Energy and Power
Applications and characteristics of overcurrent potection relays (ANSI 50, 51)
Overcurrent relays are the most commonly-used protective relay type. Time-overcurrent relays are available with various timing characteristics to coordinate with other protective devices and to protect specific equipment. Instantaneous overcurrent relays have no inherent time delay and are used for fast short-circuit… Read more
Oct 08, 2014 | By Edvard Csanyi
Energy and Power
Rating Definitions Applied to Low Voltage Molded-Case Circuit Breaker (MCCB)
The molded-case circuit breaker is the “workhorse” for system protection 600V and below. A circuit breaker is a device designed to open and close by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when… Read more
Sep 19, 2014 | By Edvard Csanyi
Energy and Power
Rating Definitions Applied to Medium Voltage Circuit Breaker
The medium voltage circuit breaker is the device of choice when sophisticated system protection at the medium voltage level is required. Most modern medium voltage circuit breakers use a vacuum as the interrupting means, although sulfur-hexafluoride (SF6) based units still exist and in use. Medium… Read more
Sep 03, 2014 | By Edvard Csanyi
Energy and Power
5 most common critical power distribution topologies
In many of today’s mission-critical applications, ever-increasing reliability requirements are the norm. A critical part of this reliability is the reliability of the electric power distribution system for a given facility. Among the most demanding applications is that of a… Read more
Aug 15, 2014 | By Edvard Csanyi
High Voltage
An Example of Choosing 138 kV Line Circuit Breaker
To better understand a process of high voltage equipment selection, let’s discuss an example of choosing 138 kV Line #3 Circuit Breaker, shown in Figure 1, assuming that the following information about the system is available: The following information about… Read more
Jul 23, 2014 | By Edvard Csanyi
Power Substation
How To Locate Current Transformers in HV Substation
Current transformers are used for protection, instrumentation, metering and control. It is only the first function that has any bearing on the location of the current transformer. Ideally the current transformers should be on the power source side of the circuit… Read more
Mar 14, 2014 | By Edvard Csanyi
Energy and Power
Purposes and Examples of Safety Interlocking Devices
Most switchboards and motor control centres are fitted with a variety of electrical and mechanical safety interlocking devices. Their purposes are to protect against for example: Withdrawing the switching device while it is carrying load or fault current. Prevent the switching… Read more
Feb 05, 2014 | By Edvard Csanyi
Energy and Power
What’s Really Important When You’re Designing The Low Voltage Switchgear?
Here what’s important when you’re designing the low voltage switchgear: Device Application in the Supply Circuit Short-circuit strength Release (Trip Unit) Device Application in Supply Circuits (Coupling) Device Application in the Distribution Circuit Device Application in the Final Circuit The… Read more
Oct 07, 2013 | By Edvard Csanyi
Electric Motor
Sizing The DOL Motor Starter Parts (Contactor, Fuse, Circuit Breaker and Thermal Overload Relay)
In this technical article we’ll calculate the size of each part of DOL motor starter for the system voltage 415V, 5HP three phase household application induction motor, code A, motor efficiency 80%, motor RPM 750, power factor 0.8 and overload… Read more
Sep 11, 2013 | By Jignesh Parmar
High Voltage
Talking about HV shunt reactor switching (part 2)
Continued from first part: Talking About HV Shunt Reactor Switching (part 1) Scope (explained in previous part) Shunt reactors application (explained in previous part) Closing operation (explained in previous part) Opening operation Conclusions In the case of shunt reactors the… Read more
Jul 31, 2013 | By Nicola
High Voltage
Talking about HV shunt reactor switching (1)
These notes aim to give basic idea of the main criticalities related to HV shunt reactor switching, particularly in terms of voltage, and how such problems are faced and solved by modern switching technology. Content: Shunt reactors application Closing operation… Read more
Jul 29, 2013 | By Nicola
High Voltage
Commissioning of HV Panel – Operational and Functional Checkup
The main objective of the test is to check the proper operation function of the circuit breaker; in this test we do the following: This test is conducted by manual, Local and Remote. For the manual Operation test, we will… Read more
Jul 17, 2013 | By Edvard Csanyi
Low Voltage
Defining Size and Location of Capacitor in Electrical System (2)
Continued from part 1: Defining Size and Location of Capacitor in Electrical System (2) Size of circuit breaker (CB), fuse and conductor of capacitor bank: A. Thermal and magnetic setting of a circuit breaker B. Fuse selection C. Size of… Read more
Mar 11, 2013 | By Jignesh Parmar
Medium Voltage
Things You Should Know About Medium Voltage GIS
Environmental Concerns Safety Concerns Special Handling Procedures Installation Concerns Operation and Maintenance Concerns End of Life / Recycling Concerns Conclusion Medium voltage (5-38 kV) gas insulated switchgear (GIS) differs greatly from the medium voltage AIS – Air insulated switchgear commonly… Read more
Feb 20, 2013 | By Edvard Csanyi
High Voltage
High voltage substations overview (part 1)
High voltage substations are interconnection points within the power transmission and distribution systems between regions and countries. Different applications of substations lead to HV substations with and without power transformers: Step up from a generator voltage level to a high voltage… Read more
Jan 25, 2013 | By Emmanouil Angeladas
