JP2583567Y2 - Separate current collector charge indicator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention is mainly used by attaching to a grounding side of a high voltage device such as a transformer having a special high voltage or more, LS, etc., and detecting whether or not a target high voltage device is in a charged state. The present invention relates to a charging indicator.

[0002]

2. Description of the Related Art A charging indicator is a safety device for displaying on a liquid crystal element that a voltage is applied to a charging section of a substation facility or the like, thereby preventing an accident due to an illusion or an erroneous recognition. The most common conventional charging indicator is integrally formed together with a case in a circuit configuration as shown in FIG. 3, and is used by directly attaching it near a high-voltage charging unit. In FIG. 3, reference numeral 1 denotes a high-voltage charging unit such as a conductor or a substation facility;
9 is the earth. The circuit configuration of the charging indicator 10 is P
A current collecting plate 2 made of two conductive materials 1 and P2; an AC / DC conversion circuit 3; a liquid crystal driving circuit 4;

The two current collecting plates 2 detect an AC electric field around the high voltage charging unit 1 and convert the energy of the electric field into an AC current IA.
(Hereinafter referred to as a current collector plate current) to the AC / DC conversion circuit 3. The AC / DC conversion circuit 3 converts the current collector current IA to DC and supplies it to the liquid crystal drive circuit 4. This DC voltage VD is called a circuit voltage, and its magnitude is determined depending on the current collector current IA. The liquid crystal driving circuit 4 outputs a liquid crystal driving waveform of the voltage VD. If the magnitude of the circuit voltage VD exceeds the display threshold of the liquid crystal element 5, the liquid crystal element 5 is clearly displayed. The conventional charging indicator 10 is adjusted so that when the voltage of the high-voltage charging unit 1 reaches a predetermined rated voltage V.sub.0, the circuit voltage V.sub.D exceeds the display threshold with a margin.

[0004] The charging indicator 10 of the type that is directly attached to the high-voltage charging unit 1 and used must be attached and detached while the operation of the substation equipment is stopped. When used for substation equipment with extra high voltage, these facilities are generally installed several meters above the ground, and the height of the charging section and overhead lines is high.
The display content of 0 becomes difficult to see. There was a disadvantage. Such a drawback can be solved if there is a charging indicator that can be used by being attached to a portion at the ground potential. However, it has not been known at all how to accurately distinguish and display an induced electric field from the other side, such as an LS or CB, and an electric field directly generated by the charging unit to be detected.

[0005] As a result of experiments and measurements, the practical use of the conventional charging indicator 10 with the method of attaching the charging indicator to the ground side is due to the display characteristics of the liquid crystal element and the charging indicator 1.
It has been found that this is impossible from the relationship between the current collector plate current IA of 0 and the characteristics of the circuit voltage VD. This is because, when the conventional charging indicator 10 is attached to the ground side and used, it is inevitable that the indication as to whether or not the charged part to be detected is in a live state is ambiguous. In order to eliminate the above-mentioned defect, the inventor has proposed a voltage which operates the conventional charging indicator 10 so as to perform the liquid crystal display only when the circuit voltage becomes larger than a certain threshold voltage. It has been found that the charging indicator 11 may be configured by adding a determination circuit and a switch circuit.

FIG. 4 shows a charging indicator 11 mounted on the ground side.
3 is a diagram showing an example of the circuit configuration of FIG. 3, and the same parts as those in FIG. 3 are denoted by the same reference numerals. 6 is a voltage discriminating circuit, and 7 is a switch circuit. A description will be given of the operation of each part of the circuit which is particularly different from that described in FIG. Among the two current collectors 2, P1 forms a stray capacitance C1 with the high-voltage charger 1. The current of the current collector IA is the magnitude of C1, in other words, the magnitude of P1. Depends on you. Also, P2 can be omitted because it is directly connected to the ground 9.

The voltage discriminating circuit 6 has a threshold voltage set therein. For example, if the threshold value is set to 2.8 V, when the circuit voltage VD is 2.8 V or less, the output of the voltage discriminating circuit 6 is at the L level and the switch circuit 7 is kept open. Does not join. When the circuit voltage VD exceeds the set threshold value of 2.8 V, the output of the voltage discriminating circuit 6 goes high and the switch circuit 7
Is closed, and a clear liquid crystal display is performed. Therefore, this threshold value is set to the minimum value of the circuit voltage VD reached by the electric field directly generated by the high-voltage charging unit 1 to be detected, and to the other line or L
What is necessary is just to set it at an intermediate value between the maximum value of the circuit voltage VD reached by the induced electric field from the opposite side such as S and CB.

[0008]

However, in the case where the charging indicator 11 having the above structure is integrally formed, inconvenience in use may occur. For example, in the case of a transformer, the most important place to check whether or not a live state is a place where a ladder ascends above the transformer. However, the location of this ladder is generally far from the high voltage bushing of the transformer and is not suitable as an electric field detection site. Also in the case of the LS, when the grounding mechanism is attached, the grounding mechanism may obstruct the display of the charging indicator in some cases. As described above, there is a problem in use when there is no appropriate mounting place for the high-voltage device or when a place where the display contents of the electric field detector and the charging indicator are desired to be separated from each other.

[0009]

According to the present invention, in order to solve the above-mentioned problem in use, a current collecting plate is separated from the components of the charging indicator 11, and the current collecting plate portion 20 is provided with a current collecting plate. The board is insulated, the display unit 30 includes an AC / DC conversion circuit that converts an AC current to a DC current, a liquid crystal drive circuit that outputs a liquid crystal drive waveform with the DC circuit voltage supplied from the AC / DC conversion circuit, A voltage discriminating circuit for outputting the L level when the DC circuit voltage supplied from the AC / DC conversion circuit is equal to or lower than a predetermined threshold voltage and the H level when exceeding the threshold voltage; The coaxial cable 40 is formed by a switch circuit that opens when the output of the discrimination circuit is at L level and closes when the output is at H level, and a liquid crystal element that is displayed when the switch circuit is closed. On board and others There is connected to the input side of the one end of the AC-DC conversion circuit, the other end of the input side of the braided jacket and AC-DC conversion circuit is obtained by the both grounded configuration.

[0010]

The current collecting plate separated type charging indicator of the present invention constructed as described above places the current collecting plate portion at the most suitable location for detecting the electric field on the grounding side of the high voltage equipment, and provides safety for high voltage work and the like. The display unit can be used by attaching it to the most effective place or the most visible place.

[0011]

FIG. 1 is a diagram showing a configuration example of the present invention. The current collector separate charging indicator 12 of the present invention includes three parts: a current collector 20, a display 30, and a coaxial cable 40. The current collecting plate portion 20 is made of an insulating material 21 around the current collecting plate 2 (P1 in FIG. 4).
It is processed so that it is wrapped in. The display unit 30 includes an AC / DC conversion circuit 3, a liquid crystal drive circuit 4, a liquid crystal element 5, a voltage determination circuit 6, and a switch circuit 7. The coaxial cable 40 has one end of a core wire 41 connected to the current collector plate 2 and the other end connected to one end on the input side of the AC / DC conversion circuit 3. Further, the braided jacket 42 of the coaxial cable 40 is grounded together with the other end of the input side of the AC / DC conversion circuit 3. Therefore, the current collector P2 is omitted from the components of the charging indicator 11 shown in FIG.

In FIG. 1, a current collector plate 2 detects an electric field generated by a high-voltage charging section 1 such as a high-voltage bushing via a stray capacitance C1, and uses the energy of the electric field as a current collector current IA as a display section 30. To supply. Its size is about several μA. Therefore, unless the current collector plate 2 is completely insulated, the current of the current collector plate IA easily leaks to the ground in the case of rain or the like, and the display operation becomes uncertain. In this sense, the insulating treatment using the insulating material 21 is important. As the insulation treatment, a method of sealing in a plastic case, a method of molding, and the like are suitable. The coaxial cable 40 is a conductor for transmitting the current IA to the display unit 30. When a mere covered wire is used for this portion, the conductor serves as a current collector, and the current collector current I depends on the surrounding electric field condition.
Upset the size of A. In order to reduce the transmission loss of the coaxial cable 40, a cable having a small capacitance CS between the core wire 41 and the braided jacket 42 is suitable. The operation of the display unit 30 is the same as that described with reference to FIG. 4, and the description thereof is omitted here.

FIG. 2 shows the charging indicator 1 of the present invention with a separate current collector plate.
FIG. 6 is a diagram illustrating an example in which 2 is applied to a transformer 50. The current collector 20 is attached to a flange of the high-pressure bushing 51. The display unit 30 is provided beside the ladder 52 on the opposite side of the high-pressure bushing 51. The coaxial cable 40 connecting both parts is routed on the upper surface of the transformer tank 53. The worker 60 can easily check the display contents of the display unit 30 of the charging plate separation type charging indicator 12 before climbing the ladder 52,
Avoid illusions and misperceptions.

[0014]

[Effects of the Invention] Separate collector plate charging indicator 12 of the present invention
Solves the inconvenience of using the charging indicator 11 which can be used by being attached to the ground side, and greatly contributes to the safety of high-pressure work.

[0015] The current collector separated type charging indicator 12 of the present invention comprises:
If there is a dielectric strength between the current collector plate portion 20 and the coaxial cable 40,
The current collector plate unit 20 is directly attached to the high voltage charging unit 1, and the display unit 3
0 can also be used by placing it on an easily visible place on the ground side. The current collector separated type charging indicator of the present invention can display the strength of the electric field with a certain threshold value, so if it is used by attaching it to each of the three-phase charging parts, it will not be possible with the conventional charging indicator. There is an effect that an accurate missing phase display becomes possible.

[Brief description of the drawings]

FIG. 1 is a view for explaining the configuration and operation of a charge collector separated type charging indicator of the present invention.

FIG. 2 is a diagram showing an example in which the present invention is applied to a transformer.

FIG. 3 is a diagram for explaining the circuit configuration and operation of a conventional charging indicator.

FIG. 4 is a diagram showing a circuit configuration of a charging indicator attachable to the ground side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 Current collector 3 AC / DC conversion circuit 4 Liquid crystal drive circuit 5 Liquid crystal element 6 Voltage discriminating circuit 7 Switch circuit 12 Separate current collector charge indicator of the present invention 20 Current collector plate unit 30 Display unit 40 Coaxial cable 41 Core wire of coaxial cable 42 Braided jacket of coaxial cable

Claims (1)

(57) [Scope of request for utility model registration] 1. A current collector plate for detecting an AC electric field around a high voltage charger, a display for displaying whether or not the high voltage charger is charged, and a connection between the current collector and the display. A charging indicator provided with a coaxial cable, wherein the current collector plate portion is provided with an insulation process on the current collector plate, and the display portion includes an AC / DC conversion circuit for converting an AC current to a DC current; a liquid crystal driving circuit for outputting liquid crystal drive waveform in the DC circuit voltage supplied from the conversion circuit, the AC to DC
A voltage discriminating circuit for outputting the L level when the DC circuit voltage supplied from the conversion circuit is equal to or lower than a preset threshold voltage and the H level when exceeding the threshold voltage, A switch circuit that opens when the output of the voltage discriminating circuit is at L level and closes when the output is at H level, and a liquid crystal element that the switch circuit displays when the circuit is closed, wherein the coaxial cable has one end of a core wire. And the other end is connected to one end on the input side of the AC / DC conversion circuit, respectively, and the braided jacket and the other end of the input side of the AC / DC conversion circuit are both grounded. A separate charging plate charging indicator.