Energy and Power
Automatic transfer system explained in detail (operational requirements)
In a previous article I explained the role of the automatic transfer system and the operational requirements – three modes of operation: manual mode, automatic mode, and auto mode failure. Now let’s cover the following topics and try to explain the concept… Read more
Nov 21, 2015 | By Edvard Csanyi
Energy and Power
Automatic Transfer System (ATS) Explained in Details
Using the basic building blocks of utility power, system topology, on-site generation, and uninterruptible power supplies, the basic role of the automatic transfer system may now be defined. In this role, the Automatic Transfer System must display the following characteristics:… Read more
Nov 20, 2015 | By Edvard Csanyi
Energy and Power
Eight Most Common Schemes To Supply MV Switchboard
Medium voltage networks are made up of switchboards and the connections feeding them. Let’s take a look at the eight different supply modes of these medium voltage switchboards. We’ll start with the main power supply solutions of an MV switchboard, regardless… Read more
Oct 23, 2015 | By Edvard Csanyi
Electrical Lectures
Voltage Drop Calculations For Engineers – Beginners
Voltage drop calculations using the DC-resistance formula are not always accurate for AC circuits, especially for those with a less-than-unity power factor or for those that use conductors larger than 2 AWG. Table 1 allows engineers to perform simple ac voltage drop calculations…. Read more
Sep 19, 2015 | By Edvard Csanyi
Energy and Power
Things About MCBs That Every Low Voltage Electrician Should Know
Miniature circuit breaker – MCB is a thermo-magnetic device, meaning that it has two methods of circuit interruption. A thermal mechanism, usually a bi-metallic strip, provides protection against moderate overcurrent. The heating action of the current causes the bi-metallic strip… Read more
Aug 22, 2015 | By Edvard Csanyi
Energy and Power
Example for Coordination of Cascaded Circuit Breakers
A 440 V 60 Hz switchboard feeds a 4-wire distribution board for small loads such as socket outlets. The switchboard has a fault making capacity of 100kA rms. After applying diversity factors to the loads the total load current is… Read more
Jun 24, 2015 | By Edvard Csanyi
Energy and Power
How to achieve selective coordination of circuit breakers
Selective coordination is often referred to simply as coordination. Coordination is defined in NEC® 240.2 as: “The proper localization of a fault condition to restrict outages to the equipment affected, accomplished by the choice of selective fault-protective devices.” It is… Read more
Jun 08, 2015 | By Edvard Csanyi
Energy and Power
3 Overcurrent Protective Device Ratings You MUST Properly Select
In order for an overcurrent protective device to operate properly, the overcurrent protective device ratings must be properly selected. These ratings include: Voltage rating Ampere rating and Interrupting rating – Minimum Interrupting Rating. If the interrupting rating is not properly selected,… Read more
May 08, 2015 | By Edvard Csanyi
Maintenance
Maintenance and testing of overcurrent protective devices
When designing electrical distribution systems, required maintenance and testing of the overcurrent protective devices is a very important consideration. The electrical system reliability, component and circuit protection, and overall safety are directly related to the reliability and performance of the… Read more
May 04, 2015 | By Edvard Csanyi
Energy and Power
Ring Main Unit (RMU) as an important part of secondary distribution substations
Before getting into “What is RMU” question, let’s say a word about the distribution system where RMU is often used. Distribution systems encompass power lines that transport energy from the transmission network or other sources to consumers, along with the… Read more
Feb 11, 2015 | By Edvard Csanyi
Energy and Power
A real life analogy of the jurisdiction of the protection relay
Formally, a relay is a logical element which processes the inputs (mostly voltages and currents) from the system/apparatus and issues a trip decision if a fault within the protection relay‘s jurisdiction is detected. A conceptual diagram of relay is shown… Read more
Feb 09, 2015 | By Edvard Csanyi
Electrical Lectures
Miniature Circuit Breakers (MCBs) For Beginners
This technical article focuses on the widely used miniature circuit breakers rated for 240 V or less. These are smaller and lower-rated versions of industrial-grade molded-case circuit breakers rated for 600 V or less. These miniature breakers, called air circuit… Read more
Jan 26, 2015 | By Edvard Csanyi
Protection
An example of transformer overload and short circuit protection
Transformer protection consists of both overload protection and short circuit protection. Overload protection is usually accomplished via proper selection of the secondary overcurrent protective device. NEC Article 450 gives specific primary and secondary overcurrent device ratings that may not be… Read more
Jan 21, 2015 | By Edvard Csanyi
Energy and Power
Electrical life (durability) of LV circuit breakers due to the switching operations
According to the standard IEC 947-2, there is actually no defined stipulation regarding the requirements of electrical life of a circuit breaker. The numbers of switching operations which a circuit breaker under no-load, normal load, overload and short-circuit conditions has… Read more
Dec 01, 2014 | By Edvard Csanyi
Energy and Power
Let’s analyse phase-to-earth faults in a single-incomer power system
Power-system protection should detect faults and isolate the faulty parts of the power system while keeping the fault-free parts in operation. Protection units are chosen according to the power-system configuration (parallel operation of generators or transformers, loop or radial power system,… Read more
Oct 17, 2014 | By Edvard Csanyi
