Connection schematics of voltage transformers for protective applications
Voltage transformers would have primaries that are either connected directly to the power system (VTs) or across a section of a capacitor string connected between phase and ground (coupling capacitor voltage transformers – CCVTs). Typical… Read more
Nov 28, 2018 | Edvard
10 unbalance detection schemes for removing failed capacitor bank from the system
The main purpose of an unbalance detection scheme is to remove a capacitor bank from the system in the event of a failure and fuse operation. This will prevent damaging overvoltages across the remaining capacitor… Read more
Nov 26, 2018 | Edvard
Main components of a Gas Insulated Substation (GIS) you should know about
Gas-insulated substations (GIS) use circuit breakers, disconnect switches, and grounding switches, and have various means of indicating their position, either opened or closed, so the same as in air-insulated substation (AIS). Operation of a GIS…...
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Nov 23, 2018 | Edvard
Coordinating study in protection of utility supply line, transformer and plant main bus/feeder
The installation of a dedicated substation to serve a plant actually involves an interface between the utility and the plant. Close coordination between utility and plant personnel is essential so that relaying, control and other… Read more
Nov 21, 2018 | Edvard
What is polarity and why it’s important for transformers and protection relays
Polarity is very important for the operation of transformers and protection equipment. A clear understanding of polarity is useful in understanding and analyzing of transformer connections and operation as well as testing of protection relays… Read more
Nov 19, 2018 | Edvard
Power transformer protection relaying (combined differential & restricted earth fault)
In previous article we described how overcurrent, restricted earth fault (REF) and differential protection of a transformer can be applied and explained their schemes. This part continues with other, also very important protection methods and… Read more
Nov 14, 2018 | Edvard
Power transformer protection relaying (overcurrent, restricted earth fault & differential)
The problems relating to transformer temperature rise above an assumed maximum ambient temperature require some means of protection. Let’s summarize the problems and the possible forms of transformer protection that may be used. The considerations… Read more
Nov 12, 2018 | Edvard
Neutral earthing systems of generator sets (gensets)
Generator sets have specific features that must be taken into account for protection against electric shocks. Mobile sets cannot be connected to earth and their connection by means of a flexible cable can be easily… Read more
Nov 08, 2018 | Edvard
The raising technology of high voltage vacuum circuit breakers (that could replace SF6…)
Because of great harmfulness of greenhouse effect, SF6 gas has to be limited. It is necessary to develop high voltage vacuum circuit breaker to replace SF6 circuit breaker. Insulating structure and arc-characteristics of vacuum interrupter…...
PREMIUM Membership Required
This technical article/guide requires a Premium Membership. Get access to all premium HV/MV/LV technical articles, electrical engineering guides, and papers. Check out each plan's benefits and choose the membership plan that works best for you or your organization.You can choose an annually based Plus, Pro, or Enterprise membership plan.Log InSign Up
Nov 07, 2018 | Ali Sepehri
Ground faults in ungrounded systems (risks & detection)
Ungrounded systems are power systems with no intentionally applied grounding. However, they are grounded by the natural capacitance of the system to ground. Thus, the fault current level is very low, such that equipment damage… Read more
Nov 05, 2018 | Edvard
