Abstract: Transformers are in a parallel circuit in which a tap changer with a control sensor is associated with each of the transformers and all control sensors are connected together by a communications connection. Each control sensor generates a measurement that is transferred by the communications connection. A measurement is generated with each of the control sensors, and at least one of the measurements of the control sensors of the transformers by the communications connection is transferred to N?1 control sensors. Then a controlling deviation caused by a circuit reactive current is calculated for each control sensor on the basis of the measurements of the control sensors. Finally the tap changer associated with each transformer is actuated by the respective control sensor as a function of the calculated controlling deviation such that minimization of the circuit reactive current is carried out for the respective transformer.

Abstract: A method for controlling the parallel running of a plurality of transformers T1, T2, . . . , TN) in a parallel circuit (10) is disclosed, wherein each of the transformers (T1, T2, . . . , TN) is assigned a measuring/control device (12) and all the measuring/control devices (12) are connected to one another via a communication connection (16). In the absence of a standby signal of at least one measuring/control device (12), interruption (16) of the communication (14) is displayed. The measured values determined at the time (t) of the interruption remain constant for the duration of the interruption (16) and are also included in the calculation of the control errors during the interruption (16), in order to minimise a circuit reactive current of the transformers (T1, T2, . . . , TN).

Abstract: A method for producing biogas from biomass in a biogas reactor, wherein at least one standard value is provided for the concentration of at least one trace element in a biogas reactor for efficient biogas production, biogas is produced from biomass in the biogas reactor, the concentration of at least one trace element in the biomass is determined in the biogas reactor, and in the event that the determined trace element concentration falls below the standard value, deficient trace elements are added to the biogas reactor.