All our Electrode boilers are constructed with a high resistance neutral point. This means that the active water and electrode system are contained in a vessel supported inside the boiler on insulators, and acting as the neutral point of the three phase system.
The diagram above illustrates the way the electrical equipment for a high voltage boiler is built up in principle. The installation usually comes in two steel cabinets, one for the high voltage unit and the other with the instruments and controllers; this includes a SCADA unit which can be networked to the client’s operating control rooms.
The high voltage equipment can be installed in the boiler room, at some distant location or as an integral part of the cellular arrangement in a transformer room.
The control cabinet stands close to the boiler, however, to facilitate full supervision over all instruments during such operations as start-up.
Large boilers must be fitted with two three-electrode sets, which can either have separate circuit breakers or be linked together with a single breaker.
The current in each electrode is monitored in order to keep electrode wear under observation.
There are no differences between electric and oil-fired boilers with regard to requirements for materials, performance and so forth, or for operating personnel.
Virtually all boilers today come equipped for unmanned operation over a period of up to 16 or more hours, which calls for a certain amount of extra automation and safety equipment. The latter is inspected and tested for functional performance on a routine basis.