3 earthing fault typologies and connection of the CB poles in a DC network
In order to break a short-circuit current in a d.c. system, it is necessary to connect the circuit breaker (CB) poles in a suitable way. To carry out this operation,… Read more
Jun 05, 2017 | By Edvard Csanyi
Twelve installation tips for implementing a good residual protection
All installations have an earth leakage current that is mainly due to the conductor’s capacitive leakage and to anti-parasitic or EMI filtering capacitors, for example class I equipment. The sum… Read more
Jun 02, 2017 | By Edvard Csanyi
Eight typical transformer protection schemes with correctly selected relays
This technical article shows application hints for typical transformer protection schemes where SIPROTEC 4 relays are used. Some of applications are small and large transformer infeed, dual infeed with single… Read more
May 31, 2017 | By Edvard Csanyi
Auto-reclose schemes for re-energising the line after a fault trip
Faults on overhead lines fall into one of three categories: transient, semi-permanent and permanent. 80-90% of faults on any overhead line network are transient in nature. The remaining 10%-20% of… Read more
May 15, 2017 | By Edvard Csanyi
Current sensors as the eyes of RCD and tips for their correct installation
All residual current devices are made up of at least two components. First component act as the eyes of RCD – sensors – must be able to supply an electrical signal… Read more
May 12, 2017 | By Edvard Csanyi
Protection of capacitor banks by fuses during energization and operation
Stress specific to the protection of capacitor banks by fuses, which is addressed in IEC 60549, can be divided into two types: Stress during bank energization (the inrush current, which is very… Read more
May 01, 2017 | By Edvard Csanyi
Why and where do internal faults happen in substation transformers
Transformers are subjected to many external electrical stresses from both upstream and downstream that can lead directly to internal fault(s). The consequences of any failure can be very great in… Read more
Apr 28, 2017 | By Edvard Csanyi
The most frequent errors in specifying current transformers (CTs)
Current transformers (CTs) form an essential link within the protection chain of electrical networks. Their specification, even if it is handled by specialists, often includes errors and is insufficiently optimized…. Read more
Apr 24, 2017 | By Edvard Csanyi
Thumb rules for surge arrester installation in different earthing systems
A variety of documents deal with the subject of surge arrester installation: for example in France, standard NF C 15-531 focuses on the installation rules of LV surge arresters, and… Read more
Apr 17, 2017 | By Edvard Csanyi
Circuit breaker selections for low voltage installation (with discrimination)
The LV installation which forms the subject of this study is shown in figure 1 above. This study includes discrimination and coordination of protection between the LV equipment and the… Read more
Apr 14, 2017 | By Edvard Csanyi
Six network operating conditions under which ferroresonance can occur
Due to the multitude of various sources of capacitances and non-linear inductances in a real power network and the wide range of operating conditions, configurations under which ferroresonance can occur… Read more
Apr 12, 2017 | By Edvard Csanyi
8 essential relay operating principles of catching faults
In general, as faults (short circuits) occur, currents increase in magnitude, and voltages go down. Besides these magnitude changes of the AC quantities, other changes may occur in one or… Read more
Apr 10, 2017 | By Edvard Csanyi
Three main techniques for mitigating step and touch potential hazards
Mitigating step and touch potential hazards is usually accomplished through one or more of the following three main techniques. Understanding the proper application of discussed techniques is the key to… Read more
Apr 07, 2017 | By Edvard Csanyi
Two main functions of an earth electrode and its installation parameters
The prime function of an earth electrode is the protection of persons. That’s it. It is a fact that we live on Earth! And it is vital to earth exposed… Read more
Apr 03, 2017 | By Edvard Csanyi
Five protection relay types used to detect grid disturbances and isolating
Consider a medium voltage distribution system having local generation (e.g., captive power generation) as shown in figure 1 which is also synchronized with the grid. During grid disturbance, if plant generators… Read more
Mar 29, 2017 | By Edvard Csanyi