ENGINEERING ARTICLES

INTELLIGENT : capable of sensing system overloads and rerouting power to prevent or minimize a potential outage; of working autonomously when conditions require resolution faster than humans can respond…and cooperatively in aligning the goals of utilities, consumers and regulators EFFICIENT: capable of meeting increased consumer demand without adding infrastructure ACCOMMODATING: accepting energy from virtually any fuel source including solar and wind as easily and transparently as coal and natural gas; capable of integrating any and all better ideas and technologies energy storage technologies, for example – as they are market-proven and ready to come online MOTIVATING: enabling real-time communication between the consumer and utility so consumers can tailor their energy consumption based on individual preferences, like price and/or environmental concerns OPPORTUNISTIC: creating new opportunities and markets by means of its ability to capitalize on plug-a...

A protective relay is a device that detects the fault and initiates the operation of the circuit breaker to isolate the defective element from the rest of the system. The relays detect the abnormal conditions in the electrical circuits by constantly measuring the electrical quantities which are different under normal and fault conditions. The electrical quantities which may change under fault conditions are voltage, current, frequency and phase angle. Through the changes in one or more of these quantities, the faults signal their presence, type and location to the protective relays. Having detected the fault, the relay operates to close the trip circuit of the breaker. This results in the opening of the breaker and disconnection of the faulty circuit. A typical relay circuit is shown in Figure. This diagram shows one phase of 3-phase system for simplicity. The relay circuit connections can be divided into three parts viz. First part is the primary winding of a cur...

The use of semi-conductors in place of mechanical switches is what makes a circuit “electronic,” because they enable electrical signals to be switched at extremely high speeds, which is not possible with mechanical circuits. There are many different semi-conductor. DIODE: Like a one-way valve for electrical current, this device enables only electrical current to pass through it in one direction–extremely useful by itself, but also the basis for all solid state electronics. LIGHT EMITTING DIODE (LED): This type of diode emits a small amount of light when electrical current passes through it. LIGHT DEPENDENT RESISTOR (LDR): This type of semi-conductor has a changing resistance, depending on the amount of light present. BIPOLAR JUNCTION TRANSISTOR (BJT): This is a current-driven electronic switch used for its fast switching properties. METAL-OXIDE SEMICONDUCTOR FIELD-EFFECT TRANSISTOR (MOSET): This is a voltage-driven electronic s...