Investigation of residential customer safety-line, neutral and earth integrity

Reverse polarity and neutral failures can produce potentially dangerous voltage levels within electrical consumer's premises. While earthing at the consumers premises is normally good during the installation, it may degrade over time. Existing conventional electromechanical energy meters do not detect such conditions at the consumer premises. Hence, an accurate detection of conditions such as reverse polarity, earthing and neutral failure and degradation is essential for safe and reliable operation of a household electrical system. It is highly desirable that a protection system is designed such that it should detect such conditions accurately and it should not be oversensitive, as this could lead to an unnecessarily unacceptable high level of “nuisance” operation. In addition, such a solution should have to be reliable, economical and easily adoptable into existing premises without any major modification to the installation. This paper is intended to derive various necessary indices to detect neutral and earthing failure or degradation and reverse polarity conditions at the electrical consumer's premises. The simulation is carried out with the MATLAB¯ — SIMULINK¯ software with SimPowerSystems™ toolbox. These indices can be integrated into a smart meter or similar device to accurately detect earthing and neutral failure or degradation and reverse polarity conditions at consumer premises.