Guest Editorial: Special Section on the Fourth IEEE International Workshop on Applied Measurements for Power Systems (AMPS 2013) Aachen, Germany, September 25–27, 2013

The fourth IEEE International Workshop on Applied Measurements for Power Systems (AMPS 2013), promoted by TC-39 of the Instrumentation and Measurement Society (Measurements in Power Systems), was hosted, like the first three editions, by E.ON Energy Research Center RWTH, Aachen University, Germany, on September 25–27, 2013. The six papers in this special section are extended versions of papers presented and discussed during the workshop.