More developments in automation of cathodic protection

IN MANY cathodic protection installations, the use of automatic control of current is based on the premise of master and slave equipment. In this case, if the system is applied to a generating station cooling system, the water system is considered in convenient units (e.g. one turbo alternator unit). The most important item in the cooling system associated with the turbo alternator is then selected as the master unit, the usual choice being the main steam condenser. In this master unit are installed the sensing electrodes which will form the basis of the feedback circuit which directs the operation of the rectifier. The less important items of equipment in the cooling circuits are then fed from the distribution busbars via suitable trimming resistances. A typical installation is shown in Fig. 1. Although the supply to the minor items will be appropriately affected by changes in electrolyte, it is clear that as far as these minor items are concerned the mode of control cannot be regarded as automatic.