Introduction
In order to achieve more efficient voltage regulation in a power system, coordinated secondary voltage control has been proposed, bringing in the extra benefit of enhancement of power system voltage stability margin.

The study is presented by the e.g. with two SVCs and two STATCOMs in order to eliminate voltage violation in systems contingencies. In the paper, it is proposed that the secondary voltage control is implemented by a learning fuzzy logic controller.

A key parameter of the controller is trained by P-type learning algorithm via offline simulation with the assistance of injection of artificial loads in controllerâ„¢s adjacent locations. A multiagent collaboration protocol, which is graphically represented as a finite state machine, is proposed in the paper for the coordination among multiple SVCs and STATCOMs.

As an agent, each SVC or STATCOM can provide multilocation coverage to eliminate voltage violation at its adjacent nodes in the power system. Agents can provide collaborative support to each other which is coordinated according to the proposed collaboration protocol.

The major contributions of the paper are:

o A multiagent collaboration protocol for the multiple FACTS voltage controller is proposed.
o Multilocation coverage of power system voltage profile around a voltage control agent is suggested
o A novel scheme to design a learning fuzzy logic secondary voltage controller.