JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Prerequisite

Generation and Measurement of high voltages

Course Objectives:

• To know different testing methods for high voltage apparatus.
• To know various standards for various kind of high voltage tests.
• To know the procedures to measure the partial discharges in high voltage apparatus.
• To know the causes for failure of insulators.

Course Outcomes

After Completion of this course, student will be able to

• Have knowledge on various types of high voltage testing on high voltage apparatus.
• Follow the various standards for best practice high voltage tests.
• Have basic ideas to avoid the failures occur in insulators.

UNIT - I

Non Destructive Testing Techniques : Measurement of DC Resistivity – Dielectric loss and dielectric constant of insulating materials – Schering bridge method – Transformer ration arm bridge for high voltage and high current applications – null detectors

UNIT - II

High Voltage Testing of Power Apparatus: Need for testing standards – Standards for porcelain / Glass insulator – Classification of porcelain / glass insulator tests - Tests for cap and pin porcelain/ Glass insulators. High voltage AC testing methods, power frequency tests - Over voltage tests on insulators, Isolators, Circuit Breakers and power cables.

UNIT - III

Artificial Contamination Tests: Contamination flashover phenomena – Contamination Severity - Artificial contamination tests - Laboratory Testing versus in-Service Performance – Case study. Impulse Testing: Impulse testing of transformers – Surge diverters – and other apparatus.

UNIT - IV

Partial Discharge Measurement : PD equivalent model - PD currents-PD currents PD measuring circuits – Straight and balanced detectors - Location and estimation of PD in power apparatus - PD measurement by non electrical methods - Calibration of PD detectors. RIV Measurements: Radio Interference – RIV - Measurement of RI and RIV in laboratories and in field Different test arrangements and their limitations.

UNIT - V

Insulators Fail: Handling – Vandalism – Quality control – Application problems Detecting defective Non Ceramic insulators. Making Insulators work in contaminated environments: Cleaning Modification of Insulator design – Mobile protective coatings-Solid water Repellent coating – line voltage reduction.

TEXT BOOKS:

• 1. High Voltage Engineering – by E. KUFFEL and W.S. ZAEGNL Pergamon press oxford 1984.
• 2. High Voltage Engineering- by M.S. Naidu and V. Kamaraju Tata McGraw Hill Publishing Company Limited New Delhi 2001

REFERENCES:

• 1. Discharge Detection in H.V. Equipment – by KREUGER F.H. Haywood Londor- 1964.
• 2. Outdoor Insulators- by Gorur & Cherney. M. Tech – I Year – II Sem. (PS H.V. Engg. / H.V. Engg.)