JPS62214363A - Fitting structure for voltage sensor - Google Patents

Abstract

PURPOSE:To eliminate the adverse influence from a charged body and a grounded body which are present nearby and to secure initial settings accurately at any time by arranging a detection part composed of a detection electrode and a shield electrode opposite an electrostatic charging part such as a conductor in a totally enclosed switch. CONSTITUTION:The detection part 15 consists of the detection electrode 23 which collects displacement currents flowing in from electrostatic charging parts such as conductor rods 10u, 10v, and 10w through a space and a case 17 which covers the electrode 23 except a displacement current flowing-in part 21 to the electrode 23 and serves as a shield electrode held at a reference potential point. The detection part 15 is arranged in the totally enclosed switch 1 opposite the conductor rods 10u, 10v, and 10w. Consequently, the entry of rain, soiling by the outside air, and damages caused by birds and animals are eliminated and a switch case is grounded, so adjustments of respective phase residuals in initial setting and adjustment and the setting of an output are facilitated and also held constant.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a mounting M4)N of a voltage sensor.

(Prior Art) Conventionally, a voltage sensor for detecting alternating current voltage is generally used at a commercial frequency using a potential transformer (hereinafter referred to as PT).
, or a capacitor voltage division type potential transformer (hereinafter referred to as PD), and in recent years, in addition to PT, devices applying optoelectronic technology have been proposed.

The optoelectronic technology is called a measurement lunar transformer (hereinafter referred to as optical PT), and many of them are being researched.

This light PT is obtained by placing an element with the Pockels effect in an electric field and making straight sunlight incident on it in the same direction as the electric field.
The refractive index for the orthogonal two components shows different changes depending on the electric field strength, and the propagation speed also differs, as a result,
This method takes advantage of the fact that a phase difference occurs between two orthogonal components of light, and the emitted light becomes elliptically polarized light.

The conventional PT or PD as mentioned above is a contact type that is attached directly to the charged part of the cable etc. for the distribution line, so it is not only necessary to consider insulation, but also the PT, P
In D, coil, iron core.

Since a capacitor or the like is used, there is a problem that the whole device becomes large and heavy, and therefore, there is a problem that the installation work is time-consuming.

In addition, optical PT is a non-contact type, and although it has excellent insulation properties, it requires a laser oscillator or the like to convert linearly polarized light, and there is a problem that the entire device is expensive.

Therefore, a detection method that utilizes a displacement current flowing from the charging section through a space has been developed as a method that can be easily driven and downsized.

(Problems to be Solved by the Invention) In this type of non-contact type voltage sensor that uses displacement current through the space, initial settings such as adjusting the residual amount of each phase in the arrangement and maintaining a constant output are important. This is a serious issue.

An object of the present invention is to provide a voltage sensor mounting structure that can always ensure accurate initial settings without being adversely affected by nearby charged or grounded objects when arranging the voltage sensor. .

Structure of the Invention (Means for Solving the Problems) This invention eliminates the detection electrode that collects the displacement current flowing from the charged part through the space, and the displacement current inflow part of the detection electrode. A voltage sensor is composed of a detection section consisting of a shield electrode arranged to cover the ground and kept at a reference potential point, and a signal processing circuit electrically connected to the detection section, and at least the detection section of the voltage sensor The gist is a mounting structure for a voltage sensor that is disposed in a fully enclosed switch facing a charged part such as a conductor rod.

(Function) By installing a voltage sensor inside an existing power distribution device such as a fully enclosed switch, there is a risk of intrusion of rainwater, contamination by outside air, damage from birds and animals, and the fact that the switch case is grounded. When adjusting initial settings. The residual amount adjustment and output settings for each phase can be easily carried out, and are always kept constant, and are not affected by grounding objects such as concrete pillars when installing poles, so that the initial settings are not affected. Nor.

(Example) Hereinafter, a first example in which the present invention is embodied in a voltage sensor of a zero-phase voltage detection device will be described with reference to FIGS. 1 to 7.

The case 2 of the fully enclosed switch 1 is composed of a main body case 3 and a bottom cover 4 that is tightly attached to the bottom surface of the main body case 3 via a gasket, and a ground terminal 7 is provided on the top surface of the main body case 3.
The case 2 is grounded via the ground terminal 7 when mounted on a pole.

Furthermore, bushings 8 and 9 are fixed through each side of the case 2 for each phase. Conductive rods 10 and 11 as charging parts are fitted into each bushing 8.9, and conductive rods 10u and 10v on the power source side.

A fixed electrode 12 is fixed to 10w, and a movable electrode 13 corresponding to the fixed electrode 12 is connected to each of the load-side conductor rods 11u, Ilv, 11w so as to be able to move toward and away from the fixed electrode 12. The distribution line can be opened and closed by rotating the movable electrode 13 using the opening and closing mechanism.

Above the bushing 8 on each power supply side, voltage sensors 3u, 3v, and 3w of a zero-phase voltage detection device are mounted at a fixed interval with respect to the bushing 8 of each phase by sensor mounting members 14 for each phase against the inner surface of the switch case 2. It's well placed.

A detailed explanation of the voltage sensors Su, Sv, and Sw is as follows:
The voltage sensors 3u, 3v, and 3W are composed of a detection section 15 and a signal processing circuit 16.

The case 17 of the detection unit 15 is formed into a channel-like cross section, and mounting pieces 18 are formed at both ends of the side walls facing each other and at both ends of the bottom wall, respectively, to be bent inward at right angles. A lid 19 formed in a reverse channel shape is fixed to the mounting piece 18 of the case 17 by soldering or the like so as to cover both end openings and the lower part of the case 17, and a lid 19 is fixed to the mounting piece 18 of the case 17 by soldering or the like for each phase. Window 2 as a displacement current inflow part having a square shape
1 is transparent. The case 17 and the lid 19 are made of a conductive material such as aluminum, and a detection electrode 2 to be described later.
In order to effectively prevent the inflow of displacement current from sources other than the conductor rods 10u, 10v, and 10w, which are the objects to be measured, the conductor rods 10u, 10u, which are the objects to be measured,
Other conductor rods other than 10v and 10w iQu, 10v, 1
There is virtually no negative effect of 0w.

A flat detection electrode 23 is fixed to the central lower surface of the case 17 via an insulating support member 22 made of an insulating material such as synthetic resin. This detection electrode 23 is arranged parallel to M2O and is covered with the case 17 and the lid 19 except for the window 21. Further, insulating plates 22a are provided on the upper and lower sides of the outer surface of the insulating support member 22, and a board 24 incorporating the signal processing circuit 16 is built into the insulating support member 22. It is possible to prevent the surface leakage resistance of the portion 22 from decreasing.

In addition, since the substrate 24 incorporating the signal processing circuit 16 is built into the insulating support member 22 and covered with a shield N pole, there is no adverse effect such as disturbances from sources other than the object to be measured, that is, the conductor rods 10u, 10v, and 10w. The displacement current from the object to be measured can be accurately detected. Moreover, the signal processing circuit 16
may be placed outside as long as it is adequately shielded.

A slide plate 25 for adjusting the opening area of the window 21 is placed around the window 21 so as to overlap M2O, and the poles 1 to 26 and their bolts 26 passing through both 25 and 19 are arranged around the window 21.
It is attached by a thumbscrew 27 that is screwed into the. and,
The slide plate 25 slides along an elongated hole 28 formed in the mounting 19 and through which a bolt 26 passes, and by tightening a wing screw 27, the slide plate 25 can be fixed at an appropriate location.

Therefore, the detection electrode 23 can change the opening area of the window 21 as appropriate, and provides an opening for adjusting the three-dimensional opening angle of the detection electrode 23 with respect to the window 21, that is, the solid angle e. Even if the ground voltage of each phase is balanced due to the inflow of displacement currents of other phases with different phases into the voltage sensor S, a zero-phase output is generated at the output terminal P. When adjusting S, the thumbscrew 27 of the voltage sensor S is rotated to move the slide plate 25 to adjust the frontage area of the agreement 21, that is, adjust the solid angle e, so that the zero-phase voltage It can be adjusted to be as close to zero as possible. In addition,
The detection electrode 23 is made of a conductive material such as metal, conductive resin, or conductive rubber, and in this embodiment, aluminum, which is easy to process, is used.

The detection section 15 is constituted by the case 17, M2O, the detection electrode 23, and the insulating support member 22.

The detection electrode 23 is connected to the input terminal P1 of the substrate 24, and a displacement current is input to the input terminal P1. Further, this board 24 is connected via a lead wire 29 to a power supply circuit 33 of a power supply section installed on a part of a utility pole outside the switch 1. Similarly, the shield electrode of the voltage sensor S is also connected to a ground line E1 via a terminal P2 (described later) of the substrate 24 by a lead wire 31. Note that it is desirable to cover the lead wire 29 with a shield so that it is not affected by external disturbances.

To explain the signal processing circuit 16 on the board 24, the signal processing circuit 16 is roughly divided into an amplifier circuit A, a bandpass filter circuit B, etc.).

When the displacement current is input from the detection electrode 23, the amplifier circuit A amplifies the displacement current and outputs a waveform similar to the displacement current. Specifically, the amplifier circuit A is configured as follows. That is, the input terminal P of the signal processing circuit 16
1 is connected to ground 151E1 via resistor R1. Further, a parallel circuit of a pair of diodes Di, 02 facing oppositely to each other is connected between both terminals of the resistor R1, so that the detection electrode 23 is connected to the excessive l! This is a protection circuit to block current input.

The input terminal P1 is connected to an operational amplifier 9 OP via a resistor R2.
It is connected to the inverting input terminal of the same operational amplifier OP.
The non-inverting input terminal of No. 1 is connected to the ground line E1 via a resistor R3. A parallel circuit of a capacitor C1 and a resistor R4 is connected between the inverting input terminal and the output terminal of the operational amplifier OP1. Bandpass filter B is set to selectively amplify and extract the frequency 60H2 or 50Hz based on the center frequency when a signal similar to the displacement current is applied. Specifically, the following It is configured as follows.

In other words, the output terminal of operational amplifier OP1 and operational amplifier ○
A series circuit of a capacitor C6 and a resistor R5 is connected between the inverting input terminal of P2, and the non-inverting input terminal of the operational amplifier OP2 is connected to the ground line E1 via a resistor R6. A series circuit of capacitors C4 and C5 and resistors R7 and R are connected between the inverting input terminal and the output terminal of the operational amplifier OP2.
A parallel circuit consisting of 8 series circuits is connected. Further, a capacitor C7 is connected between a point a between the resistors R7 and R8 and the ground line E1.

Here, an example of a zero-phase voltage detection device using the voltage sensors 3u, 3v, and 3w will be described. Voltage sensors Su are arranged corresponding to the respective phases.

3v, 3w, an addition section and a power supply section provided outside the switch 1 constitute a zero-phase voltage detection device.

To explain the power supply circuit 33 of the power supply section, 100VA
A power transformer 34 is connected to the C power terminal, and a full-wave rectifier 35 is connected to the secondary side of the power transformer 34.

The point d on the secondary side of the power transformer 34 is connected to the ground wire E2.
A smoothing capacitor C14 and a capacitor C15 are connected between the positive terminal of the full-wave rectifier 35 and the ground line E2.

Further, a three-terminal regulator 36 is connected between the positive terminal of the full-wave rectifier 35 and the ground wire E2, and the output terminal of the three-terminal regulator 36 is connected to the +v cci terminal, and the output terminal of the three-terminal regulator 36 is connected to the +vcci terminal. Ground wire E2
A capacitor C8 and a capacitor C9 are connected between them.

Furthermore, a smoothing capacitor C10 and a capacitor C11 are connected between the negative terminal of the full-wave rectifier 35 and the ground wire E2. Moreover, a three-terminal regulator 37 is connected between the negative terminal of the full-wave rectifier 35 and the ground wire E2,
The output terminal of the three-terminal regulator 37 is connected to the -VCC terminal, and a capacitor C12 and a capacitor C13 are connected between the output terminal of the three-terminal regulator 37 and the ground line E2.

The addition circuit 40 constituting the addition section connects each voltage sensor Su.
, Sv, Sw signal processing circuits 16 output from the signal processing circuits 16, selected at a predetermined frequency, are synthesized and a zero-phase voltage signal is output to the output terminal P3. Specifically, each voltage sensor Su is connected to the inverting input terminal of the operational amplifier OP3.

The output terminal P of a 3V, 3W signal processing circuit 16 is connected, and its non-inverting input terminal is grounded via a resistor R10. The output terminal of operational amplifier OP3 is resistor R11.
It is connected to the inverting input terminal of the operational amplifier OP3 via the same. Further, the output terminal of the operational amplifier OP3 is connected to the output terminal P3 via an operational amplifier OP4 as a voltage follower and a resistor R12.

An adder circuit 40 is constituted by the resistors R10 to R12 and the operational amplifier OP3°OR3.

Now, the operation of the zero-sequence voltage detection device configured as above will be explained.

In FIG. 6, a conductor bar 10u for each phase serves as a charging section.

Voltage sensors 3u and Sv correspond to 10V and 10W.

The SWs are spaced apart at approximately the same distance in the store. Conductor rod 1
When a three-phase voltage according to normal phase rotation is applied to 0u, 10v, and 10w and a steady load current is flowing, a voltage is formed between the conductor rods 10u, 10v, and 10w and the ground, which is the reference potential point, respectively. The displacement current flowing through the capacitors ICU, cv, and cw is collected by each detection electrode 23 through the voltage sensor 21 of each phase voltage sensor Su, 3v, and 3w as a displacement current inflow portion.

This displacement current is then applied to the amplifier circuit A of the substrate 24, which amplifies the displacement current and outputs a waveform similar to the displacement current to the bandpass filter B. In this case, the input impedance seen from terminals Pi and P2 is the resistance R
1 and resistor R2 in parallel. As is well known, in typical applications of operational amplifiers, the resistance R2 has a value on the order of Ω. Further, the closed loop gain R4/R2 is set to about 1000 in order to obtain a sufficient output.

Therefore, the input impedance mentioned above is effectively kept at a sufficiently low value by the resistor R2, yet a large signal is available at the output of the operational amplifier OP1 due to the high closed-loop gain. As is well known, the phase difference between the input and output of the culm amplifier OP1 changes depending on the magnitude relationship between the impedances of the resistor R4 and the capacitor C1, and if the former is relatively small, the phase difference is ignored and the output is proportional to the displacement current. is obtained. In the opposite case, the phase difference is close to 90', and the output is an integral value of the displacement current, that is, a value proportional to the potential of the conductor rod as the charging portion. In any case, this output has a waveform similar to the displacement current.

Next, when a signal similar to the displacement current is applied to the bandpass filter B, the frequency (301-(
A signal having a center frequency of z or 501-IZ is selectively amplified and taken out, and the outputs of each phase outputted to the output terminal P are combined to output a signal multiplied by the zero-phase voltage VO (see FIG. 7). In this Fig. 7, α, β, and γ are each conductor rod 10u.
, 10v, and 10w. In this way, in normal cases, the ground voltages of each phase are balanced, so the resulting zero-sequence voltage VO is O.

Next, if a ground fault occurs in the distribution line of one of the phases of the conductor rods 10u, 10v, and 10w, the balance between the ground voltages of each phase will be disrupted. A zero-phase voltage is detected at the terminal P3 by combining the displacement currents.

As a result, it is detected that a ground fault has occurred in the power distribution line.

Next, a second embodiment will be explained with reference to FIG.

In this embodiment, the voltage sensors 3u, SV, and 3w for each phase of the second embodiment are not necessarily located at the upper position, but the conductor rods 1 on both sides.
The difference between 0u and 10w is that the voltage sensors 3u and 3w are respectively disposed on the sides of the bushing 8. Further, both voltage sensors Su and sw may be arranged at the corners of the switch case 2.

Next, a third embodiment will be described with reference to FIG.

In this embodiment, an upper lid type switch is implemented, and voltage sensors 3u, 3v, 3w are connected to the main body case 3 compared to the first embodiment.
7 in that it is disposed near the top lid 38, and when adjusting the solid angle e, the adjustment can be easily performed with the top lid 38 open. It is also possible to arrange voltage sensors Su, Sv, and SW on the upper M38.

Similarly, when the fourth embodiment is explained according to FIG.
Even in the case of a bottom cover type switch similar to the embodiment, the main body case 3
Voltage sensors Su, Sv, 3w are placed near the bottom M4 of
By arranging the solid angle e, the solid angle e can be easily adjusted.

The fifth embodiment will be explained according to FIG. 11. Compared to the first embodiment, this embodiment has a bushing 8 in the case 2.
An insulation barrier 39 is provided between the phase voltage sensors Su, Sv, and SW, and the phase voltage sensors su, Sv, and S
The difference is that the shield electrode of w is directly connected to case 2 of switch 1 and grounded. At this time, by bending the tip of the insulating barrier 39 downward, dew condensation water generated on the barrier 39 can be caused to flow and the capacitance can be stabilized.

Note that the present invention is not limited to the above embodiments, and the voltage sensors 3u, Sv, and Sw can be installed at appropriate locations within the case 2, and the voltage sensors S for each phase can be installed at appropriate locations within the case 2.
u, Sv, and Sw can be installed either on the power supply side or the load side. Also, voltage sensors Su, Sv, sw
This can be done without providing the insulation barrier 39 by using resin molding or the like if the dielectric strength allows.

Next, a sixth embodiment will be described with reference to FIG.

In this embodiment, the detection section of the voltage sensor S is used for a zero-phase voltage detection device, and the detection electrode is common to three phases, and only the differences from the previous embodiment will be described.

Detection electrode 2 common to all phases in one case 17 and n19
3, and the lid 19 has three windows 2 for each phase.
1, a substrate 24 incorporating a signal processing circuit 16 is housed in an insulating support member 22.

Effects of the Invention As detailed above, in the voltage detection method that utilizes the displacement current flowing from the charging member through space, the voltage sensor is placed at a position corresponding to the conductor bar on the power supply side, so that voltage is constantly applied. Since the zero-sequence voltage can be measured at all times, it is necessary to set the normal zero-sequence voltage to O. This prevents water from entering, contamination from outside air, damage from birds and animals, and concrete-1 to pillar-F.
This ensures stable detection operation at all times without being affected by any external influences. Furthermore, the detection section can be mounted within the space where the switch is held on the pillar, and has an excellent effect in that no separate space is required.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a switch according to a first embodiment of the present invention;
The figure is a cross-sectional view of the switch, Figure 3 is an exploded perspective view of the voltage sensor, Figure 4 is an electric circuit diagram of the amplifier circuit and filter of the voltage sensor, and Figure 5 is an electric circuit diagram of the power supply circuit of the power supply device. , Fig. 6a is a conceptual diagram of the voltage sensor of the zero-phase voltage detection device;
The figure shows an electric circuit diagram of the addition circuit of the addition section, Figure 7 shows the zero-sequence voltage detected by this zero-phase voltage detection device and the voltage oscilloscope of each conductor bar, and Figure 8 shows the opening and closing of the second embodiment. 9 is a longitudinal sectional view of the switch of the third embodiment, FIG. 10 is a longitudinal sectional view of the switch of the fourth embodiment, and FIG. 11 is a longitudinal sectional view of the switch of the fifth embodiment. FIG. 12, a partially sectional view, is a conceptual diagram of a zero-phase voltage detection device of a sixth embodiment. 1... Switch, 2... Switch case, 10u, 10
v, iQw... Conductor rod (charged part), 15... Detection part, 16... Signal processing circuit, 17... Case (shield electrode), 19... Lid (shield electric tffi), 21
...Window (displacement current inflow part), 23...Detection electrode, A
...Amplification circuit, B...Band pass filter, El,
E2...Grounding wire, OP1~OP4...Bullet amplifier,
R1-R12...Resistor, C1-C13...Capacitor, P...Output terminal, Pl...Input terminal, P2...
・Terminal, P3... Output terminal, Cu, Cv, Cvv-・
・Each electrostatic group, S, Su, Sv. SW...voltage sensor. Patent applicant Nippon Insulator Co., Ltd. Takamatsu Electric Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A detection electrode that collects the displacement current flowing from the charged part through the space, and a shield placed to cover the detection electrode except for the displacement current inflow part and kept at the reference potential point. A voltage sensor is composed of a detection part consisting of an electrode and a signal processing circuit electrically connected to the detection part, and at least the detection part of the voltage sensor is connected to a charged part such as a conductor rod in a totally enclosed switch. A voltage sensor mounting structure characterized in that they are arranged facing each other.