Major causes of aging in composite insulators Most technical work concentrates on the aging of nonceramic insulators and the development of test methods that simulate the aging process. Transmission lines operate in a polluted atmosphere. Inevitably, insulators will become polluted after several months in operation. Fog and dew cause wetting and produce uneven voltage distribution, …
General principles of electricity supply systems
Transmission of electricity The generation of electricity in most modern power stations is at 25 kV, and this voltage is then transformed to 400 kV for transmission. Virtually all the generators of electricity throughout the world are three-phase synchronous generators. The generator consists of a prime mover and a magnetic field excitor. The magnetic field …
Special Transformers for Industrial Applications
Specific Industrial Transformers A number of industry applications require specific industrial transformers due to the usage of power (current) as a major resource for production. Electric arc furnace transformers (EAF) DC electric arc furnace transformers (DC EAF) Rectifier transformers Converter transformers Line Feeder Electric arc furnaces (EAF), ladle furnaces (LF) and high-current rectifiers need a …
Talking About HV Shunt Reactor Switching (part 2)
Continued from first part: Talking About HV Shunt Reactor Switching (part 1) Content Scope (explained in previous part) Shunt reactors application (explained in previous part) Closing operation (explained in previous part) Opening operation Conclusions Opening operation In the case of shunt reactors the current to be interrupted are very low (typically less than few hundreds …
Talking About HV Shunt Reactor Switching (part 1)
Content Scope Shunt reactors application Closing operation Opening operation (in next part) Conclusions (in next part) Scope These notes aim to give basic idea of the main criticalities related to HV shunt reactor switching, particularly in terms of voltage, and how such problems are faced and solved by modern switching technology. Go to Content ↑ Shunt reactors …
Commissioning of HV Panel – Operational and Functional Checkup
Main Objective The main objective of the test is to check the proper operation function of the circuit breaker; in this test we do the following: A. Close Operation Test – Local—Remote This test is conducted by manual, Local and Remote. For the manual Operation test, we will charge the spring manual and breaker is …
High voltage testing – Direct current (DC)
DC Tests DC tests are used mainly to do “pressure tests” on high voltage cables. Although the cables operate with AC, AC testing is not practical. The high capacitance of the cables necessitates AC test sets with a high kVA rating to be able to supply the capacitive current. In the case of DC, once the …
Erection procedure for HV switchgear (Part 2)
Continued from first part: Erection procedure for HV switchgear (Part 1) Positioning of cubicles Positioning of the cubicles should start near to the centre of the switchboard, installing as early as possible the enclosures associated with any special chambers or trunking. The first enclosure should be positioned and checked to ensure the side sheets are …
Erection procedure for HV switchgear (Part 1)
Important points Before commencing erection of HV switchgear check that all connections are tight on busbars and on main circuits as well as auxiliary circuits. Examine the insulation very carefully, because there have been reported cases of burned out connections due to failure to observe this precaution. Obvious faults such as distorted panel work, broken …
Conductor Types Used For Overhead Lines
Aluminium and its alloys conductor steel reinforced The international standards covering most conductor types for overhead lines are IEC 61089 (which supersedes IEC 207, 208, 209 and 210) and EN 50182 and 50183 (see Table 1). For 36 kV transmission and above both aluminium conductor steel reinforced (ACSR) and all aluminium alloy conductor (AAAC) may …
