The modern outdoordisconnectors SA 24 (load disconnectors 24 kV) with ground knives or without such are for 20 kV current transformer lines and electric device commutation in the open air. We can produce disconnectors with fixed ground knifes at the outgoing line (moving insulator) side. They have excellent resistance and in the process of the device design the special attention was put to the Latvia climate peculiarities. The picture shows the process of the disconnector work tests in winter with 10 mm ice layer. The disconnectors can be installed on one foot and portal type wooden poles, or metal poles of special construction. It is possible to produce other disconnector variants and other means of fixing. For example disconnectors can have electric bow extinguishers chambers for the current up to 400A (during active load). Outdoor disconnectors can be modified and add switching on/off from distance – remote control (radio or GSM). If you are not on the object you can send message to the disconnector or give command with help of radio waves and it will switch on load with motor drive. SA 24 outdoor load disconnectors are designed in such a way that they occupy minimum space during transportation and are easy to install. Technical characteristics Rated voltage, kV | 20 | Maximum rated voltage, kV | 24 | Frequency, Hz | 50 | Rated current, A | 200* | Heat resistance current, (1 sec.), kA | 12,5 | Tripping load current:
mainly active load, A (100 tripping cycle)
reactive load, A (20 tripping cycle) |
25
15
| Allowable tripping of mechanical strength, n | 2000 | Outdoor temperature °C | -60 … +40 |
* On customer demand JAUDA produce outdoor disconnectors with rated current up to 400 A.
Outdoor disconnectors to conform to IEC 129-84 and ГОСТ 689-90 standards. Construction The disconnector construction is of folding type and consists of a number of poles, hand drive and assembly set. Three pole disconnectors are assembled by assembly of separate poles on common traverse and connecting main pole and ground knifes by square pipes. Switching off low load currents, elimination of electric bow takes place between fixed to the moving insulator spring hook and flexible contact – spring attached to the fixed insulator. The disconnectors are equipped with blocking devices, that do no allow to connect ground knives to switched on main knives and connect main knives to the switched on ground knives. Disconnectors with hand drive have special points for connection of earthing wire. Delivery sets The sets delivered to the customers contain disconnector poles, hand drives, assembly kit and technical documentation. The assembly kit has parts for line wire attachment to the traverse, but not insulators, which have to be ordered separately. Maintenance Disconnector poles and their rotating parts do not need special maintenance. Though it is advisable to check disconnector contacts and fixtures together with transformer and line check ups. To register disconnector switching on/off cycle at low voltage currents (see technical characteristics). Allowed ice coat – 10 mm.
The average useful life till replacement – 30 years. A/S EF "JAUDA" offers full range of outdoor disconnectors for medium voltage networks. | 
