IT systems on board have the great advantage that, as described in DIN VDE 0100-410 and in section 411 of IEC 60364-4-41, a first fault does not lead to an automatic shutdown of the power supply and thereby to system downtime. On the contrary, IT systems can continue to be operated and controlled, and the fault can be rectified later when it is more convenient to do so without having high downtime costs and dangerous situations at sea or in the harbour. The basis for this are insulation monitoring systems. They monitor the insulation resistance and signal when the value falls below a specific threshold value. With this information, the appropriate time for the insulation fault location can be determined. In the case of complex systems and power supplies that are distributed over a large area on board, the insulation fault location may require a high investment in terms of time and personnel. Especially in automation and control circuits, switching off at sea is not possible and fault location is very difficult. Here, insulation faults can influence measured values and, for example, lead to incorrect tank level displays or even false tripping of temperature or pressure sensors.

The solution to this problem are insulation fault location systems that comply with the product standard DIN EN 61557-9 (IEC 61557-9). These search automatically for insulation faults during operation and indicate the faulty outgoing circuit.

The Bender insulation fault locators EDS440/441 are adapted to the additional functionality of the new insulation monitoring device iso685. The iso685-S-P variant is equipped with the locating current injector required for the insulation fault location. The operating menu for the setting of the EDS440/EDS441 has been extended and adapted. An automatic bus scan to detect the connected EDS440/EDS441 and customised text input for the alarm messages allow a convenient application by the operating personnel.

There always seems to be a space problem in control cabinets, in which insulation fault locators of the type EDS are usually installed. Here, the benefit of the EDS440/441 is its smaller enclosure width. It is also more compact in depth.

The type of connection is realised by plug-in terminals, which are optionally available as screw or push-wire terminals. This enables fast installation and easy replacement of the devices.

The measurement is based on the technology of the EDS460/461 and the EDS195P, but was optimised according to the following criteria
 

• Higher accuracy
• Reduced interference effects from the system to be monitored
• Residual current measurement with adjustable response values (RCM function) for preventive fire protection
• Optimised cable auto-detection for the connected measuring current transformers
• Higher sensitivity in connection with the series W … AB measuring current transformers

It thereby enables a more efficient fault location.

The device series consists of five variants:
 

• EDS440-S and EDS440-L for use in main circuits with a response value for the generated locating current of 2…10 mA
• EDS441-S and EDS441-L for use in control circuits with a response value for the generated locating current of 0.2…1 mA.
• EDS441-LAB in combination with series W…AB measuring current transformers for use in control circuits with very high leakage capacitance values and at the same time with the requirement of a maximum locating current of e.g. < 1.8 mA. A response value of 0.2…1 mA is required for the generated locating current.

With the EDS44x device series the user is offered a system with outstanding value for money. Simple installation and operation have been combined with the latest efficient technology for automated insulation fault location. The significantly improved availability of the installed power supply as well as the automation system and the considerably reduced maintenance effort lead to increased safety and to higher business efficiency on board.

INFO BOX

Automatic insulation fault location during operation and indication of the faulty outgoing circuit offer the system operator the following advantages:
 

• A shutdown of the system (or system parts) is not necessary.
• No live work is required for the fault location. Hazards for electrically skilled persons are thereby avoided.
• The insulation fault location is done automatically during operation.
• The fault location is narrowed down and indicated precisely.
• The information on the faulty circuit is available within seconds.
• Alarm messages can be displayed, and parameters can be entered via a web browser of the iso685-S-P.
• The recommendation mentioned in the basic safety standard DIN VDE 0100-410 (IEC 60364-4-41) is fulfilled:

"It is recommended that a first fault be eliminated with the shortest practicable delay."