Fault Location Techniques for Distribution Systems

1. Paper 3.49 Fault Location Techniques forDistribution Systems R. Das, ABB USA M. M. Saha, ABB Sweden P. Verho, ABB Finland D. Novosel, ABB Switzerland

2. Fault Location in Electrical Network • Distance estimation methods • Long tradition in transmission level • Increasing need in distribution level • Problems in distribution network • Non-homogeneity of lines • Presence of laterals and taps • Earth faults in isolated and compensated networks • The paper reviews some methods for distribution network fault location

3. DMS Based Fault Location • Distribution Management System (DMS) • Application based on integration of SCADA and network data • Fault location is one application (in addition to e.g. restoration) • Finnish solution • Comparison of registered and calculated fault current • Excellent practical experience • Problem – Earth fault location • General model for control center application

4. Instructions for restoration operations Geographic view of faulted feeder Showing possible locations of fault

5. Advanced Impedance Based Fault Location Methods • Three methods reviewed (Novosel, Das, Saha) • Differentiating characteristics • load modeling method • simplified => limited requirement for feeder modeling • accurate => need for detailed feeder modeling • measurement requirements • from the faulty feeder • from incoming bay => only one locator needed • Based on simulation the accurate modeling reduces the error from ~10% to ~2%

6. Conclusions • Fault location in distribution network is a challenge • Methods vary depending on • Required measurements • Network modeling • Types of networks • In practical application there is both local (bay-level) and control center level application