Power engineers may also work on systems that do not connect to the grid. These systems are called off-grid power systems and may be used in preference to on-grid systems for a variety of reasons. For example, in remote locations it may be cheaper for a mine to generate its own power rather than pay for connection to the grid and in most mobile applications connection to the grid is simply not practical.
Power Engineering deals with the generation, transmission, distribution and utilization of electricity as well as the design of a range of related devices. These include transformers, electric generators, electric motors and power electronics.
In February 1990, the first computers from IBM to incorporate the POWER ISA were called the "RISC System/6000" or RS/6000. These RS/6000 computers were divided into two classes, workstations and servers, and hence introduced as the POWERstation and POWERserver. The RS/6000 CPU had 2 configurations, called the "RIOS-1" and "RIOS.9" (or more commonly the POWER1 CPU). A RIOS-1 configuration had a total of 10 discrete chips — an instruction cache chip, fixed-point chip, floating-point chip, 4 data L1 cache chips, storage control chip, input/output chips, and a clock chip. The lower cost RIOS.9 configuration had 8 discrete chips—an instruction cache chip, fixed-point chip, floating-point chip, 2 data cache chips, storage control chip, input/output chip, and a clock chip.
Power Surge was a DC Comics event in 2002 intended to promote the start of The Power Company, a new comic book series by writer Kurt Busiek, who also wrote all seven issues of Power Surge. Power Surge was composed of seven eponymous one-shot issues (although each story had its own title), each highlighting one of the seven primary members of the Power Company. Each story prominently featured the involvement of a classic, already-famous comic book character (with the 'classic' character looming much larger on the cover than the book's nominal main character).
Pneumatic systems use gasses under pressure to transmit power; compressed air is commonly used to operate pneumatic tools in factories and repair garages. A pneumatic wrench (for instance) is used to remove and install automotive tires far more quickly than could be done with standard manual hand tools. A pneumatic system was proposed by proponents of Edison's direct current as the basis of the power grid. Compressed air generated at Niagara Falls would drive far away generators of DC power. The War of Currents ended with alternating current (AC) as the only means of long distance power transmission.
In a direct current circuit, the power flowing to the load is proportional to the product of the current through the load and the potential drop across the load. Energy flows in one direction from the source to the load. In AC power, the voltage and current both vary approximately sinusoidally. When there is inductance or capacitance in the circuit, the voltage and current waveforms do not line up perfectly. The power flow has two components - one component flows from source to load and can perform work at the load; the other portion, known as "reactive power", is due to the delay between voltage and current, known as phase angle, and cannot do useful work at the load. It can be thought of as current that is arriving at the wrong time (too late or too early). To distinguish reactive power from active power, it is measured in units of "volt-amperes reactive", or var. These units can simplify to Watts but are left as var to denote that they represent no actual work output.
, called a subobject classifier. Although the term "power object" is sometimes used synonymously with exponential object
Electrical power transmission has replaced mechanical power transmission in all but the very shortest distances.
Monopoly power is an example of market failure which occurs when one or more of the participants has the ability to influence the price or other outcomes in some general or specialized market. The most commonly discussed form of market power is that of a monopoly, but other forms such as monopsony, and more moderate versions of these two extremes, exist.
The instantaneous power is then the limiting value of the average power as the time interval Δt approaches zero. :
Power transmission is usually performed with overhead lines as this is the most economical way to do so. Underground transmission by high-voltage cables is chosen in crowded urban areas and in high-voltage direct-current (HVDC) submarine connections.
As noted above, for many, power capabilities were the sole criterion. However, even under the more expansive tests, power retains a vital place.
Thermal power can be transported in pipelines containing a high heat capacity fluid such as oil or water as used in district heating systems, or by physically transporting material items, such as bottle cars, or in the ice trade.
In mathematics, the convolution power is the n-fold iteration of the convolution with itself. Thus if x is a function on Euclidean space R d and n is a natural number, then the convolution power is defined by
This differed from earlier writers, notably from Leopold von Ranke, who clearly had a different idea of the world situation. In his essay 'The Great Powers', written in 1833, von Ranke wrote: "If one could establish as a definition of a Great power that it must be able to maintain itself against all others, even when they are united, then Frederick has raised Prussia to that position." These positions have been the subject of criticism.
This aspect has received mixed treatment, with some confusion as to the degree of power required. Writers have approached the concept of great power with differing conceptualizations of the world situation, from multi-polarity to overwhelming hegemony. In his essay, 'French Diplomacy in the Postwar Period', the French historian Jean-Baptiste Duroselle spoke of the concept of multi-polarity: "A Great power is one which is capable of preserving its own independence against any other single power."
Power 2010 is attempting to get voters and candidates in the UK 2010 General Election to endorse these reforms by signing a personal pledge.
A power inverter will often have an overall power rating expressed in watts or kilowatts. This describes the power that will be available to the device the inverter is driving and, indirectly, the power that will be needed from the DC source. Smaller popular consumer and commercial devices designed to mimic line power typically range from 150 to 3000 watts.
Examples of soft power projection include:
Energy stored in capacitive or inductive elements of the network gives rise to reactive power flow. Reactive power flow strongly influences the voltage levels across the network. Voltage levels and reactive power flow must be carefully controlled to allow a power system to be operated within acceptable limits. A technique is known as reactive compensation is used to reduce apparent power flow to a load by reducing reactive power supplied from transmission lines and providing it locally. For example, to compensate an inductive load, a shunt capacitor is installed close to the load itself. This allows all reactive power needed by the load to be supplied by the capacitor and not have to be transferred over the transmission lines. This practice saves energy because it reduces the amount of energy that is required to be produced by the utility to do the same amount of work. Additionally, it allows for more efficient transmission line designs using smaller conductors or fewer bundled conductors and optimizing the design of transmission towers.