PARALLEL RUNNING

The rotors of alternators are equipped with damping winding as standard for parallel operation and unbalanced loads, having this characteristic allows to run in parallel with other alternators and also with the mains.

For a satisfactory parallel operation, it is important to achieve an even distribution of the effective and reactive load.

For the distribution of reactive load, the revolution drop graphics should be equal for revolution regulators of motors which activate the alternators. The mount of reactive load distribution is dependent on alternator's excitation. For two alternators in parallel operation, exciters regulators should have lowering characteristic and voltage drop should be as equal as possible.

For a better distribution of the effective load, in the secondary current transformer which is mounted to V phase of the alternator, the inducted voltage is added vectorially to voltage voltage regulator's reference voltage by a load resistance. This added voltage becomes more effective as the alternator' load current Cos phi is unsteady.