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Sectionalizer
In electric power distribution, a recloser, also known as autorecloser or automatic circuit recloser (ACR), is a switchgear designed for use on overhead electricity distribution networks to detect and interrupt transient faults. Reclosers are essentially rated circuit breakers with integrated current and voltage sensors and a protection relay, optimized for use as a protection asset. Commercial reclosers are governed by the IEC 62271-111/IEEE Std C37.60 and IEC 62271-200 standards. The three major classes of operating maximum voltage are 15.5 kV, 27 kV and 38 kV. For overhead electric power distribution networks, up to 80% of faults are transient, such as lightning strike, surges or foreign objects coming into contact with exposed distribution lines. Consequently, these transient faults can be resolved by a simple reclose operation. Reclosers are designed to handle a brief open-close duty cycle, where electrical engineers can optionally configure the number and timing of attem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Substation
A substation is a part of an electrical generation, transmission, and distribution system. Substations transform voltage from high to low, or the reverse, or perform any of several other important functions. Between the generating station and the consumer, electric power may flow through several substations at different voltage levels. A substation may include transformers to change voltage levels between high transmission voltages and lower distribution voltages, or at the interconnection of two different transmission voltages. They are a common component of the infrastructure. There are 55,000 substations in the United States. Substations are also occasionally known in some countries as switchyards. Substations may be owned and operated by an electrical utility, or may be owned by a large industrial or commercial customer. Generally substations are unattended, relying on SCADA for remote supervision and control. The word ''substation'' comes from the days before the distri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electricity Meter
file:Hydro quebec meter.JPG, North American domestic analog signal, analog (Galileo Ferraris, Ferraris disk) electricity meter. file:Transparent Electricity Meter found in Israel.JPG, Electricity meter with transparent plastic case (Israel) file:West Bengal State Electricity Distribution Company Limited electricity meter – Purulia, West Bengal, India.jpg, Electricity meter in West Bengal, IndiaAn electricity meter, electric meter, electrical meter, energy meter, or kilowatt-hour meter is a device that measures the amount of electric energy consumed by a House, residence, a business, or an electrically powered device over a time interval. Electric utility, Electric utilities use electric meters installed at customers' premises for electricity pricing, billing and monitoring purposes. They are typically calibrated in billing units, the most common one being the kilowatt hour (''kWh''). They are usually read once each billing period. When energy savings during certain periods ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power-flow Study
In power engineering, a power-flow study (also known as power-flow analysis or load-flow study) is a numerical analysis of the flow of electric power in an interconnected system. A power-flow study usually uses simplified notations such as a one-line diagram and per-unit system, and focuses on various aspects of AC power parameters, such as voltage, voltage angles, real power and reactive power. It analyzes the power systems in normal steady-state operation. Power-flow or load-flow studies are important for planning future expansion of power systems as well as in determining the best operation of existing systems. The principal information obtained from the power-flow study is the magnitude and phase angle of the voltage at each busbar, bus, and the real and reactive power flowing in each line. Commercial power systems are usually too complex to allow for hand solution of the power flow. Special-purpose network analyzer (AC power), network analyzers were built between 1929 and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating Expense
An operating expense (opex) is an ongoing cost for running a product, business, or system. Its counterpart, a '' capital expenditure'' (capex), is the cost of developing or providing non-consumable parts for the product or system. For example, the purchase of a photocopier involves capex, and the annual paper, toner, power and maintenance costs represents opex. For larger systems like businesses, opex may also include the cost of workers and facility expenses such as rent and utilities. Overview In business, an operating expense is a day-to-day expense such as sales and administration, or research & development, as opposed to production. In short, this is the money the business spends in order to turn inventory into throughput. On an income statement, "operating expenses" is the sum of a business's operating expenses for a period of time, such as a month or year. In throughput accounting, the cost accounting aspect of the theory of constraints (TOC), operating expense is th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Availability
In reliability engineering, the term availability has the following meanings: * The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, ''i.e.'' a random, time. * The probability that an item will operate satisfactorily at a given point in time when used under stated conditions in an ideal support environment. Normally high availability systems might be specified as 99.98%, 99.999% or 99.9996%. The converse, unavailability, is 1 minus the availability. Representation The simplest representation of availability (''A'') is a ratio of the expected value of the uptime of a system to the aggregate of the expected values of up and down time (that results in the "total amount of time" ''C'' of the observation window) : A = \frac = \frac Another equation for availability (''A'') is a ratio of the Mean Time To Failure (MTTF) and Mean Time Between Failure (MTBF), or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Circuit
A short circuit (sometimes abbreviated to short or s/c) is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit. The opposite of a short circuit is an open circuit, which is an infinite resistance (or very high impedance) between two nodes. Definition A short circuit is an abnormal connection between two nodes of an electric circuit intended to be at different voltages. This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion. Although usually the result of a fault, there are cases where short circuits are caused intentionally, for example, for the purpose of voltage-sensing crowbar circuit protectors. In circuit analysis, a ''short circuit'' is defined as a connection between two nodes that forces them to be at the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuse Cutout
{{Short description, Combination of a fuse and a switch In electrical distribution, a fuse cutout or cut-out fuse (often referred to as a cutout) is a combination of a Fuse (electrical), fuse and a switch, used in primary overhead feeder lines and taps to protect distribution transformers from Electric current, current surges and overloads. An overcurrent caused by a fault in the transformer or customer circuit will cause the fuse to melt and the switch mechanism to visibly open, disconnecting the transformer from the line. The device can also be opened manually by Lineman (technician), utility linemen standing on the ground and using a long insulating stick called a "hot stick". Components A cutout and fuse assembly consist of three major components: *The cutout body, an open frame that supports the fuse holder and a ribbed porcelain or polymer insulator that electrically isolates the conductive portions of the assembly from the support to which the insulator is fastened. *T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
