Power failure, local

Local power failure, such as a motor for a pump or compressor, or fan for an air cooler... 

This essentially means the failure of an individual drive of a pump, compressor, fan, and so on. Failure of a single motor does not always mean it will affect only one relief valve. Depending on the drive that fails, the relief can be substantial. The following situations should be considered carefully in evaluating the impact of local power failure ... 

This may create more serious problems than individual local power failure. The impact of a particular bus bar design and the motors connected to a particular bus bar are very important in estimating contingency. It is often preferred that the electrical engineer and process engineer work together to establish the design of the bus bar. 

Although the first industrial application of anodic protection was as recent as 1954, it is now widely used, particularly in the USA and USSR. This has been made possible by the recent development of equipment capable of the control of precise potentials at high current outputs. It has been applied to protect mild-steel vessels containing sulphuric acid as large as 49 m in diameter and 15 m high, and commercial equipment is available for use with tanks of capacities from 38 000 to 7 600000 litre . A properly designed anodic-protection system has been shown to be both effective and economically viable, but care must be taken to avoid power failure or the formation of local active-passive cells which lead to the breakdown of passivity and intense corrosion. 

Power will be purchased from a nearby company. (One of the major reasons for locating here was the presence of low-cost, plentiful power.) A gas-fired plant for 125 psig steam will be built. This must be able to supply enough power to operate agitators and cooling-water pumps associated with the reactors when there is a power failure. Gas will be purchased from a local company. Drinking water will be purchased from the community of Martins Ferry, Ohio. Process and cooling water will be obtained from the Ohio River. Both will require treatment before they can be used in the plant. 

Electronically—Procedures may be available from a terminal or printed on a local printer. In this case consideration must be given to possible power failure and the need for appropriate backup. In addition, the terminal should be located where it can be most conveniently viewed during an emergency, and users must be able to access the document easily. 

The operation of ECCS pumps is also possible from a local key lock hand switch and from the control room but automatic signals pre-empt all others. In the event of normal power failure while the system is operating or in the process of going into operation, the system will restart from the standby sources. All system alarms annunciate in the control room. 

Secondary spot network Simple inexpensive when available in a given area protects against local power interruptions no maintenance required by user Not available in all locations provides no protection from area-wide utihty failures provides no protection against transient disturbances or surge/sag conditions Virtually no loss, 100% efficient presents low impedance to the load no effect on frequency or harmonic ntent... 

Earthquakes can cause local soil failure, surface ruptures and structural damage of nuclear power plants. The most significant earthquake effects on plants or their structural components result from the seismic waves which propagate outwards in all directions from the earthquake focus. These different types of waves can cause significant ground movements up to several hundred miles from the source. The movements depend upon the intensity, sequence, duration and the frequency content of the earthquake-induced... 

Where motor operated valves (MOVs) or air operated valves (AOVs) are selected as ESDVs, they should, as a minimum, have backup activation power sources, and the utility service lines should be highly reliable and protected. It should noted that full motor operated and air operated ESDVs are not the same as fail safe spring return valves, even if frequent functional testing is undertaken. The reliability of an internal spring return actuator is considered better than a self-contained MOV or AOV with its own local power source and protection of cabling. This is because additional components of a MOV or AOV contribute to additional failure points and will also have a higher level or vulnerability from external events than an internal spring mechanism. 

In the early phase of the Ortsbatterie, the function of the telephone was dependent on the functionality of the battery at the subscriber s facility. The transition to the Amtsbatterie changed the situation in so far as an increasing number of connected subscribers were affected in case of battery failure. The battery became a central security element continuous availability became necessary. Today, subscribers are responsible for the functionality of their equipment again when additional functions (cordless telephones, answering machines) are used which need a local power supply. 

Some communities have created a system under which home care patients are transferred to local hospitals in anticipation of an electric power failure or flood disaster. Local fire departments will also assist in the event of a power failure or need for evacuation. Some electric power companies will arrange power generators available for 24-hour ventilator users in case of an electrical failure. 

Failure is considered both on a local basis i.e., loss of utihty supply to one item of equipment (e.g., electric power to a pump motor) and on a general basis i.e., loss of supply to all consuming equipment in a process unit (e.g., cooling water to all coolers and condensers). For the purpose of these pressure rehef design considerations, a process unit is defined as one which meets all the following criteria ... 

Generally, electricity is purchased from a local supplier. Power is required to generate motor drives for lighting and for general uses. Note tliat, in tlie typical distillation operation illustrated in Fig. 16.3.3, a power outage for the entire system would cause a less severe effect tlian failure of a reflux pump alone. 

Electrical failures are by far the most common. The most important safety measure is the installation of emergency lights, w hich will go on as soon as the power fails. Their batteries will automatically be recharged after the pow er comes back. They should be installed even in laboratories where w ork is normally performed only during the day. Such units are fairly expensive, but smaller ones made for home use are now available in hard-W are stores. A check should be made with local authorities as to whether these are permissible for industrial use. 

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