ADVANTAGES OF SMART GRID

ADVANTAGES OF SMART GRID

By Engr. Aneel Kumar   May 26, 2017   No comments:

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-and-play innovation wherever and whenever appropriate

QUALITY-FOCUSED: capable of delivering the power quality necessary – free of sags, spikes, disturbances and interruptions – to power our increasingly digital economy and the data centers, computers and electronics necessary to make it run

RESILIENT: increasingly resistant to attack and natural disasters as it becomes more decentralized and reinforced with Smart Grid security protocols

GREEN: slowing the advance of global climate change and offering a genuine path toward significant environmental improvement

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WHAT IS PROTECTIVE RELAY

WHAT IS PROTECTIVE RELAY

By Engr. Aneel Kumar   May 20, 2017   No comments:

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.

1. First part is the primary winding of a current transformer (C.T.) which is connected in series with the line to be protected.
2. Second part consists of secondary winding of C.T. and the relay operating coil.
3. Third part is the tripping circuit which may be either ac or dc it consists of a source of supply, the trip coil of the circuit breaker and the relay stationary contacts.

When a short circuit occurs at point F on the transmission line, the current flowing in the line increases to an enormous value. This results in a heavy current flow through the relay coil, causing the relay to operate by closing its contacts. This in turn closes the trip circuit of the breaker, making the circuit breaker open and isolating the faulty section from the rest of the system. In this way, the relay ensures the safety of the circuit equipment from damage and normal working of the healthy portion of the system.

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TYPES OF SEMI-CONDUCTORS

TYPES OF SEMI-CONDUCTORS

By Engr. Aneel Kumar   May 20, 2017   No comments:

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 switch used for its fast switching properties, low resistance, and capability to be operated in a parallel circuit. These are the basis for most power amplifier circuits.

These devices all have multiple layers of positively and negatively charged silicon attached to a chip with conductive metal leads exposed for soldering into the circuit. Some transistors and MOSFETS have built-in diodes to protect them from reverse voltages and Back-EMF.

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