Vigilohm, permanent insulation monitor
Renewal of the Vigilohm range of insulation monitors for IT earthing systems, through to UL Functional Safety certification.
- Client
- Schneider Electric
- Period
- 2010 - 2014
- Role
- Numerical simulation, algorithms and real-time embedded software
The need
In an IT earthing system, the neutral is not connected to earth. A first insulation fault does not trip the installation, which keeps it running, but a second fault makes it dangerous. The Vigilohm monitor continuously measures the insulation resistance of the network to earth, and its capacitance on some models, to report the first fault in time. The measurement is indirect: everything rests on signal processing and on demonstrating that the measurement chain is correct.
The solution
- 01
Numerical simulation of the measurement principle, and tuning of the algorithms in MATLAB and Simulink.
- 02
Embedded software development in C++ on a real-time system, with parts in C and assembly, on STM32.
- 03
ADC drivers, Modbus functions, processor and memory self-tests, assembly tester.
- 04
UL Functional Safety certification, carried out with the certification body.
- 05
Patent filed on the calibration of a component in the measurement chain.
The outcome
Range certified UL Functional Safety and sold by Schneider Electric, with a patent filed on the calibration method.
In pictures
