Insulation monitoring device

An isolation monitor (also insulation monitoring device ) monitored in power systems the insulation condition of an IT network, so low-voltage networks without operational earthed star point on the falls below a minimum insulation resistance. In general, a current measurement to earth is to performed. If an error occurs, upon exceeding the insulation fault current that can either be carried out only a warning issued or a shutdown of the relevant network outgoing circuit.

History

The first insulation monitor was developed by Walther Hans Bender in Frankfurt / Oder and under the name of A- isometer logged into the Reich Patent Office in 1939 for a patent ( Patent 722 348 ). These were the first active measuring insulation monitoring and Erdschlussanzeigeeinrichtung for three-phase systems in the lignite mining. The technical term isometer was born on July 31, 1952 at the German Patent and Trademark Office under registration no. 622564 entered.

Application

Be applied insulation monitor where power supplies and their disposals must be failsafe, ie where a simple mistake ( single earth fault ) may not lead to a loss of power or and of the waste stream in question, such as in operating rooms and intensive care units, in railway signal boxes in critical areas in the industry, in conventional power plants and photovoltaic systems on ships or in electric vehicles.

The first ground fault is in IT systems in principle not dangerous as long as the discharge capacity of the plant is small enough, which usually is the case with smaller spatial extent of the network. He must be reported by the insulation monitor so that it can be corrected in a timely manner. If a first earth fault is not resolved, is at a second error is the risk that the wetted closes a circuit on both flaws. For this reason, the localization and removal of insulation faults by DIN VDE 0100-410 (VDE 0100 Part 410): 2007-06 mandatory. Since the debugging of the system often poses a challenge, fixed and mobile devices to locate ground faults are used (English Earthfault detection system, EDS).

Related methods with similar goals, which is used in the high voltage range as the high voltage systems, the resonant-ground.