CN-121986266-A - Non-contact voltage sensor device

Abstract

A non-contact voltage sensor device is provided with a probe electrode (10) for observing an alternating voltage generated in a cable in a state where the electrode is not connected, the cable having a cable conductor and a coating material coating the cable conductor, an impedance circuit (14) connected to the probe electrode, the impedance circuit having a 1 st resistance element (142) simulating the insulation resistance of the coating material, a 1 st capacitor element (141) simulating the coupling capacitance generated between the cable conductor and the probe electrode, and a dielectric relaxation simulation circuit (143) simulating the dielectric relaxation generated in the coating material, and an operational amplifier (15) having an anode input terminal connected to a reference potential point, a cathode input terminal connected to an input point of the impedance circuit, an output terminal connected to an output point of the impedance circuit, the dielectric relaxation simulation circuit having at least 1 buffer circuit (SC; SC 1-SC 3) having a series connection of 2 nd resistance elements (1431; 51-53) and 2 nd capacitor elements (1432; 61-63).

Inventors

• TAMAKI YUZO
• Ming Xingqingyang

Assignees

• 三菱电机株式会社

Dates

Publication Date

20260505

Application Date

20231012

Claims (5)

1. 1. A non-contact voltage sensor device, having: a probe electrode for observing an alternating voltage generated in a cable having a cable conductor and a coating material coating the cable conductor in a state where electrode connection is not performed; An impedance circuit connected to the probe electrode, the impedance circuit having a1 st resistive element, a1 st capacitor element, and a dielectric relaxation simulation circuit connected in parallel to each other, the 1 st resistive element simulating insulation resistance of the clad material, the 1 st capacitor element simulating coupling capacitance generated between the cable conductor and the probe electrode, the dielectric relaxation simulation circuit simulating dielectric relaxation generated in the clad material, and An operational amplifier connected to the output point of the impedance circuit, the positive input terminal of the operational amplifier being connected to a reference potential point, the negative input terminal of the operational amplifier being connected to the input point of the impedance circuit, the output terminal of the operational amplifier being connected to the output point of the impedance circuit, The dielectric relaxation analog circuit has at least 1 buffer circuit configured such that a2 nd resistive element different from the 1 st resistive element and a2 nd capacitor element different from the 1 st capacitor element are connected in series.
2. 2. The non-contact voltage sensor device according to claim 1, wherein, The at least 1 buffer circuit has a plurality of buffer circuits connected in parallel with each other.
3. 3. The non-contact voltage sensor device according to claim 2, wherein, The dielectric relaxation analog circuit has a sub-switching element connected in series with each buffer circuit, and the sub-switching element is used for switching whether each buffer circuit is connected or not.
4. 4. A non-contact voltage sensor device according to any one of claim 1 to 3, wherein, The 2 nd resistive element includes at least 1 variable resistive element, and the 2 nd capacitor element includes at least 1 variable capacitive element.
5. 5. The non-contact voltage sensor device according to any one of claims 1 to 4, wherein, The impedance circuit also has a main switching element for switching the presence or absence of connection to the dielectric relaxation analog circuit.

Description

Non-contact voltage sensor device Technical Field The present invention relates to a non-contact voltage sensor device. Background Conventionally, there is a technique of observing an ac voltage of a cable core wire without bringing a probe electrode into contact with the cable core wire. In such non-contact observation, since a minute coupling capacitance is generated between the cable core and the probe electrode, each component on the sensor circuit side is in a state of high impedance compared to the coupling capacitance. In this case, if a part of the components on the sensor circuit side has a real part of complex impedance such as an input resistance of an operational amplifier, for example, the phase of the ac voltage waveform to be observed is rotated, and high-precision observation cannot be achieved. To solve the above-described problems, for example, the non-contact voltage sensor device described in patent document 1 includes a frequency compensation circuit that compensates for frequency characteristics of the amplitude and phase of an ac voltage waveform. The frequency compensation circuit is configured to have an impedance circuit and an operational amplifier, and the impedance circuit simulates a complex impedance from the cable core to the input terminal. Thus, even if the coupling capacitance generated between the probe electrode and the cable core is a minute capacitance, the component on the sensor circuit side does not become a high impedance state, and deterioration in accuracy such as phase rotation of the observed waveform can be suppressed. Patent document 1 Japanese patent No. 7003338 Disclosure of Invention However, according to the conventional device, there is a problem that an error caused by the frequency characteristic of the coupling capacitance generated by the effect of dielectric relaxation generated in the coating material coating the cable core is not considered and included in the observed waveform. The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a non-contact voltage sensor device capable of suppressing an error included in an observed waveform as compared with the conventional one. An aspect of the non-contact voltage sensor device according to an embodiment of the present invention includes a probe electrode for observing an alternating voltage generated in a cable having a cable conductor and a coating material coating the cable conductor in a state where the probe electrode is not connected, an impedance circuit connected to the probe electrode, the impedance circuit including a1 st resistor element, a1 st capacitor element, and a dielectric relaxation analog circuit connected in parallel to each other, the 1 st resistor element simulating an insulation resistance of the coating material, the 1 st capacitor element simulating a coupling capacitance generated between the cable conductor and the probe electrode, the dielectric relaxation analog circuit simulating a dielectric relaxation generated between the coating material, and an operational amplifier connected to an output point of the impedance circuit, a positive input terminal of the operational amplifier connected to a reference potential point, a negative input terminal of the operational amplifier connected to an input point of the impedance circuit, an output terminal of the operational amplifier connected to an output point of the impedance circuit, the dielectric relaxation analog circuit including at least a1 st buffer element and a buffer element 2, the buffer element being configured to be different from each other in series from the 1 st buffer element and the buffer element 2. ADVANTAGEOUS EFFECTS OF INVENTION According to the non-contact voltage sensor device of the embodiment of the present invention, since the impedance circuit of the non-contact voltage sensor device has the dielectric relaxation simulation circuit that simulates the dielectric relaxation generated in the coating material, it is possible to suppress errors that may be included in the observed waveform in consideration of the effect of the dielectric relaxation, as compared with the conventional one. Drawings Fig. 1A is a block diagram showing the structure of a noncontact voltage sensor device according to embodiment 1. Fig. 1B is a diagram showing a configuration example of a dielectric relaxation analog circuit according to embodiment 1. Fig. 2 is a graph showing the results of actual measurement and simulation of the frequency characteristics of the non-contact voltage sensor device due to dielectric relaxation. Fig. 3 is a circuit diagram of a non-contact voltage sensor device as a comparative example used in the actual measurement and simulation of fig. 2, which does not have a compensation circuit for dielectric relaxation. Fig. 4 is a circuit diagram showing a configuration of a modification of the dielectric relaxation analog circuit accord