JP2011228102A - Road lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road lamp capable of distributing an alternating current supplied from a transformation facility as-is, even if including an electronic circuit, and suppressing a power distribution loss and a transformer loss.SOLUTION: The road lamp 1 illuminating a road by lights irradiated from a light-emitting portion 10, includes an autotransformer 11 depressing the first voltage of the alternating current supplied from the transformation facility to the second voltage of the alternating current, and a power supply portion 12 having a converting circuit 12a converting the second voltage of the alternating current into a predetermined current voltage form so as to be supplied to the light-emitting portion 10.

Description

  The present invention relates to a road lamp that illuminates a road with light emitted from a light emitting unit.

  Many road lights are installed on ordinary roads and expressways to illuminate the road at night. In many cases, a high-intensity discharge (HID) lamp such as a sodium lamp, a mercury lamp, or a ceramic metal halide lamp is used for the light-emitting portion of these road lights. In recent years, road lights using LEDs that can save energy have also been developed (see, for example, Patent Document 1). In recent years, lighting fixtures have been improved in efficiency by using an electronic lighting device as a lighting device, and an electronic power supply device is also used in an LED road light. However, in the case of an electronic power supply device, it is configured by electronic parts that are generally distributed from the viewpoint of price and size, and it is difficult to cope with a high power supply voltage (for example, 265 V or more).

  FIG. 4 is a diagram schematically showing the flow of power supplied from the electric power company to each road light. The electric power 40 supplied from the electric power company has a high voltage in order to suppress power loss due to power transmission, and the high voltage electric power 40 is stepped down by the transformer equipment 42 installed in the electric room 41 or the like, It is supplied from the substation equipment 42 to each road light several hundred to several thousand meters away. Note that the electrical room 41 including the substation equipment 42 is usually installed under a road overpass or in an adjacent building. The voltage stepped down by the transformer 42 is generally a three-phase four-wire 460V (phase voltage 265V).

JP 2007-242258 A

  A road lamp with a built-in copper-iron ballast such as a high-pressure sodium lamp, a low-pressure sodium lamp, or a mercury lamp is supplied with the electric power of 460 V (phase voltage 265 V) stepped down by the substation equipment 42 as it is.

  On the other hand, road lights with built-in electronic circuits, such as Hf fluorescent lamps and LED road lights, are supplied with 415 V (phase voltage 240 V), which is further stepped down by a dedicated transformer 43 installed in an electric room 41 or the like. It was. The reason for this is that the semiconductor parts corresponding to the power supply of phase voltage 265V are very expensive, and it was very difficult both economically and in terms of space to incorporate a normal transformer for each road light. is there. As a result, an increase in distribution loss due to low-voltage distribution and an increase in transformer loss due to the substation equipment 43 dedicated to road lights with built-in electronic circuits cannot be avoided. Specifically, since the transmission loss is inversely proportional to the square of the transmission voltage, there is a large difference in transmission loss between the three-phase four-wire 460V transmission and the three-phase four-wire 415V transmission. In order to suppress this transmission loss, a thick transmission line with low resistance must be used, which is not preferable in terms of cost. Therefore, it is important to increase the transmission voltage as much as possible.

  The present invention has been made in view of the above circumstances, and the problem is that even if an electronic circuit is incorporated, it is possible to distribute the alternating current supplied from the transformation equipment as it is, and to reduce the distribution loss and the transformer loss. It is to provide a road light that can be suppressed.

In order to solve the above problems, a road lamp according to the present invention is:
A road light that illuminates a road with light emitted from a light emitting unit,
A self-winding transformer for stepping down a first AC voltage supplied from a transformer facility to a second AC voltage;
And a power supply unit having a conversion circuit for converting the AC second voltage into a predetermined current voltage form for supplying to the light emitting unit.

  The road lamp according to the present invention includes a power supply unit having a conversion circuit that converts an AC second voltage into a predetermined current voltage form for supplying the second light voltage to the light emitting unit. Since the road lamp according to the present invention has a built-in transformer, the AC first voltage supplied from the substation equipment can be stepped down to the AC second voltage. As a result, the AC first voltage supplied from the substation can be directly distributed to the road lamp, and when the voltage is stepped down to the second voltage by a dedicated transformer installed in the electrical room, etc., and then distributed to the road lamp. In comparison, distribution loss due to low voltage distribution can be suppressed. In addition, the dedicated transformer is usually a multi-winding transformer, and it is necessary to pass voltage and current through the primary winding and the secondary winding, respectively, which increases transformer loss. Since the current flowing in the primary side and the current flowing in the secondary side are canceled inside the transformer, the transformer loss can be reduced as compared with the compound winding transformer.

  In the road lamp of the present invention, the first voltage is preferably a phase voltage exceeding 240V.

  The AC first voltage supplied from the substation for road lights is generally a high voltage exceeding 240V in phase voltage, and generally includes an electronic circuit composed of electronic components in circulation. It is difficult for the road light to cope with the first voltage as it is. Since the road lamp of the present invention is stepped down from the first voltage to the second voltage by the autotransformer, it is not necessary to make the electronic circuit such as the conversion circuit correspond to the first voltage, and the cost can be reduced.

The figure which shows the external structure of a road light Functional block diagram showing an overview of road lights Conceptual diagram showing the configuration of a roadlight power supply system Conceptual diagram showing the configuration of a conventional road lamp power supply system The figure which shows the external appearance structure of another embodiment of a road light.

  A preferred embodiment of a road lamp according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an external configuration of a road light. FIG. 2 is a functional block diagram showing an outline of a road light. FIG. 3 is a conceptual diagram showing the configuration of the road lamp power feeding system.

  The road light 1 (or street light) can illuminate the road with visible light emitted from the light emitting unit 10 supported by the columnar body 1a. It does not specifically limit as a light source which comprises the light emission part 10, LED (light emitting diode), a fluorescent lamp, etc. are illustrated.

  As shown in FIG. 3, the road lamp 1 is supplied with power from a substation facility installed in an electrical room or the like located several hundred to several thousand meters away from the road lamp 1. The electric power supplied from the substation equipment is the AC power supply 2 having a three-phase four-wire 460V (phase voltage 265V).

  The road lamp 1 includes a self-winding transformer 11 and a power supply unit 12. The autotransformer 11 and the power supply unit 12 are built in the lower part of the main body 1a. An opening 1b as an inspection port is provided at the lower part of the main body 1a. The opening 1b is covered with a lid.

  The autotransformer 11 can step down the voltage (corresponding to the first voltage) of the AC power supply 2 supplied from the transformer equipment to a voltage lower than this (corresponding to the second voltage). The AC voltage supplied from the substation equipment to the road lights is generally a three-phase four-wire 460V (phase voltage 265V). In the present embodiment, the first voltage is 265 V in phase voltage, and this phase voltage is stepped down from 265 V to 240 V by the autotransformer 11. Since the current flowing in the primary side and the current flowing in the secondary side are canceled inside the transformer, the autotransformer 11 is smaller in size and loss than the rated capacity of a normal transformer.

  When the number of turns of the series winding is ns and the number of turns of the shunt winding is nc, the turn ratio a is expressed as nc / (ns + nc). Since the turn ratio a is close to 1, the self-winding transformer can be small in size and can reduce loss. In this embodiment, a = 240/265.

  The power supply unit 12 includes a conversion circuit 12a. The conversion circuit 12a has a function of converting the alternating current supplied from the autotransformer 11 into a predetermined current voltage form, and the current voltage output from the power supply unit 12 is suitable for lighting the light emitting unit 10. It can be.

  According to the road light of the present invention, even when an electronic circuit is built in, the alternating current supplied from the substation equipment can be distributed as it is, distribution loss and transformer loss can be suppressed, and energy saving can be achieved. It becomes possible. Further, it is not necessary to make the electronic circuit compatible with a high voltage, and the cost can be suppressed. In addition, when a road lamp with a built-in electronic circuit and a road lamp with a built-in copper ballast as in the present invention are mixed and installed on the road, the distribution line can be made common, thereby reducing the cost. be able to. Furthermore, since it is not necessary to install a dedicated transformer device in the electric room or the like, this also leads to a reduction in the size of the electric room or the like.

<Another embodiment>
The autotransformer 11 and the power supply unit 12 are not only provided inside the main body 1a of the road lamp 1 as in the above embodiment, but may be housed in a case external to the main body 1a. Further, as shown in FIG. 5, the road light 1 may be configured by accommodating a single-turn transformer 11 and a power supply unit 12 inside a light emitting unit 10. A road lamp 1 as shown in FIG. 5 is suitable for a lighting device in a tunnel or the like.

DESCRIPTION OF SYMBOLS 1 Road light 2 AC power supply 11 Self-winding transformer 12 Power supply part 12a Conversion circuit

Claims (2)

A road light that illuminates a road with light emitted from a light emitting unit,
A self-winding transformer for stepping down a first AC voltage supplied from a transformer facility to a second AC voltage;
And a power supply unit having a conversion circuit for converting the second AC voltage into a predetermined current-voltage form for supplying the second light voltage to the light-emitting unit. The road lamp according to claim 1, wherein the first voltage is a phase voltage exceeding 240V.

Images