Energy and Power
LV Surge Arresters In Action Against Lightning
The site consists of offices (computer hardware, lighting and heating unit), a security post (fire alarm, burglar alarm, access control, video surveillance) and three buildings for the manufacturing process on… Read more
Dec 29, 2015 | By Edvard
Energy and Power
Smart Ways To Cut Down The Influence Of Harmonics
There are three possible ways of suppressing or at least reducing the influence of harmonics. The fourth way is a special case. Contents: Reducing generated harmonic currents Modifying the installation… Read more
Dec 28, 2015 | By Edvard
High Voltage
Capacitive Voltage Transformers (CVT) For HV Measurements
Capacitive voltage transformers (CVTs) are used on higher voltage levels, starting from 66 kV and upwards. The type of the CVT is always a single-pole one, thus the connection is… Read more
Dec 26, 2015 | By Edvard
Electrical Lectures
Basic PLC program for control of a three-phase AC motor (for beginners)
While the lighting control system previously discussed is useful to explain basic PLC operation, a more practical, and only slightly more complex, application is start-stop control of an AC motor…. Read more
Dec 25, 2015 | By Edvard
Electric Motor
Five factors that mess up motor efficiency and how to improve it
It must be emphasised that the standard electric motor is already a very efficient device with efficiencies above 80% over most of the working range, rising to over 90% at… Read more
Dec 23, 2015 | By Edvard
Energy and Power
The Basics Of Circuit Breaker Tripping Units
The main objective of circuit breaker tripping units and protective functions in general is to detect faults and to selectively isolate faulted parts of the system. It must also permit… Read more
Dec 21, 2015 | By Edvard
Energy and Power
Learn To Interpret Single Line Diagram (SLD)
We usually depict the electrical distribution system by a graphic representation called a single line diagram (SLD). A single line can show all or part of a system. It is… Read more
Dec 19, 2015 | By Edvard
Energy and Power
The good ventilation of switchgear and transformer rooms
In order to design a good ventilation of switchgear and transformer rooms, the air in the room must meet various requirements. The most important is not to exceed the permissible… Read more
Dec 18, 2015 | By Edvard
Energy and Power
Distribution of the MV neutral conductor right to the loads
4-wire systems are characterized by distribution of the MV neutral conductor right to the loads. This type of distribution is used in the USA and in certain countries influenced by… Read more
Dec 16, 2015 | By Edvard
Energy and Power
The basics of primary medium voltage switchgear
Primary medium voltage switchgear represents an important part within the primary distribution substation functionality. The switchgear works as a connection node between the outgoing distribution feeders and the in-feeding power… Read more
Dec 14, 2015 | By Edvard
Metering
Protective relay – The brain that detects abnormal system conditions
For medium voltage circuit breaker applications, protective relay serve as the “brain” that detects abnormal system conditions and direct the circuit breaker to operate. They also serve to provide specialized… Read more
Dec 12, 2015 | By Edvard
Energy and Power
Real time reactive compensation – A case with 5 problems and solutions
A car equipment manufacturer’s plant in Concord (Ontario, Canada) is supplied by a transformer rated at 2000 kVA – 27.6 kV / 600 V – Yy – Ucc = 5.23 %. It… Read more
Dec 11, 2015 | By Edvard
Transformers
The Worst Transformer Inrush Current Occurs When…
When a transformer is first energized or reenergized after a short interruption, the transformer may draw inrush current from the system due to the core magnetization being out of sync… Read more
Dec 09, 2015 | By Edvard
Electric Motor
The Design Basics Of Motor Protection Circuit Breaker
Application-specific variations of the MCCB, these breakers combine the short-circuit and isolation functionality of the MCCB with the motor overcurrent protection of a traditional overload relay. MPCBs are UL 489 Listed… Read more
Dec 07, 2015 | By Edvard
Energy and Power
Learn How To Specify Current Transformers
Current transformers are used to supply information to the protective relays and/or current, power and energy metering “instruments”. For this purpose they must supply a secondary current proportional to the… Read more
Dec 05, 2015 | By Edvard
