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… Read more
Nov 14, 2018 | By Edvard Csanyi
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… Read more
Nov 12, 2018 | By Edvard Csanyi
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… Read more
Oct 22, 2018 | By Edvard Csanyi
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… Read more
Oct 03, 2018 | By Edvard Csanyi
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… Read more
Sep 26, 2018 | By Edvard Csanyi
Applying CTs in protection schemes for transformers, generators, machines etc.
Various types of instrument transformers are currently in use on the basis of the varied applications of these devices. The construction aspects and sizing play an important role in the… Read more
Sep 05, 2018 | By Edvard Csanyi
Current and voltage digital transformation in a modern substation protection and automation
Developments in communication have done much to realize the digital substation, but to realize a full digital substation it is necessary to have everything in digital form. Whilst much substation…...
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Jul 25, 2018 | By Edvard Csanyi
Four ways to bolster the short-circuit withstand capability of HV transformers
There are many methods applied to bolster the short circuit withstand capability of the transformers: improvement of the materials, reforming of the design and good maintenance in the operation process… Read more
Jun 13, 2018 | By Edvard Csanyi
The essential physics behind transformer differential protection (You MUST know)
Transformers are important system components available in many different constructions. The range of HV transformers reaches from small distribution transformers (from 100 kVA) up to large transformers having several hundred… Read more
May 14, 2018 | By Edvard Csanyi
Three Common Transformer Phenomena That Should Worry Substation Engineers
Even with the best engineering practices, abnormal situations can arise that may produce damage to power transformer and other equipment and compromise the continuity of the delivery of quality power… Read more
May 02, 2018 | By Edvard Csanyi
Where and Why Do We Use Phase-Shifting Transformers?
Because of the predominantly inductive character of the power system, an active power flow between source and load must be accomplished with a phase lag between the terminals. Phase-shifting transformers… Read more
Apr 23, 2018 | By Edvard Csanyi
Losses in the power transmission system and short, medium and long line model analysis
Like all other power system systems, no matter how carefully the system is designed, losses are present and must be modeled before an accurate representation of the system response can… Read more
Feb 21, 2018 | By Edvard Csanyi
AC Auxiliary Systems In Power Substations (Design Requirements and Equipment)
Substation AC auxiliary systems are typically used to supply loads such as transformer cooling, oil pumps, and load tap changers, circuit breaker air compressors and charging motors, outdoor device heaters,… Read more
Feb 14, 2018 | By Edvard Csanyi
Recommended and commonly applied protection for transformers
The protection that is recommended and commonly applied for transformers is summarized in the following figures. It should be noted and recognized that these are general recommendations, not strict. More… Read more
Jan 12, 2018 | By Edvard Csanyi
3 Bad Conditions That Cause False Differential Current In Power Transformer
When applying differential protection of power transformer, three bad conditions must be considered which can lead to unbalance to the currents applied to the relay (compared with the expected currents… Read more
Dec 27, 2017 | By Edvard Csanyi