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
Medium Voltage
Four Crucial Switching Functions Of a MV Circuit Breaker (Facts You MUST Know)
The demands made on MV power systems, irrespective of the place of use of the circuit breakers, vary widely in nature. All these functions cannot obviously be performed with the same efficiency. Thus, finally any circuit breaker design can only… Read more
Oct 17, 2018 | By Edvard Csanyi
Energy and Power
Four important factors related to proper application of a LV circuit breaker
Consideration of all the factors related to proper application of a low-voltage circuit breaker goes beyond voltage, current, and interrupting rating. The performance of a specific type of circuit breaker may be influenced by nonelectrical factors related to the installation… Read more
Oct 15, 2018 | By Edvard Csanyi
Power Substation
The essentials of LV/MV/HV substation bus overcurrent and differential protection
The substation bus and switchgear are the parts of the power system used to direct the flow of power to various feeders and to isolate apparatus and circuits from the power system. These parts include the busbars, circuit breakers, fuses,… Read more
Oct 10, 2018 | By Edvard Csanyi
Medium Voltage
Standard tripping schemes and trip circuit supervision schemes for MV switchgear
Medium voltage switchgear is used for switching medium voltage loads through associated control, measuring, protective and regulating equipment. This operation also involves considerable manual intervention which therefore necessitates the fulfilment of safety requirements laid down in International Standards. A variety… Read more
Oct 08, 2018 | By Edvard Csanyi
Protection
Short circuit phenomenon you should properly understand
A short circuit in an electrical circuit is a part of the circuit that for some reasons has become “shorter” than it should be. The current in an electrical circuit flows the easiest way and if two points in a… Read more
Oct 03, 2018 | By Edvard Csanyi
Medium Voltage
Coordination analysis for a typical 13 kV distribution feeder of several lines
A typical 13 kV feeder of several lines at a distribution substation is shown in Figure 1. This is supplied from a 115 kV line through a 15/20/25 MVA transformer protected by a high-side fuse. Only one of the four… Read more
Oct 01, 2018 | By Edvard Csanyi
Power Substation
MV/LV transformer protection against temperature rise, overloads, short-circuit & overvoltages
When selecting the type of transformer correctly electrical engineer needs to know its different electrical and thermal properties and the resistance to stresses due to faults or normal service of the transformer itself. This is crucial to know. The transformer… Read more
Sep 26, 2018 | By Edvard Csanyi
High Voltage
Busbar protection schemes for distribution substations
Busbars play an important role in power transmission and distribution. They are employed as a central distribution point for all feeders. In the case of a fault, current on the busbar becomes high, resulting to mechanical destruction which would affect… Read more
Sep 24, 2018 | By Edvard Csanyi
Electric Motor
How to know if you set the correct current on a motor thermal overload relay
The full-load current at a given voltage indicated on the nameplate is normative for setting the overload relay. Because of the variable voltages around the world, motors for pumps are made to be used at both 50 Hz and 60… Read more
Sep 19, 2018 | By Edvard Csanyi
Monitoring
Secondary equipment you should always consider when retrofitting existing HV substation
This approach assumes retrofitting and upgrading old substation secondary equipment such as intelligent electronic devices (IEDs), monitoring sensors, power apparatus, communication protocol and operating standards to improve the overall performance or reduce cost without disrupting the continuity of service. For… Read more
Sep 17, 2018 | By Edvard Csanyi
Protection
Relay settings and applying high-impedance differential busbar protection scheme
Most of HV busbar faults involve single-phase and earth, but faults may arise from many different causes. The number of faults that stand out is between phases clear of earth. In fact, a large proportion of busbar faults result from… Read more
Sep 12, 2018 | By Edvard Csanyi
Electric Motor
Earth fault protection of an AC motor in four different earthing systems
One of the most common faults to occur on a motor is a stator winding fault. Whatever the initial form of the fault (phase phase, etc.) or the cause (cyclic overheating, etc.), the presence of the surrounding metallic frame and… Read more
Sep 10, 2018 | By Edvard Csanyi
