Substation AC Auxiliary Supply For Inessential Loads
The purpose of auxiliary power supply systems is to cater for the necessary energy for the operation of primary and secondary devices at the substation. The auxiliary power systems are normally divided in two categories,… Read more
Sep 30, 2015 | Edvard
FACTS Devices To Enhance Power System Performance
Flexible Alternating Current Transmission System (FACTS) simply refers to a combination of power electronics components with traditional power system components. They are intended to improve our power system reliability, power transfer capability, transient and dynamic… Read more
Sep 28, 2015 | sajna soman
Acceptable levels of distortion in the mains supply system
In the mains supply system, harmonic voltage distortion is the consequence of the flow of harmonic currents through the impedances in the power supply circuit connected to the converter. A typical power supply system at… Read more
Sep 26, 2015 | Edvard
Surge Protective Devices In TN Systems (Guide For Low Voltage Electricians)
For “protection against electric shock under fault conditions“ in TN systems, overcurrent and residual current devices have been approved. For the use of surge protective devices (SPDs) this means that these protective devices may only… Read more
Sep 25, 2015 | Edvard
Analysis of pole-mounted MV/LV transformer grounding
Let’s discuss in some detail the reasons for the grounding philosophy adopted for pole-mounted MV/LV transformer substations illustrated in Figure 0. Contents: LV grounding MV grounding Combined MV/LV grounding Separate MV/LV grounding MV electrode LV… Read more
Sep 23, 2015 | Edvard
Substation DC Auxiliary Supply – Battery And Charger Applications
Power substation can have one or several DC systems. Factors affecting the number of systems are the need of more than one voltage level and the need of duplicating systems. Today, normal DC auxiliary supply… Read more
Sep 21, 2015 | Edvard
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… Read more
Sep 19, 2015 | Edvard
Guidelines To Residential Room Lighting
Architects of development houses usually select the locations for switches, receptacles, and luminaires at a quality and price level determined by the builder. However, purchasers of architect-designed, custom-built homes usually have an opportunity to decide… Read more
Sep 18, 2015 | Edvard
4 Factors To Consider When Selecting a Sectionalizer
Sectionalizers are (beside overcurrent relays, reclosers and fuses) one of the most used for distribution system protection. A sectionalizer is a device that automatically isolates faulted sections of a distribution circuit once an upstream breaker… Read more
Sep 16, 2015 | Edvard
SF6 or Vacuum MV Circuit Breaker In Specific Switching Applications
Many years of experience in developing both SF6 and vacuum medium-voltage circuit breakers has yielded up ample evidence that neither of the two technologies is generally better than the other, and especially that they are… Read more
Sep 14, 2015 | Edvard
6 Customer Requirements For a Generator Regarding Power Demand
To select an on-site engine/generator sets (gensets), you’ll need to determine the power demand requirements which must be met under operating conditions, of course. Let’s talk about six recognized customer genset requirements regarding power demand //… Read more
Sep 12, 2015 | Edvard
5 Steps To Safely Shutdown a Large Generator
Normally, units are removed from service through operator initiation of distributed control system (DCS) commands or turbine trip buttons that shutdown the prime mover. Closure of steam or fuel valves will then initiate anti-motoring or… Read more
Sep 11, 2015 | Edvard
Modernizing An Old Hardwired Relay Logic With Modern PLC System
This technical article presents the modernization of a machine control system that will be changed from an old hardwired relay logic to PLC programmed logic. The field devices to be used will remain the same,… Read more
Sep 09, 2015 | Edvard
Selection of a suitable softstarter for application with conveyor belts
Conveyor belts can have a lot of different looks and directions of use. It is a typical constant torque load with low to high braking torque depending on how heavy it is loaded. Let’s take… Read more
Sep 07, 2015 | Edvard
The Basics of Electrical Bus Protections
When we examine electrical protection schemes, the best place to start is with electrical bus protections, as they are the easiest to protect. They utilize the fundamental concept of the overcurrent relay (Figure 1). An overcurrent relay is an… Read more
Sep 05, 2015 | Edvard
