WO1998045910A1

WO1998045910A1 - Auxiliary power device for switchgear

Info

Publication number: WO1998045910A1
Application number: PCT/SE1998/000594
Authority: WO
Inventors: Lennart BALGÅRD; Micael Lindqvist; Håkan FRÖBERG
Original assignee: Abb Ab
Priority date: 1997-04-07
Filing date: 1998-03-31
Publication date: 1998-10-15
Also published as: SE9701270L; SE510302C2; SE9701270D0

Abstract

n auxiliary power device (1) for intermediate voltage switchgear includes a space (3) for receiving a set of batteries (4) and monitoring and charging circuitry therefore as well as cable connecting means. The auxiliary power device is constructed as a mobile rollable unit (1) having a panel portion (2) and a portion (3) for receiving batteries (4) or condensators, said unit being adapted to be inserted into a space at the lower part of a module (12) of a switchgear (10). The unit comprises connecting means for the connection to connecting means in the connecting module. The invention also concerns a modular switchgear including an auxiliary power device.

Description

AUXILIARY POWER DEVICE FOR SWITCHGEAR

This invention concerns an auxiliary power device for switch- gear in accordance with the preamble of claim 1.

Auxiliary power devices for switchgear aim to ensure substitute power for manoeuvring essential functions of the switchgear such as operation of release coils and control systems in case of default and disturbances of different kinds. From this it is understood that the auxiliary power function is of essential importance for the safety of the switchgear.

Previous auxiliary power devices have been placed at a distance from the switchgear itself and have typically been located in separate battery rooms or cabinets with batteries placed on shelves and monitoring and control equipment arranged inside the room or the cabinet and some times with panels, displays and the like on a cabinet door.

The reason for the location at the distance from the switchgear has often been that the auxiliary ^' power device has been regarded as a separate aggregate, which therefore has been located separately from the switchgear. In certain cases existing auxiliary power devices have been connected when switch- gears have been installed. This has resulted in drawing of cables at the site having been particular for each installation which essentially has increased the time for the installation to be operational. The lengths of the cables have also resulted in demands for relatively thick and thereby expensive cables in order to reduce the voltage drop in the cables as much as possible.

The invention aims to eliminate the drawbacks of the prior art. This aim is obtained in an auxiliary power device as above by the features of the characterizing portion of claim 1.

By the invention the auxiliary power device is integrated into the switchgear which results in essential advantages, since hereby the installation time for the switchgear as a hole is considerably reduced. The problem of voltage drop in feed cables are mainly eliminated resulting in reduced cable consumption and possibility of using thinner cables. Further, the grounding of the switchgear may be utilized, eliminating the need of separate grounding for the auxiliary power device.

Further, the safety of the plant is increased since the auxiliary power system is protected in the switchgear itself. The risk of breakage of feed and communication cables is thus eliminated. Finally, possibilities of radically simplified connections are achieved since drawing of cables and connections which are specific for the particular application will be unnecessary. The invention also allows simple maintenance of the unit comprising the entire auxiliary power device and also replacement (even in operation) , which further accentuate the importance of the invention.

Even if the invention here is mainly described at the back- ground of the use of batteries, it is not excluded that the auxiliary power device instead utilizes condensators as an auxiliary power source.

The invention also concerns an intermediate voltage switchgear with modular construction, whereby the switchgear includes a particular connecting module whereby one of the modules provides a space at its lower portion for receiving a unit comprising an auxiliary power device. By the feature of claim 6, the simplicity is emphasized since no separate charging feed is necessary.

Further advantages are obtained by the features of the other claims and are clear from the following detailed description of an embodiment which is illustrated to the background of the annexed drawing, wherein:

Fig. 1 in a perspective view diagramatically shows an auxiliary power device according to the invention, and

Fig. 2 and 3 show the auxiliary power device according to Fig. 1 incorporated into the connecting module of an intermediate voltage switchgear.

In Fig. 1 1 indicates an auxiliary power device which is constructed as an unit and is intended to be integrated into a modular switchgear and which ensures substitute power for the operation of release coils, micro computers etc., which are present in the intermediate voltage modules of the switchgear. The unit 1 is constructed as a trolley having rollers 5 for rolling on the floor of a switchgear room, on carrier profiles etc. The unit 1 includes a panel portion 2 which is arranged as an upstanding, relatively flat portion on one side of the unit 1. The unit further comprises a horizontal space for receiving, side by side, batteries 4 in a battery portion 3, resulting in a low placement of batteries. On the front side of the panel portion 2, there is a display with the usual indicating instruments and fuses. Connecting means are arranged on the back side of the panel portion for connecting the auxiliary power device to the connecting module of the switchgear.

Fig. 3 diagrammatically shows a front view of a switchgear 10 including intermediate voltage modules 11 and a connecting module 1 inside which all external connection means for the switchgear are integrated. At least one of the intermediate voltage modules, however, comprises coupling means for incoming current leads to the switchgear. As can be seen from Fig. 3, the panel portion of the auxiliary power device 1 is an integral part of the front of the 'switchgear when it is inserted and in operation.

The modular construction of the switchgear results in consider- able advantages with respect to the possibility of reducing the installation times and costs in connection therewith. This is mainly achieved by connections and functions being depending of the specific application and/or the demands of the customer being integrated in the connecting module and in software which is stored in the control system of each switchgear unit

(present in a separate intermediate voltage module) . All other parts of the switchgear are thus standardised to a high degree. Said advantages are emphasised by integrating an auxiliary power device according to this invention into the switchgear. One advantage of integrating the auxiliary power into the switchgear is that it is possible to deliver a "turn key" switchgear, which as a whole may be tested at the production plant and delivered by a contractor.

The location is also shown in Fig. 3 which diagrammatically shows the principle of inserting the auxiliary power unit 1 into a connecting module 12. This Figure which is a diagrammatic side view, shows that the front surface of the panel portion is essentially in the same plane as the front surface of the connecting module.

A low placement of the batteries makes it possible to utilise the lower temperature at the lower part of the switchgear room in order to keep the batteries at a relatively low temperature, which is a further advantages of the invention, since it results in prolonged working life of the batteries.

Another advantages to be achieved by the invention, is that it in a concrete manner makes it possible to change to standardised auxiliary voltage, for example 48V or 110V, as a contrast to the situation hitherto ruling with a long row of different auxiliary voltages according to needs, desires and the customers possessions of apparatuses. This change results in the possibility of radically reducing the number of component varieties as well as the makings of documentation for the specific clients.

Claims

C L A I M S

1. Auxiliary power device (1) for intermediate voltage switch- gear including a space (3) for receiving a set of batteries (4) and monitoring and charging circuitry therefore as well as lead coupling means, c h a r a c t e r i z e d in that the auxiliary power device is constructed as a mobile rollable unit (1) having a panel portion (2) and a portion (3) for receiving batteries (4) or condensators, said unit being adapted to be inserted into a space below a module (12) of a switchgear (10) which is constructed with intermediate voltage modules and a connecting module for external cables, and that the unit comprises connecting means for the connection to connecting means in the connecting module.

2. Device according to claim 1, c h a r a c t e r i z e d in that the front side of the panel portion (2) of the unit (1) will be essentially in the same plane as the front side of the connecting module in the inserted position of the unit.

3. Device according to claim 1 or 2, c h a r a c t e r i z e d in that it comprises means for grounding connection to a grounding rail, which is present inside the switchgear.

4. Device according to any of the claims 1 - 3, c h a r a c t e r i z e d in that it provides standardised auxiliary voltage.

5. Intermediate voltage switchgear having modular construction, whereby it includes at least two intermediate voltage modules

(10) and a connecting module (12), whereby one of the modules comprises a lower space for receiving an auxiliary power device

(1) according to any of the claims 1 - 4.

6. Switchgear according to claim 5, c h a r a c t e r i z e d in that the feed current for charging the auxiliary power device is arranged to be drawn over a voltage transformer from the primary current lead which conducts the intermediate voltage.