Insulation fault location even more efficient and safe

IT systems 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 a failure of the entire system. On the contrary, IT systems can continue to be operated in a controlled manner and faults can be rectified at a later point in time without causing high downtime costs. 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, insulation fault location may require a high investment in terms of time and personnel.

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.

Bender's EDS440 insulation fault locator is adapted to the additional functionality of the new iso685 insulation monitoring device. The iso685-D-P variant is equipped with the locating current injector required for the insulation fault location. The operating menu for the setting of the EDS440 has been extended and adapted. Automatic bus scan to detect the connected EDS440 and customised text input for the alarm messages allow a comfortable 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 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-type or push-wire terminals. This enables fast installation and easy replacement of the devices.

The measurement is based on the technology of the previous EDS460 and the portable insulation fault locator EDS195PM, 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)
• Optimised cable auto-detection for the connected measuring current transformers
• Higher sensitivity in connection with the W ... AB series measuring current transformers

and thereby enables a more efficient insulation 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 W…AB series 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 injected locating current.

With the EDS440 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 and the considerably reduced maintenance effort lead to increased safety and also to higher business efficiency of technical installations of any type.

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 indicated more localised and more 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-D-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."