JPH0613531Y2 - Power supply for dew condensation prevention device using electronic dehumidifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a power supply device for a dew condensation prevention device using an electronic dehumidifier that uses a high-voltage current as a drive power supply.

<Prior art> Recently, an electronic dehumidifier has been installed inside a closed switchboard or the like in order to prevent condensation in the rainy season and winter and improve reliability of electric equipment stored inside the switchboard or switchboard. It has become common practice to dehumidify and prevent dew condensation inside the panel, and it has also come to be attached to a conventional existing closed switchboard.

<Problems to be solved by the device> Since the electronic dehumidifier can dehumidify only by applying a direct current to the electronic cooling element utilizing the Peltier effect,
100V AC of commercial frequency for general closed switchboards, etc.
Since the power supply was easily obtained, the auxiliary power supply could be easily prepared by stepping down the voltage to several volts with a small step-down transformer or voltage transformer, and the electronic dehumidifier was applicable. However, in a high-voltage closed switchboard or the like that handles a high voltage of 6.6 KV or more, for example, it is installed on the side of a road for underground power distribution in the city. Since there is no need to install a low-voltage power supply in a high-voltage multi-circuit switchgear box that is composed of only high-voltage electric wires and a group of high-voltage switches, the low-voltage power supply is rarely pre-wired and the existing In order to install an electronic dehumidifier inside a high-voltage closed switchboard of a kind, a power failure occurs and the power is cut off from the high-voltage power line, and a new transformer or high-voltage transformer is used to step down the voltage or a low-voltage line is laid from elsewhere There was nothing else. However, transformers or high-voltage transformers where the primary side has a high voltage and the secondary side has a low voltage, the insulation layer between the primary and secondary sides is extremely large, so it is expensive, requires a large shape, and requires a large installation space. In addition, because of the high voltage, there is a problem in that the power must be cut off for safety and installation work and other work must be performed, resulting in high cost.

<Means for Solving the Problem> However, since the electronic cooling element of the electronic dehumidifier is sufficient to obtain a direct current voltage of several volts and a direct current of several amperes, a large and expensive transformer or high voltage Instead of a transformer, a split-through type saturation current transformer is used, and its secondary current is used as a power source for an electronic dehumidifier.

<Operation> The split-through current transformer is composed of a two-divided iron core with a secondary winding, and a high-voltage wire is sandwiched in the central opening as the primary side to induce the secondary winding. The secondary current thus generated is terminated by a dummy resistor and converted into a voltage source, and the current is directly supplied from both ends of the resistor to the electronic cooling element via the rectifier circuit.
The current transformer is originally a power source for the current source, and the secondary current is proportional to the primary current.However, when the primary current exceeds a certain value, the saturated current transformer saturates the secondary side to obtain a saturation current close to a constant value. You can Therefore, by supplying this saturated secondary current to the dummy resistor, the output can be used as a voltage source of a substantially constant voltage. In this case as well, when the primary current drops below the saturation current value, the output voltage also drops, so the dehumidifying ability of the electronic cooling element also drops. However, since the high-voltage path is generally branched into several loads, it is statistically rare that the primary-side current is close to no load during normal operation, and it is about one half of the primary rated current value. A saturated current transformer that saturates at a value of is sufficient.

<Embodiment> FIG. 1 is a cut-away side view of the whole construction of an embodiment in which the present invention is applied as a power source for a dew condensation preventing device using an electronic dehumidifier installed in a high-voltage multi-circuit branch switch box. FIG. 2 is an enlarged electrical connection diagram showing the portion connecting the output of the current transformer to the electronic dehumidifier, and FIG. 3 shows the split-through type saturated current transformer used in the present invention in the high-voltage multi-circuit branch switch box. FIG. 6 is a schematic perspective view showing an example of a situation in which the main electric wire is sandwiched in a live state. The configuration and operation of the present invention will be described below based on the embodiments shown in these drawings. In addition, the same components are denoted by the same reference numerals throughout FIGS. 1 to 3.

In FIG. 1, reference numeral 10 is a closed switchboard, which is an electric wire (cable) 13 for a circuit that branches off from a high-voltage trunk line 11 for urban underground distribution.
And a group of its switches 14 groups, the electric wire is the inlet 51
Has been laid extending from the underground tunnel. Electronic dehumidifier
30 is installed on the inner wall surface near the high-voltage main line (inlet) 11, is connected to the split-through type saturation current transformer 20 sandwiched between the high-voltage main line (inlet) 11, and is supplied with power. Here, 32 is a drain hose and 52 is a drain. The split through type saturation current transformer 20 is a circular iron core divided into two as shown in FIG. 3 and a secondary winding 22 is applied to each of them.
Since it is molded by 27 and the handle 26 is provided, the high-voltage main line (entrance) 11 is sandwiched in the opening in the center of the iron core, and the lock band 26 provided at the end of the handle is attached to the other end of the handle. By stopping and fixing, the primary wire 21 of the saturation current transformer 20 is obtained. The secondary winding 22 is wound around the split core 23 and connected to the output terminal 25, and the dummy resistor 24 is connected to the output terminal.
Is attached and terminated. When the input power terminal 33 of the electronic dehumidifier 30 is connected to the output terminal 25 of the current transformer 20, the second
As shown in the figure, the single-phase fridge rectifier circuit on the electronic dehumidifier 30 side
DC conversion is performed by 32. In the embodiment having such a configuration, if the primary current flowing through the primary electric wire 21 is equal to or higher than the rated saturation current of 200 A of the saturation current transformer 20, the secondary side of the saturation current transformer 20 is always 40 VA (volt / ampere). ) Can be imposed and the rated current is 5 A. Therefore, if a 1.6 Ω (ohm) resistor is used as the dummy resistor 24, the 100W (Watt) DC power required and sufficient to operate the dehumidifier 30
Can be obtained.

<Effect of the device> Since the split-through type saturation current transformer selected based on the rating of the electronic dehumidifier is sandwiched between the live high voltage wires to serve as the driving power source for the electronic dehumidifier, it is currently in operation. It is possible to immediately install a dew condensation prevention device that uses an electronic dehumidifier on a high-voltage closed switchboard that does not have a low-voltage power supply, and it is not only necessary to cut off the high-voltage line for installation, but Since it is not necessary to newly install an expensive, large-scale transformer or high-voltage transformer for converting to a low voltage in the panel, it is possible to use the existing space to obtain an auxiliary power source at a lower cost and It is effective for improving reliability and reducing costs.

[Brief description of drawings]

FIG. 1 is a cut-away side view showing an embodiment of the present invention applied to a high-voltage multi-circuit branch switch box, and FIG. 2 is an electrical connection diagram.
FIG. 3 is a perspective view showing a situation in which a split type current transformer is attached to a high voltage electric wire. 10 …… High voltage closed switchboard 11 …… High voltage main line (entrance) 12 …… High voltage main line (exit) 13 …… High voltage branch line 14 …… High voltage switch 15 …… Door / handle 20 …… Split through type saturated Current transformer 21 …… Primary electric wire, 22 …… Secondary winding 23 …… Split core, 24 …… Dummy resistor 25 …… Current transformer output terminal, 26 …… Grip 26 …… Lock band, 27 …… Insulation Material 30 ... Electronic dehumidifier 31 ... Single-phase bridge rectifier circuit 32 ... Drain hose, 33 ... Input power supply terminal 34 ... DC power supply output terminal 50 ... Ground surface, 51 ... Underground wire inlet 52 ... … Drainage

Claims (1)

[Scope of utility model registration request] 1. An electronic dehumidifier comprising an electric wire to which a high-voltage current is applied, a split-through type saturation current transformer sandwiching the electric wire, and a dummy resistor connected to the output terminal of the current transformer. Power supply for dew condensation prevention device