Validating correct insulation monitoring with exclusion management

To have proper insulation monitoring of the electrical power system, it is important that it is monitored by one insulation monitoring device at a time.

For most of the systems that do not include multiple incomers or coupling of multiple busbars, this is easily achieved because there is only one device in the system permanently active.

For systems with multiple incomers or power busbar coupling, the monitoring system embeds several devices (SeeInjection inhibition input (Inhibit. Input)). The exclusion/activation of each device according to the electrical power system configuration is managed through the injection inhibit contact. It is important at commissioning to validate that insulation of every part of the electrical power system is monitored by an active device and that the management of exclusion/activation of each device does not lead to a part of the power system monitored by more than one device or no device. This is to avoid insulation fault not being reported.

Insulation metering and insulation fault detection testing

To verify the device is correctly installed and configured:

  • Check the installation by connecting a known impedance between wiring terminals 1 and 3 of the device (10 kΩ) and verifying that the impedance is correctly measured. For this test, do not connect the device to the monitored network.

  • Check the insulation fault detection by strapping wiring terminals 1 and 3 of the device (creating a 0 Ω insulation fault). For this test, do not connect the device to the monitored network.

Insulation alarm relay wiring testing

To verify the insulation alarm relay is correctly wired in the installation, perform a device test with the relay.

Disconnected injection detection

By default, the disconnected injection detection parameter is set to OFF. This setting avoids the Disconnected Injection Detected message to display when installing and commissioning the device before connecting it to the power system and load.

According to the system or application requirements, you can enable the disconnected injection detection parameter (setting it to ON) when executing the final commissioning. Thus the device can continuously perform this check during operation and report any injection connection or wiring issue.

HV1/HV2 wiring testing

The connection between the device and the voltage adaptors IM400-1700, PHT1000, or P1N is key for a correct behavior of device.

Check the wiring of HV1 and HV2 wiring terminals to the voltage adaptor. Connect a known impedance (for example, 10 kΩ) between IM400-1700 wiring terminal 1 and the device wiring terminal 3, or between PHT1000 wiring terminal 3 and device wiring terminal 3, or between P1N wiring terminal 2 and device wiring terminal 3. Check that the device correctly measures the impedance. For this test, do not connect IM400-1700, PHT1000, or P1N to the monitored power system.

Protection password setting

To avoid any unintended operation by not authorized or untrained personnel, set the protection password.

QR Code is a registered trademark of DENSO WAVE INCORPORATED in Japan and other countries.

Was this helpful?