The essentials of directional overcurrent protection in electrical power grid

Why do we use directional overcurrent protection? When does fault current direction become important? Well, electrical power grid comprises a network of power stations, substations and transmission lines. As well… Read more

Jan 30, 2017 | Edvard

The influence of voltage unbalance on NEMA motor performance

Voltage unbalance can be more detrimental than voltage variation to motor performance and motor life. When the line voltages applied to a polyphase induction motor are not equal in magnitude… Read more

Jan 27, 2017 | Edvard

Transformer exterior inspection and tests you MUST perform periodically

Periodic transformer exterior inspection (visual) reveals important condition information. For example, valves positioned incorrectly, plugged radiators, stuck temperature indicator and level gauges, and noisy oil pumps or fans. Oil leaks… Read more

Jan 25, 2017 | Edvard

Twelve golden rules for specifying and implementing a good SCADA system

A successful SCADA specification and good installation depends on choosing and utilizing proven and reliable technology, with adequate and comprehensive training of all personnel in the operation of the system…. Read more

Jan 23, 2017 | Edvard

4 example calculations of compensation for reactive power

First, let’s say some words about basics of the reactive power in system. Reactive current arises in every electrical system. Not only large loads, but smaller loads as well require reactive… Read more

Jan 20, 2017 | Edvard

Considerations to take into account when designing PLC ladder logic

Motor control circuits are often implemented using ladder logic. It is so called because the schematic representation of the control circuit resembles a ladder with two vertical rails and a… Read more

Jan 18, 2017 | Edvard

Commissioning of protection relays using test equipment and software

Commissioning and maintenance With numerical protection relays commissioning and maintenance has become far less complicated as a result of the information provided by the devices as well as the integrated… Read more

Jan 16, 2017 | Edvard

Basic three phase power measurements explained in details

Although single-phase electricity is used to supply common domestic and office electrical appliances, three phase alternating current (a.c.) systems are almost universally used to distribute electrical power and to supply… Read more

Jan 13, 2017 | Edvard

Four design criteria for human machine interface (HMI) in a substation

With the introduction of IEDs (Intelligent Electronic Devices), the traditional switchboard interface is being replaced by Human Machine Interface (HMI) software loaded on computer hardware. The designer has a wide… Read more

Jan 11, 2017 | Edvard

Specifying energy efficient motor, cabling and local power transformer

Many energy saving actions can encourage specifiers and engineers to look closely at the savings which can be made by specifying an energy efficient version of a particular component. This… Read more

Jan 09, 2017 | Edvard

31 practical do’s and don’ts to avoid loud transformer humming

The user thinking of loud transformer humming (practically noise) should start at the conceptual stage. If he can, he must consider if he has a noise problem before he specifies… Read more

Jan 06, 2017 | Edvard

Selection of distribution transformers for supplying power to LV networks

The characteristic data of distribution transformers are determined by the requirements of the network. The effective power determined must be multiplied by the power factor cosφ to give the rated power… Read more

Jan 04, 2017 | Edvard

Respect Murphy’s Law and don’t remote control all systems via SCADA

Every technology has applications for which it seems admirably suited, other applications for which it seems only marginally suited, and a group of applications for which it simply should not… Read more

Jan 02, 2017 | Edvard