A novel high voltage detector that can be integrated into SPIC (Smart Power IC) is proposed.The structure is designed on the basis of normal junction terminal technique of FFLR (Floating Field Limiting Rings) system....A novel high voltage detector that can be integrated into SPIC (Smart Power IC) is proposed.The structure is designed on the basis of normal junction terminal technique of FFLR (Floating Field Limiting Rings) system.The field limiting ring as a voltage divider,is used to optimize the surface field.The voltage of main junction increases from 0 to a high value,while the utmost ring is designed to vary within a small range,which can be handled by using low voltage logic circuits.An example of 400V rings system is analyzed and simulated for this structure.The results prove that the high voltage detector can detect high voltage in SPIC.The structure can be integrated into SPIC.Besides,it is compatible with CMOS or BCD(Bipolar CMOS Dmos) technology,without any additional processes required.展开更多
A high performance current and voltage measurement system has been developed in power system. The system is composed of two parts: one current measurement element and one voltage measurement element. A Rogowski coil ...A high performance current and voltage measurement system has been developed in power system. The system is composed of two parts: one current measurement element and one voltage measurement element. A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements. Active electronic components are used to modulate signal, and power supply for these components is drawn from power line via an auxiliary current transformer. Measurement signal is transmitted by optical fibers, which is resistant to electromagnetic induction and noise. With careful design and the use of digital signal processing technology, the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use.展开更多
Self-heating and electric field distribution are the primary factors affecting the accuracy of the Ultra High Voltage Direct Current(UHVDC)resistive divider.Reducing the internal temperature rise of the voltage divide...Self-heating and electric field distribution are the primary factors affecting the accuracy of the Ultra High Voltage Direct Current(UHVDC)resistive divider.Reducing the internal temperature rise of the voltage divider caused by self-heating,reducing the maximum electric field strength of the voltage divider,and uniform electric field distribution can effectively improve the UHVDC resistive divider’s accuracy.In this paper,thermal analysis and electric field distribution optimization design of 1200 kV UHVDC resistive divider are carried out:(1)Using the proposed iterative algorithm,the heat dissipation and temperature distribution of the high voltage DC resistive divider are studied,and the influence of the ambient temperature and the power of the divider on the temperature of the insulating medium of the divider is analyzed;(2)Established the finite element models of 1200 kV and 2×600 kV DC resistive dividers,analyzed the influence of the size of the grading ring and the installation position on the maximum electric field strength of the voltage divider,and calculated the impact of the shielding resistor layer on the vicinity of the measuring resistor layer.The research indicates that:(1)The temperature of the insulating medium is linearly related to the horsepower of the voltage divider and the ambient temperature;(2)After the optimized design of the electric field,the maximum electric field strength of the 1200 kV DC resistive divider is reduced to 1471 V/mm,which is about 24% lower than that of the unoptimized design;(3)Installing the shielding resistor layer can significantly improve the electric field near the measuring resistor layer.This paper has an important reference function for improving the accuracy of the UHVDC resistive divider.展开更多
To address the lack of voltage ratio standards for accuracy testing of low-frequency voltage transformers,it is necessary to develop a 3 kV low-frequency induction voltage divider.Firstly,based on the analysis of the ...To address the lack of voltage ratio standards for accuracy testing of low-frequency voltage transformers,it is necessary to develop a 3 kV low-frequency induction voltage divider.Firstly,based on the analysis of the error sources of the induction voltage divider,a method was proposed to calculate the excitation impedance of the induction voltage divider using complex magnetic permeability.A measurement circuit based on the lock-in principle was set up to measure the complex magnetic permeability of grained-oriented silicon steel 30P100 and permalloy 1J85 at different frequencies.Secondly,a 3 kV low-frequency induction voltage divider with a two-stage excitation and a series-wound ra-tio winding in 10 sections was designed.The errors of the two stages of the instrument transformers were calculated at 20 and 50 Hz,respectively.Finally,the divider's errors were calibrated at 20 and 50 Hz using the reference potential method.The results showed that,compared to 50 Hz,the excitation impedance of the two stages decreased and the errors increased at 20 Hz,with the overall error of the induction voltage divider being better at 50 Hz than at 20 Hz.Experimental measurements indicated that at 20 Hz,the ratio error and phase error of the 3 kV two-stage excitation induction voltage divider were better than 110-5,whereas at 50 Hz,the errors were better than 110-6.This study provides support for the accuracy testing of voltage transformers used in low-frequency flexible AC transmission projects.展开更多
Voltage measuring equipment in power grids often requires capacitive voltage dividers to realize conversion of high voltage electrical quantities to low voltage signal quantities.The new floating-ground capacitive vol...Voltage measuring equipment in power grids often requires capacitive voltage dividers to realize conversion of high voltage electrical quantities to low voltage signal quantities.The new floating-ground capacitive voltage divider(FG-CVD)can eliminate original lumped capacitors and its supporting insulation structures by adopting precisely designed parasitic capacitance as a high voltage arm capacitor,which can greatly save cost and volume.However,the utilization of parasitic capacitance not only makes FG-CVD sensitive to external conductor interference,but also causes transient waveform distortion,especially when the connecting lead between the FG-CVD and high-voltage conductor is lengthy.On the basis of transfer characteristic analysis,this paper proposes a complete parameter design method for FG-CVD to improve stability of its transfer ratio under interference of the external conductor.Moreover,by establishing a wideband equivalent model with lead inductance,the transient waveform distortion problem of FG-CVD is well explained,and a resistance compensation scheme is also proposed to reduce ratio error.Finally,a 500:1 FG-CVD prototype with a measurement bandwidth of 2MHz is developed.Experimental results show the prototype has high accuracy in both power frequency and lightning pulse voltage measurement,and ratio error decreases from 20.33%to less than 1.3%.展开更多
With the increase of the operating voltage and enlargement of the size of the capacitor voltage transformer(CVT),the additional measurement error caused by stray capacitance coupling and leakage current along the poll...With the increase of the operating voltage and enlargement of the size of the capacitor voltage transformer(CVT),the additional measurement error caused by stray capacitance coupling and leakage current along the polluted surface of the CVT becomes noticeable.The equipotential shielding CVT(EPSCVT)was proposed and designed by the authors to mitigate these effects.An improved conceptual design option of the EPS-CVT is presented in this paper with special references to this study to improve the shielding effect without the increase of shielding capacitance.A proposed method of non-uniform capacitance configuration can improve the shielding effect significantly without an increase of the external shielding capacitance.Based on this achievement,the potential difference and the capacitive current exchange between the internal measuring system and external shielding systems are significantly reduced.In the evaluation of the shielding effect for the influence of stray capacitance,compared with a conventional CVT with equal capacitance,EPS-CVT can reduce the measurement error by two orders of magnitude.In addition,the measurement error caused by the leakage current can also be greatly reduced,especially for the reduction of the phase angle error.Based on the improved design method,a design scheme for an engineering application is proposed which can achieve effective shielding while ensuring as good a technical performance as the existing CVT.展开更多
文摘A novel high voltage detector that can be integrated into SPIC (Smart Power IC) is proposed.The structure is designed on the basis of normal junction terminal technique of FFLR (Floating Field Limiting Rings) system.The field limiting ring as a voltage divider,is used to optimize the surface field.The voltage of main junction increases from 0 to a high value,while the utmost ring is designed to vary within a small range,which can be handled by using low voltage logic circuits.An example of 400V rings system is analyzed and simulated for this structure.The results prove that the high voltage detector can detect high voltage in SPIC.The structure can be integrated into SPIC.Besides,it is compatible with CMOS or BCD(Bipolar CMOS Dmos) technology,without any additional processes required.
文摘A high performance current and voltage measurement system has been developed in power system. The system is composed of two parts: one current measurement element and one voltage measurement element. A Rogowski coil and a capacitive voltage divider are used respectively for the line current and voltage measurements. Active electronic components are used to modulate signal, and power supply for these components is drawn from power line via an auxiliary current transformer. Measurement signal is transmitted by optical fibers, which is resistant to electromagnetic induction and noise. With careful design and the use of digital signal processing technology, the whole system can meet 0.5% accuracy for metering and provides large dynamic range coupled with good accuracy for protective relaying use.
基金supported by the Science and Technology Project of China Electric Power Research Institute,Research on 1200 kV DC Voltage Proportional Metering Technology with Weak Environmental Sensitivity and Development of Standard Devices(JL83-21-002).
文摘Self-heating and electric field distribution are the primary factors affecting the accuracy of the Ultra High Voltage Direct Current(UHVDC)resistive divider.Reducing the internal temperature rise of the voltage divider caused by self-heating,reducing the maximum electric field strength of the voltage divider,and uniform electric field distribution can effectively improve the UHVDC resistive divider’s accuracy.In this paper,thermal analysis and electric field distribution optimization design of 1200 kV UHVDC resistive divider are carried out:(1)Using the proposed iterative algorithm,the heat dissipation and temperature distribution of the high voltage DC resistive divider are studied,and the influence of the ambient temperature and the power of the divider on the temperature of the insulating medium of the divider is analyzed;(2)Established the finite element models of 1200 kV and 2×600 kV DC resistive dividers,analyzed the influence of the size of the grading ring and the installation position on the maximum electric field strength of the voltage divider,and calculated the impact of the shielding resistor layer on the vicinity of the measuring resistor layer.The research indicates that:(1)The temperature of the insulating medium is linearly related to the horsepower of the voltage divider and the ambient temperature;(2)After the optimized design of the electric field,the maximum electric field strength of the 1200 kV DC resistive divider is reduced to 1471 V/mm,which is about 24% lower than that of the unoptimized design;(3)Installing the shielding resistor layer can significantly improve the electric field near the measuring resistor layer.This paper has an important reference function for improving the accuracy of the UHVDC resistive divider.
基金The Innovation Fund Project of China Electric Power Research Institute:Research on accuracy test method of voltage transformer for low-frequency transmission and development of test system,Grant/Award Number:GY83-22-005。
文摘To address the lack of voltage ratio standards for accuracy testing of low-frequency voltage transformers,it is necessary to develop a 3 kV low-frequency induction voltage divider.Firstly,based on the analysis of the error sources of the induction voltage divider,a method was proposed to calculate the excitation impedance of the induction voltage divider using complex magnetic permeability.A measurement circuit based on the lock-in principle was set up to measure the complex magnetic permeability of grained-oriented silicon steel 30P100 and permalloy 1J85 at different frequencies.Secondly,a 3 kV low-frequency induction voltage divider with a two-stage excitation and a series-wound ra-tio winding in 10 sections was designed.The errors of the two stages of the instrument transformers were calculated at 20 and 50 Hz,respectively.Finally,the divider's errors were calibrated at 20 and 50 Hz using the reference potential method.The results showed that,compared to 50 Hz,the excitation impedance of the two stages decreased and the errors increased at 20 Hz,with the overall error of the induction voltage divider being better at 50 Hz than at 20 Hz.Experimental measurements indicated that at 20 Hz,the ratio error and phase error of the 3 kV two-stage excitation induction voltage divider were better than 110-5,whereas at 50 Hz,the errors were better than 110-6.This study provides support for the accuracy testing of voltage transformers used in low-frequency flexible AC transmission projects.
基金supported by the Science and Technology Project of SGCC under Contract 5500-202140126A-0-0-00.
文摘Voltage measuring equipment in power grids often requires capacitive voltage dividers to realize conversion of high voltage electrical quantities to low voltage signal quantities.The new floating-ground capacitive voltage divider(FG-CVD)can eliminate original lumped capacitors and its supporting insulation structures by adopting precisely designed parasitic capacitance as a high voltage arm capacitor,which can greatly save cost and volume.However,the utilization of parasitic capacitance not only makes FG-CVD sensitive to external conductor interference,but also causes transient waveform distortion,especially when the connecting lead between the FG-CVD and high-voltage conductor is lengthy.On the basis of transfer characteristic analysis,this paper proposes a complete parameter design method for FG-CVD to improve stability of its transfer ratio under interference of the external conductor.Moreover,by establishing a wideband equivalent model with lead inductance,the transient waveform distortion problem of FG-CVD is well explained,and a resistance compensation scheme is also proposed to reduce ratio error.Finally,a 500:1 FG-CVD prototype with a measurement bandwidth of 2MHz is developed.Experimental results show the prototype has high accuracy in both power frequency and lightning pulse voltage measurement,and ratio error decreases from 20.33%to less than 1.3%.
文摘With the increase of the operating voltage and enlargement of the size of the capacitor voltage transformer(CVT),the additional measurement error caused by stray capacitance coupling and leakage current along the polluted surface of the CVT becomes noticeable.The equipotential shielding CVT(EPSCVT)was proposed and designed by the authors to mitigate these effects.An improved conceptual design option of the EPS-CVT is presented in this paper with special references to this study to improve the shielding effect without the increase of shielding capacitance.A proposed method of non-uniform capacitance configuration can improve the shielding effect significantly without an increase of the external shielding capacitance.Based on this achievement,the potential difference and the capacitive current exchange between the internal measuring system and external shielding systems are significantly reduced.In the evaluation of the shielding effect for the influence of stray capacitance,compared with a conventional CVT with equal capacitance,EPS-CVT can reduce the measurement error by two orders of magnitude.In addition,the measurement error caused by the leakage current can also be greatly reduced,especially for the reduction of the phase angle error.Based on the improved design method,a design scheme for an engineering application is proposed which can achieve effective shielding while ensuring as good a technical performance as the existing CVT.
