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Sequence Of Events Recorder
A sequence of events recorder (SER) is an intelligent standalone microprocessor based system, which monitors external inputs and records the time and sequence of the changes. Sequence of events recorders usually have an external time source such as a GPS or radio clock. When wired inputs change state, the time and state of each change is recorded. SERs enable rapid root cause analysis after multiple events have occurred due to the secure recording of the sequence of events in the order of occurrence. SERs are therefore utilized as a diagnostic tool to minimize plant downtime. SERs are often interfaced with a SCADA system, distributed control system (DCS),or programmable logic controller (PLC). SER reports are used by electrical engineers to analyze large and small electrical system blackouts. After the Northeast blackout of 2003, the North American Electric Reliability Corporation (NERC) specified that electrical system data should be time-tagged to the nearest millisecond. In 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Google Patents
Google Patents is a search engine from Google that indexes patents and patent applications. Contents Google Patents indexes more than 87 million patents and patent applications with full text from 17 patent offices, including: * United States Patent and Trademark Office (USPTO), * European Patent Office (EPO), * China's National Intellectual Property Administration (CNIPA), * Japan Patent Office (JPO), * Korean Intellectual Property Office (KIPO), * World Intellectual Property Organization (WIPO), * Deutsches Patent- und Markenamt (DPMA), * Canadian Intellectual Property Office (CIPO), * Rospatent, * Intellectual Property Office (United Kingdom), * National Institute of Industrial Property (France), * the Netherlands Patent Office, * offices of Spain, Belgium, Denmark, Finland, and Luxembourg. These documents include the entire collection of granted patents and published patent applications from each database (which belong to the public domain). US patent documents date back to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Clock
A radio clock or radio-controlled clock (RCC), and often (incorrectly) referred to as an atomic clock is a type of quartz clock or watch that is automatically synchronized to a time code transmitted by a radio transmitter connected to a time standard such as an atomic clock. Such a clock may be synchronized to the time sent by a single transmitter, such as many national or regional time transmitters, or may use the multiple transmitters used by satellite navigation systems such as Global Positioning System. Such systems may be used to automatically set clocks or for any purpose where accurate time is needed. RC clocks may include any feature available for a clock, such as alarm function, display of ambient temperature and humidity, broadcast radio reception, etc. One common style of radio-controlled clock uses time signals transmitted by dedicated terrestrial longwave radio transmitters, which emit a time code that can be demodulated and displayed by the radio controlled clock. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Root Cause Analysis
In science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for ... and engineering, root cause analysis (RCA) is a method of problem solving used for identifying the root causes of faults or problems. It is widely used in IT operations, manufacturing, telecommunications, Process control, industrial process control, accident analysis (e.g., in aviation, rail transport, or nuclear plants), medicine (for medical diagnosis), healthcare industry (e.g., for epidemiology), etc. Root cause analysis is a form of deductive inference since it requires an understanding of the underlying causal mechanisms of the potential root causes and the problem. RCA can be decomposed into four steps: * Identify and describe the problem clearly * Establish a timeline from the normal situation until the problem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence Of Events
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions. Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. 108 pages. Time in physics is operationally defined as "what a clock reads". The physical nature of time is addressed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCADA
Supervisory control and data acquisition (SCADA) is a control system architecture comprising computers, networked data communications and graphical user interfaces for high-level supervision of machines and processes. It also covers sensors and other devices, such as programmable logic controllers, which interface with process plant or machinery. Explanation The operator interfaces which enable monitoring and the issuing of process commands, like controller set point changes, are handled through the SCADA computer system. The subordinated operations, e.g. the real-time control logic or controller calculations, are performed by networked modules connected to the field sensors and actuators. The SCADA concept was developed to be a universal means of remote-access to a variety of local control modules, which could be from different manufacturers and allowing access through standard automation protocols. In practice, large SCADA systems have grown to become very similar to distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distributed Control System
A distributed control system (DCS) is a computerised control system for a process or plant usually with many control loops, in which autonomous controllers are distributed throughout the system, but there is no central operator supervisory control. This is in contrast to systems that use centralized controllers; either discrete controllers located at a central control room or within a central computer. The DCS concept increases reliability and reduces installation costs by localising control functions near the process plant, with remote monitoring and supervision. Distributed control systems first emerged in large, high value, safety critical process industries, and were attractive because the DCS manufacturer would supply both the local control level and central supervisory equipment as an integrated package, thus reducing design integration risk. Today the functionality of Supervisory control and data acquisition (SCADA) and DCS systems are very similar, but DCS tends to be u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmable Logic Controller
A programmable logic controller (PLC) or programmable controller is an industrial computer that has been ruggedized and adapted for the control of manufacturing processes, such as assembly lines, machines, robotic devices, or any activity that requires high reliability, ease of programming, and process fault diagnosis. Dick Morley is considered as the father of PLC as he had invented the first PLC, the Modicon 084, for General Motors in 1968. PLCs can range from small modular devices with tens of inputs and outputs (I/O), in a housing integral with the processor, to large rack-mounted modular devices with thousands of I/O, and which are often networked to other PLC and SCADA systems. They can be designed for many arrangements of digital and analog I/O, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory. PLCs were first devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northeast Blackout Of 2003
The Northeast blackout of 2003 was a widespread power outage throughout parts of the Northeastern and Midwestern United States, and most parts of the Canadian province of Ontario on Thursday, August 14, 2003, beginning just after 4:10 p.m. EDT. Most places restored power by midnight (within 7 hours), some as early as 6 p.m. on August 14 (within 2 hours), while the New York City Subway resumed limited services around 8 p.m. Full power was restored to New York City and Toronto on August 16. At the time, it was the world's second most widespread blackout in history, after the 1999 Southern Brazil blackout. The outage, which was much more widespread than the Northeast blackout of 1965, affected an estimated 10 million people in southern and central Ontario, and 45 million people in eight U.S. states. The blackout's proximate cause was a software bug in the alarm system at the control room of FirstEnergy, an Akron, Ohio–based company, which rendered operators una ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Electric Reliability Corporation
The North American Electric Reliability Corporation (NERC) is a nonprofit corporation based in Atlanta, Georgia, and formed on March 28, 2006, as the successor to the North American Electric Reliability Council (also known as NERC). The original NERC was formed on June 1, 1968, by the electric utility industry to promote the reliability and adequacy of bulk power transmission in the electric utility systems of North America. NERC's mission states that it is to "ensure the reliability of the North American bulk power system." NERC oversees six regional reliability entities and encompasses all of the interconnected power systems of Canada and the contiguous United States, as well as a portion of the Mexican state of Baja California. NERC's major responsibilities include working with all stakeholders to develop standards for power system operation, monitoring and enforcing compliance with those standards, assessing resource adequacy, and providing educational and training resour ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millisecond
A millisecond (from '' milli-'' and second; symbol: ms) is a unit of time in the International System of Units (SI) equal to one thousandth (0.001 or 10−3 or 1/1000) of a second and to 1000 microseconds. A unit of 10 milliseconds may be called a centisecond, and one of 100 milliseconds a decisecond, but these names are rarely used. To help compare orders of magnitude of different times, this page lists times between 10−3 seconds and 100 seconds (1 millisecond and one second). ''See also'' times of other orders of magnitude. Examples The Apollo Guidance Computer used metric units internally, with centiseconds used for time calculation and measurement. *1 millisecond (1 ms) – cycle time for frequency 1 kHz; duration of light for typical photo flash strobe; time taken for sound wave to travel about 34 cm; repetition interval of GPS C/A PN code *1 millisecond - time taken for light to travel 204.19 km in a single mode fiber optic cable for a wavelength o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Remote Terminal Unit
A remote terminal unit(RTU) is a microprocessor-controlled electronic device that interfaces objects in the physical world to a distributed control system or SCADA (supervisory control and data acquisition) system by transmitting telemetry data to a master system, and by using messages from the master supervisory system to control connected objects.Gordon R. Clarke, Deon Reynders, Edwin Wright,'' Practical modern SCADA Protocols: DNP3, 60870.5 and related systems'' Newnes, 2004 pages 19-21 Other terms that may be used for RTU are remote telemetry unit and remote telecontrol unit. Architecture An RTU monitors the field digital and analog parameters and transmits data to a SCADA Master Station. It runs setup software to connect data input streams to data output streams, define communication protocols, and troubleshoot installation problems in the field. An RTU may consist of one complex circuit card consisting of various sections needed to do a custom-fitted function, or may consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Protective Relay
In utility and industrial electric power transmission and distribution systems, a numerical relay is a computer-based system with software-based protection algorithms for the detection of electrical faults. Such relays are also termed as microprocessor type protective relays. They are functional replacements for electro-mechanical protective relays and may include many protection functions in one unit, as well as providing metering, communication, and self-test functions. Description and definition The digital protective relay is a protective relay that uses a microprocessor to analyze power system voltages, currents or other process quantities for the purpose of detection of faults in an electric power system or industrial process system. A digital protective relay may also be called a "numeric protective relay". It is also called numerical relay. Input processing Low voltage and low current signals (i.e., at the secondary of a voltage transformers and current transformers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
