Medium Voltage
ABB – AIS UniGear ZS1 design features
UniGear ZS1 is medium voltage switchgear with a metal enclosure, suitable for indoor installations. Metal partitions segregate the compartments from each other and the live parts are air-insulated. Since the switchgear is highly modular type, this make simple selection of… Read more
Jun 06, 2011 | By Edvard Csanyi
Maintenance
Maintenance Of Meduim Voltage Circuit Breakers
Medium-voltage circuit breakers rated between 1 and 72 kV may be assembled into metal-enclosed switchgear line ups for indoor use, or may be individual components installed outdoors in a substation. Air-break circuit breakers replaced oil-filled units for indoor applications, but… Read more
Apr 17, 2011 | By Edvard Csanyi
High Voltage
MiCOM P139 – Feeder Management and Bay Control
MiCOM P139 is a cost-effective one-box solution for integrated numerical time-overcurrent protection and control. The unit’s protection functions provide selective short-circuit protection, ground fault protection and overload protection in medium- and high voltage systems. The systems can be operated as… Read more
Mar 30, 2011 | By Edvard Csanyi
Medium Voltage
PIX metal-clad switchgear – Schneider Electric
The PIX metal-clad switchboards are extensible on both sides and consist of modular functional units, linked by a busbar, and connected to the substation earth via an earthing bus. The cubicles are subdivided by metal partitions into four separate compartments,… Read more
Mar 21, 2011 | By Edvard Csanyi
High Voltage
Economics of GIS
The equipment cost of GIS is naturally higher than that of AIS due to the grounded metal enclosure, the provision of an LCC, and the high degree of factory assembly. A GIS is less expensive to install than an AIS…. Read more
Mar 04, 2011 | By Edvard Csanyi
High Voltage
SF6 gas as insulating and arc-quenching medium
Sulphur hexafluoride gas (SF6) is employed as insulation in all parts of the installation, and in the circuit-breaker also for arc-quenching. SF6 is an electronegative gas, its dielectric strength at atmospheric pressure is approximately three times that of air. It… Read more
Jan 06, 2011 | By Edvard Csanyi
Maintenance
Maintenance Of SF6 Gas Circuit Breakers
Sulfur Hexafluoride (SF6) is an excellent gaseous dielectric for high voltage power applications. It has been used extensively in high voltage circuit breakers and other switchgears employed by the power industry. Applications for SF6 include gas insulated transmission lines and’gas… Read more
Jan 04, 2011 | By Edvard Csanyi
High Voltage
Use Of Vacuum As A Breaking Medium
SF6 and vacuum are the two most modern breaking techniques in the fields of Medium Voltage (from 1 to 52 kV) and High Voltage (> 72.5 kV). They appeared in the 1960’s and rapidly developed as of the 1970’s. Today… Read more
Dec 22, 2010 | By Edvard Csanyi
High Voltage
Gas-Insulated Substations – GIS
A gas-insulated substation (GIS) uses a superior dielectric gas, SF6, at moderate pressure for phase-tophase and phase-to-ground insulation. The high voltage conductors, circuit breaker interrupters, switches, current transformers, and voltage transformers are in SF6 gas inside grounded metal enclosures. The… Read more
Nov 10, 2010 | By Edvard Csanyi
Medium Voltage
Aluminum vs. Copper: Conductors in Low Voltage Dry Type Transformers
In North America, aluminum is the predominant choice of winding material for low-voltage, dry-type transformers larger than 15 kilovolt-amperes(kVA). In most other areas of the world, copper is the predominant winding material. The primary reason for choosing aluminum windings is… Read more
Oct 27, 2010 | By Edvard Csanyi
Medium Voltage
Comparison Between Vacuum and SF6 Circuit Breaker
Until recently oil circuit breakers were used in large numbers for Medium voltage Distribution system in many medium voltage switchgears. There are number of disadvantages of using oil as quenching media in circuit breakers. Flammability and high maintenance cost are… Read more
Sep 05, 2010 | By Edvard Csanyi
