient.

[0053] Optical voltage transformer power frequency voltage output U 光(f＝50Hz) With the industrial frequency reference voltage output U 基准(f＝50Hz) The data are input into the optical sensor temperature compensation calculation module, and the optical sensor real-time correction transmission coefficient Δk(t) is obtained through mathematical processing.

[0054]

[0055] Where Δk(t) is the real-time compensation value of the optical sensing coefficient; is the compensation calculation function; U 基准(f＝50Hz) Compensate for the baseline value.

[0056] Optical voltage transformer broadband voltage output U 光(f＝all) The optical sensor real-time corrects the transmission coefficient Δk(t) and obtains the calibration value U through the optical broadband voltage calibration module * 光(f＝all) Output to the acquisition unit,

[0057] k1(t)=k0(t)+Δk(t)

[0058] U * 光(f＝all) =k1(t)k1U 1(f＝all)

[0059] k1(t) is the optical sensor transmission coefficient at this temperature after compensation, U * 光(f＝all) It is a calibrated optical voltage transformer with wide-band output;

[0060] The industrial frequency reference voltage acquisition module also includes a power supply unit, which takes energy from the secondary side of the electromagnetic unit and converts it into a power supply for the signal processing part.

[0061] Therefore, the present invention adopts the above-mentioned high-accuracy electronic voltage transformer for wide-band voltage measurement to solve the problem of temperature drift of measurement accuracy caused by temperature influence in the existing capacitor voltage-dividing optical voltage transformer.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A high-accuracy electronic voltage transformer for broadband voltage measurement, characterized in that: It includes a capacitive voltage divider, an optical sensor, an industrial frequency reference voltage acquisition module and a signal processing part. The capacitive voltage divider includes a high-voltage capacitive voltage divider, a first low-voltage capacitive voltage divider, a second low-voltage capacitive voltage divider, a signal output terminal and a ground terminal. The electrodes of the optical sensor are connected in parallel at both ends of the first low-voltage capacitive voltage divider. The industrial frequency reference voltage acquisition module is connected in parallel at both ends of the second low-voltage capacitive voltage divider. The industrial frequency reference voltage acquisition module includes an electromagnetic unit, an industrial frequency voltage acquisition card and a power supply unit. The optical sensor and the industrial frequency reference voltage acquisition module are connected to the signal processing part. The signal processing part includes an optical signal processing unit, a temperature compensation correction unit, a collection unit and a monitoring and analysis host.

2. A high-accuracy electronic voltage transformer for wide-band voltage measurement according to claim 1, characterized in that: The high-voltage capacitive voltage divider, the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider are sequentially connected in series from top to bottom.

3. The high-accuracy electronic voltage transformer for broadband voltage measurement according to claim 1, characterized in that: The high voltage terminal of the high voltage capacitor voltage divider is connected to the voltage to be measured U1. Through the voltage dividing action of the first low voltage capacitor voltage divider and the second low voltage capacitor voltage divider, a low voltage U2 proportional to the voltage to be measured U1 is formed at both ends of the first low voltage capacitor voltage divider, and a low voltage U3 proportional to the voltage to be measured U1 is formed at both ends of the second low voltage capacitor voltage divider. The voltage relationship is as follows: Wherein C1, C2 and C3 are the capacitance values ​​of the high-voltage capacitive voltage divider, the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider respectively; k1 and k2 are the voltage division ratios of the first low-voltage capacitive voltage divider and the second low-voltage capacitive voltage divider respectively.

4. The high-accuracy electronic voltage transformer for broadband voltage measurement according to claim 1, characterized in that: The optical sensor, under the triggering of the SLD light source in the optical signal processing unit, transmits the optical signal modulated by the first low-voltage capacitor to the photoelectric signal processing unit, and the optical signal processing unit converts the received optical signal into U 光(f＝50Hz) and U 光(f＝all) Two voltage signals are input to the temperature compensation correction unit; U 光(f＝50Hz) =k0(t)U 2(f＝50Hz) U 光(f＝all) =k0(t)U 2(f＝all) Among them, U 光(f＝50Hz) is the power frequency voltage output of the optical voltage transformer; U 光(f＝all) is the broadband voltage output of the optical voltage transformer; k0(t) is the transmission coefficient of the optical voltage transformer at this temperature.

5. The high-accuracy electronic voltage transformer for wide-band voltage measurement according to claim 1, characterized in that: The electromagnetic unit transmits the voltage of the second low-voltage capacitor to the power frequency voltage acquisition card and outputs U 基准(f＝50Hz) ; in, U 基准(f＝50Hz) =k3U 3(f＝50Hz) Where U 基准(f＝50Hz) is the industrial frequency reference voltage output; k3 is the electromagnetic unit transmission coefficient.

6. A high-accuracy electronic voltage transformer for wide-band voltage measurement according to claim 1, characterized in that: Optical voltage transformer power frequency voltage output U 光(f＝50Hz) With the industrial frequency reference voltage output U 基准(f＝50Hz) The optical sensors are input into the temperature compensation calculation module, and the optical sensor real-time correction coefficient Δk(t) is obtained through mathematical processing. Where Δk(t) is the real-time compensation value of the optical sensing coefficient; is the compensation calculation function; U 基准(f＝50Hz) Compensate for the baseline value.

7. A high-accuracy electronic voltage transformer for wide-band voltage measurement according to claim 1, characterized in that: Optical voltage transformer broadband voltage output U 光(f＝all) The optical sensor real-time corrects the transmission coefficient Δk(t) and obtains the calibration value U through the optical broadband voltage calibration module * 光(f＝all) Output to the acquisition unit; k1(t)=k0(t)+Δk(t) U * 光(f＝all) =k1(t)k1U 1(f＝all) k1(t) is the optical sensor transmission coefficient at this temperature after compensation, U * 光(f＝all) It is a calibrated optical voltage transformer with wide-band output; the industrial frequency reference voltage acquisition module also includes a power supply unit, which takes energy from the secondary side of the electromagnetic unit and converts it into a power supply for the signal processing part.

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