Non-contact Voltage Measurement Research Articles

A Knowledge-Based Cooperative Co-Evolutionary Algorithm for Non-Contact Voltage Measurement

A Knowledge-Based Cooperative Co-Evolutionary Algorithm for Non-Contact Voltage Measurement

Research on Noncontact Voltage Measurement Method for Three-Phase Busbar of Low-Voltage Distribution Cabinets

Research on Noncontact Voltage Measurement Method for Three-Phase Busbar of Low-Voltage Distribution Cabinets

Non-contact voltage measurement of residential cables based on internal parameter conversion and centering probe assistance

Existing non-contact voltage measurement technology cannot be applied to residential cables containing neutral wire and earth wire in addition to live wire. A non-contact voltage measurement method of residential cables is introduced in this article. First, an equivalent circuit model of the residential cable measurement based on capacitive coupling is established. In order to solve the problem of uncertain coupling capacitance, which leading to the inability to accurately obtain the voltage amplitude, a calibration method based on internal parameter conversion and centering probe assistance is proposed. This method calibrates the cable voltage through different transfer relationships and sensor outputs, and no known reference excitation is required during calibration. Subsequently, the impact of internal parameters on measurement accuracy are analyzed and selection principles are provided. Through finite element simulation, the influence of metal spring for centering on voltage measurement is analyzed, and the measurement error of non-ideal cables (with eccentricity or ovality) is quantified. A prototype probe and internal parameter conversion circuit have been developed, and parasitic capacitance compensation have been completed. The measurement accuracy of 50 Hz voltage in a certain range (100–300 V) was tested in the laboratory, the maximum relative error of amplitude is −0.89%, and the relative error of phase is 0.68%. Four specifications of residential cables testing were completed, with a maximum relative error of −1.35%. Long- term testing was conducted on the actual field (output voltage of the distribution box), the test results showed that the output was linear, and the relative error were kept around 0.65% after primary calibration.

Non-Contact Adaptive Voltage Sensor Based on Electric Field Coupling Principle.

Non-contact voltage sensors based on the principle of electric field coupling have the advantages of simple loading and unloading, high construction safety, and the fact that they are not affected by line insulation. They can accurately measure line voltage without the need to connect to the measured object. Starting from the principle of non-contact voltage measurement, this article abstracts a non-contact voltage measurement model into the principle of capacitive voltage sharing and deduces its transfer relationship. Secondly, it is theoretically inferred that the edge effect of the traditional symmetric structure sensor plate will cause the actual capacitance value between the sensor plates to be greater than the theoretically calculated capacitance value, resulting in a certain measurement error. Therefore, the addition of an equipotential ring structure is proposed to eliminate the edge additional capacitance caused by the edge effect in order to design the sensor structure. In addition, due to the influence of sensor volume, material dielectric constant, and other factors, the capacitance value of the sensor itself is only at pF level, resulting in poor low-frequency performance and imbuing the sensor with a low voltage division ratio. In this regard, this article analyzes the measurement principle of non-contact voltage sensors. By paralleling ceramic capacitors between the two electrode plates of the sensor, the capacitance of the sensor itself is effectively increased, improving the low-frequency performance of the sensor while also increasing the sensor's voltage division ratio. In addition, by introducing a single pole double throw switch to switch parallel capacitors with different capacitance values, the sensor can have different voltage division ratios in different measurement scenarios, giving it a certain degree of adaptability. The final sensor prototype was made, and a high and low voltage experimental platform was built to test the sensor performance. The experimental results showed that the sensor has good linearity and high measurement accuracy, with a ratio error of within ±3%.

Research on Non-Contact Voltage Measurement Method Based on Near-End Electric Field Inversion

Aiming at the problems of complex equations, low accuracy, and the strict measurement point layout requirements of the existing electric field integration method, a non-contact measurement method based on the inversion voltage of the near electric field is proposed. Firstly, the field source relationship is clarified, the connection between the spatial electric field and the voltage is derived, and a near-end electric field inversion method is proposed. Secondly, a three-dimensional simulation model of an overhead line is established using COMSOL finite element software, the three-dimensional spatial potential distribution of the overhead line is obtained, and the voltage is inverted and calculated. Finally, an overhead line simulation test platform was built, and MEMS electric field sensors were used for testing and verification. The results show that the maximum error of the three-phase voltage inversion of the proximal electric field measurement is 6.8%, and the error between the voltage obtained by the experimental inversion measurement and the reference voltage is less than 7.2%. The simulation and experimental results also verify the accuracy and feasibility of the inversion voltage of the proximal electric field. The results of this paper can lay a foundation for the practical application of small and miniaturized electric field sensors, and help in the construction and development of smart grids.

Simulation and Optimization of Embedded Voltage Sensor in High Voltage Insulator

In the smart grid, the voltage measurement of the power system is of great significance to the measurement of electric energy, the correct operation of the relay protection device, and the measurement of the voltage of the transmission line. The main methods of high voltage (35-220kV) measurement are contact and non-contact. Contact measurement has many defects, and non-contact voltage measurement has become a research hotspot. While capacitive voltage sensors are the main non-contact measurement method, currently known capacitive voltage sensors have some disadvantages, such as separation of the resin from the elements constituting the capacitive sensor due to resin bubbles of the dielectric material arranged around the sensor assembly, Unnecessary partial discharge occurs because the resin does not fully adhere and/or clamp the sensor device completely. In view of the above problems, this paper proposes a built-in integrated voltage sensor, which is placed inside the insulator. The multi-layer and through-hole holes perfectly avoid the occurrence of bubbles in the resin medium around the sensing component and the complete fit between the medium and the sensor. Partial Discharge. This paper describes the modeling and simulation analysis of the designed sensor using the finite element software COMSOL multiphysics, and the performance of the sensor in terms of electric field distribution is optimized through modeling.

Self-Calibration Sensor for Contactless Voltage Measurement Based on Dynamic Capacitance.

Noncontact voltage measurement has the advantages of simple handling, high construction safety, and not being affected by line insulation. However, in practical measurement of noncontact voltage, sensor gain is affected by wire diameter, wire insulation material, and relative position deviation. At the same time, it is also subject to interference from interphase or peripheral coupling electric fields. This paper proposes a noncontact voltage measurement self-calibration method based on dynamic capacitance, which realizes self-calibration of sensor gain through unknown line voltage to be measured. Firstly, the basic principle of the self-calibration method for noncontact voltage measurement based on dynamic capacitance is introduced. Subsequently, the sensor model and parameters were optimized through error analysis and simulation research. Based on this, a sensor prototype and remote dynamic capacitance control unit that can shield against interference are developed. Finally, the accuracy test, anti-interference ability test, and line adaptability test of the sensor prototype were conducted. The accuracy test showed that the maximum relative error of voltage amplitude was 0.89%, and the phase relative error was 1.57%. The anti-interference ability test showed that the error offset was 0.25% when there were interference sources. The line adaptability test shows that the maximum relative error in testing different types of lines is 1.01%.

Self-Calibration Method of Noncontact AC Voltage Measurement

Realizing stable and reliable monitoring of a distribution network voltage environment can obtain real-time power parameter information and ensure the normal and safe operation of transmission lines, which is of great research significance and engineering value. Based on the distributed capacitance relationship between sensor and transmission line, an equivalent circuit capacitance voltage dividing model is proposed, and the relevant factors affecting the stability of the voltage dividing ratio are analyzed. The self-calibration principle of noncontact AC voltage measurement is proposed based on the system identification theory. The noncontact sensing structure is designed, a sensor probe prototype is fabricated, and a back-end conditioning circuit is designed to realize the overall measurement system. Finally, the validity of the measurement model is verified by simulation and experiment, and a measurement platform is built which proves the feasibility of the self-calibration method for noncontact voltage measurement. The experimental results show that the error is less than ±2%. This method can correctly restore the measured voltage waveform, has good linearity, and can realize wireless data transmission, which provides a new idea for the voltage measurement method of a distribution network.

Wideband Noncontact Voltage Measurement for EMC Applications: Design and Implementation

A methodology of amplitude and phase compensation for non-contact voltage measurements, which can be applied to wideband signal and noise observation in the EMC application, is presented. The non-contact techniques are based on a small amount of coupling capacitance between probe electrode and cable conductor where the observed signal is induced. In this case, a main technical issue to be overcome is the amplitude and phase error introduced by stray capacitance of the internal circuit, which needs to be resolved for application of the wideband EMC measurements. Herein, a design and implementation of phase compensation with inverting OpA configuration are discussed. Moreover, by introducing a system calibration with numerical process, validity for recovering the frequency response at 100 Hz ~ 100 MHz is indicated. In the calibration process, frequency compensation for dielectric dispersion of the PVC cable is also discussed. As for the time-domain measurement, the evaluation result of the fast transient impulsive noise of tr/tf: 10 ns emitted from a commercial power supply module is also discussed.

Advanced Dual-Probes Noncontact Voltage Measurement Approach for AC/DC Power Transmission Wire Based on the Electric Field Radiation Principle

Advanced Dual-Probes Noncontact Voltage Measurement Approach for AC/DC Power Transmission Wire Based on the Electric Field Radiation Principle

Non - contact voltage estimation method based on power frequency electric field sensor

The existing non-contact voltage measurement methods are advanced because of their high insulation, safety and reliability, but the distance between the sensor and the transmission line is difficult to measure. Therefore, a non-contact voltage estimation method based on power frequency electric field sensor is proposed. The two factors that lead to the estimation error, sensor consistency and sensor arrangement, are studied by finite element simulation and experiment based on this method. The development of the prototype has also been completed, and its feasibility has been verified through experiments. The experimental results show that the device can be applied to single transmission line voltage measurement. And the maximum estimation error is only 4.12 kV at 38 kV voltage, which proves that this method has high accuracy.

Non-contact Voltage Measurement Technique for On-Line Monitoring of Transient Overvoltages

The electric power system is continuously growing in its size, complexity and required reliability. There is an increased risk due to transient overvoltages which can deteriorate the insulation for different power system components. There is a need for monitoring of transient voltages to better monitor the effects due to them on the insulation of the components. It can be achieved using a non-contact voltage measurement technique. The study elucidates the theory and practical application of the non-contact voltage measurements. The measurement of voltage is achieved by utilizing the stray parasitic capacitance between the high voltage conductor and the ground. A metal plate is used as a sensor to detect the voltage, which indirectly acts as a capacitance divider for voltage measurement. The current study uses operational amplifier based differential-integrator circuit topology in order to accurately measure the voltage over a wide bandwidth of 20 Hz - 1 MHz. The measurement technique is used for measurement of three phase voltages and a methodology is proposed for it. The sensor system is also tested in an online test scenario in a substation for monitoring the shunt reactor switching transients.

Non-intrusive DC voltage measurement based on resonant electric field microsensors

Based on the resonant electric field microsensors with coplanar electrodes, a novel non-intrusive measurement scheme of DC power-line voltage suitable for actual product is presented in this paper. Compared with using microsensors directly without some protection, employing the proposed scheme can avoid the influence of humidity and electromagnetic disturbance on non-contact voltage measurement. A theoretical model is developed to analyze the influence of the structural parameters of the proposed measurement scheme on its sensitivity and to predict the voltage response. Furthermore, the theoretical analysis reveals that the proposed scheme obtains the DC power-line voltage non-intrusively by measuring the voltage of a floating electrode. A prototype of the non-intrusive measurement apparatus of DC power-line voltage has been developed, calibrated, and tested. The prototype shows a favorable linear response characteristic with a linearity of 0.86%. And the experimental results are in good agreement with the theoretical results. The maximum relative deviation noticed is −2.16% over a range of voltages from −1000 V to 1000 V.

Non‐contact voltage measurement of three‐phase overhead transmission line based on electric field inverse calculation

With the development of smart grid, the demand for voltage measurement along the overhead transmission lines is increasing. However, the installation of voltage transformers in the existing lines entails numerous difficulties. This study proposes a new non-contact measurement method by inversely calculating the voltages on AC overhead transmission lines based on the power-frequency electric field measurement data. To improve the calculation accuracy, the 3D model of transmission lines is built, and the relations between the 3D electric fields and voltages are presented. An improved algorithm that intermingles with the particle swarm algorithm and genetic algorithm is developed to ascertain optimal inverse solutions, meanwhile to improve the convergence speed and calculation stability. To further reduce the computational complexity, the constraint relations between the voltages and electric fields are derived, thereby the simplification from three decision variables to one is achieved. Then, some simulation cases with different measurement errors and voltage running states are conducted to show the good robustness and high accuracy of the proposed inversion method. Finally, a three-phase experimental system is built and the actual measured data are used to inversely calculate, which verifies the practicability of the proposed non-contact voltage measurement method.

Research on the Algorithm and Test of Transmission Line Voltage Measurement Based on Electric Field Integral Method

The non-contact voltage measurement of the transmission line is of importance to the operation and intellectualization of the electrical power system. Presently, the non-contact measurement of the transmission line voltage based on the field sensor has been widely studied. The methods of obtaining the voltage by solving the electric field inverse problem have difficulties in solution and calibration. This problem can be effectively solved by adopting the numerical integral algorithm of electric field. In this paper, the voltage measurement by using the Chebyshev piecewise integral algorithm, Gauss-Legendre integral algorithm and Gauss-Legendre improved algorithm was analyzed and the integral intervals of the algorithms were optimized. The multi-index comprehensive evaluation model was established for evaluating the measurement effect, adopting improved subjective weighting method. The finite element simulation model of the 10-kV transmission line was built with the Maxwell software platform to carry out the simulation test. The measurement effects of different voltage measurement methods were compared and it was proposed to apply the Chebyshev piecewise integral algorithm to the voltage measurement system of the transmission line. Finally, the transmission line voltage measurement test platform based on D-dot sensor was built and the measurement safety and accuracy of the Chebyshev piecewise integral algorithm was verified.

Locating of normal transitions in a Bi2223 high temperature superconducting coil by non-contact voltage measurement method

Locating of normal transitions in high temperature superconducting (HTS) coils is important for protection and safety design of HTS apparatus. A general method to locate the normal transitions is to measure resistive voltages along HTS windings by many voltage taps directly soldered to the HTS coils. However, electrical insulation characteristics of the HTS coils are deteriorated because it is necessary to remove electrical insulations of the HTS wires for the soldering. It is a serious problem especially for AC HTS coils to which high voltages are applied. Therefore the authors have presented a non-contact voltage measurement method that can detect the resistive voltages without removing the insulations by voltage dividing capacitors. So far the authors have verified the principle of the non-contact method. In this paper, a method to locate the normal transitions in a Bi2223 HTS coil based on the non-contact method is proposed. The proposed method can not only detect the normal transitions but also locate their positions. It is experimentally confirmed that the proposed method is useful for locating the normal transitions.

Non-contact voltage measurement using electronically varying capacitance

A voltage measurement methodology is presented, based on the principle of a vibrating capacitance, but implemented electronically. A transconductor with time-varying gain synthesises the vibrating capacitance, the peak to peak charge current of which changes as different DC voltages are applied to the capacitively coupled input. This technique allows for the non-invasive measurement of DC voltages. Experimental results show that the amplitude of the output signal can indeed be used to determine input voltage, with the response being dependent upon the capacitance values in the circuit and the frequency of a locally applied signal that is independent of the voltage being measured.