Protection
The Essentials Of Voltage Transformers (Advanced Theory and Practice)
The most common voltage sources for power system measurements and protections are either wound transformers (voltage transformers) or capacitive divider devices (capacitor voltage transformers or bushing potential devices). Some new applications of resistor dividers and magneto-optic technologies are also becoming… Read more
Dec 19, 2018 | By Edvard Csanyi
Energy and Power
The essence of LV circuit breakers – Releases, tripping curves, characteristics and limitation
A circuit breaker is both a circuit-breaking device that can make, withstand and break currents whose intensity is at most equal to its rated current (In), and a protection device that can automatically break overcurrents which generally occur following faults… Read more
Dec 17, 2018 | By Edvard Csanyi
Power Substation
Protection scheme for remote private substation with small generator
Connections of private substations to utilities are made more complicated with the addition of private-owned generation facilities. The choice of relays and their placement must be made to ensure adequate protection of both the generator and the interface. The protection… Read more
Dec 12, 2018 | By Edvard Csanyi
Energy Generation
Protection Of The Power System Heart – The Generator
This technical article gives key points about the generator protection. To recover the generator from various kinds of faults, the generator protection scheme of the plant must be designed in such a way that groupings of protection are made respect to… Read more
Dec 05, 2018 | By Edvard Csanyi
Protection
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 units are illustrated in Figure… Read more
Nov 28, 2018 | By Edvard Csanyi
Energy and Power
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 units in the group where… Read more
Nov 26, 2018 | By Edvard Csanyi
Power Substation
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 related requirements are identified and… Read more
Nov 21, 2018 | By Edvard Csanyi
Electrical Lectures
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 transformer connections and operations as well as testing protection relays and systems. It’s also essential in understanding… Read more
Nov 19, 2018 | By Edvard Csanyi
Power Substation
Power transformer combined differential and restricted earth fault protection schemes
This technical article explains very important transformer protection methods and schemes: combined differential and REF, overfluxing, tank-earth and oil/gas protection. In previous article we described how overcurrent, restricted earth fault (REF) and differential protection of a transformer can be applied… Read more
Nov 14, 2018 | By Edvard Csanyi
Electrical Lectures
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 for a transformer protection vary… Read more
Nov 12, 2018 | By Edvard Csanyi
High Voltage
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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 are the key to development…...
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Nov 07, 2018 | By Ali Sepehri
Protection
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 is minimal. It is not… Read more
Nov 05, 2018 | By Edvard Csanyi
Protection
Eight most important distance relay characteristics (based on impedance comparison)
Some numerical relays measure the absolute fault impedance and then determine whether operation is required according to impedance boundaries defined on the R/X diagram. Traditional distance relays and numerical relays that emulate the impedance elements of traditional relays do not… Read more
Oct 31, 2018 | By Edvard Csanyi
Low Voltage
4 essential ground-fault protective schemes you should know about
While ground-fault protective schemes may be elaborately developed, depending on the ingenuity of the relaying engineer, nearly all schemes in common practice are based on one or more of the methods of ground-fault detection discussed in this article. Distribution circuits… Read more
Oct 29, 2018 | By Edvard Csanyi
Electrical Lectures
Biased-differential protection theory and application
The term biased-differential or percentage differential is based on the fact that the operating threshold increases with the through current. Because of that, comparison of upstream and downstream currents in the same phases is not convenient for transformer differential protection…. Read more
Oct 22, 2018 | By Edvard Csanyi
