Basic Required Functionality
Backup Functionality
Required Signalling Schemes
Available communication.
Supply (AC or DC?)
Operating Voltage on Inputs.
CT input 1A 5A or other?
How many CT inputs (Will it be used in Breaker and a Half arrangement)
Do you require one or 2 VT input.
Do you need sub cycle operation.
Current transformers (CTs) are used to monitor the current (or lack of) in high-voltage systems, and their secondary outputs controls the behaviour of protection-system relays. The CTs (1) reduce the current to values that match the current ratings of the protective relays, and (2) electrically-isolate the relays from the high-voltage system.
Relays are used in smart street lighting systems to control the on/off functionality of lights based on various inputs, such as ambient light levels or motion detection. They enable energy efficiency by allowing lights to dim or turn off when not needed, reducing electricity consumption. Additionally, relays enhance system reliability and can be integrated with smart city infrastructure for remote management and monitoring, improving overall operational efficiency.
kinds of electrical relays
relays which operate by signalling alarms notifying the type of the fault
Depending on the size of the transformer, it can be protected by fuses, thermal elements, or by a full relay protection package, which could include overcurrent relays, differential relays, and distance relays.
Victor H. Todd has written: 'Protective relays' -- subject(s): Electric relays
Current transformers (CTs) are used to monitor the current (or lack of) in high-voltage systems, and their secondary outputs controls the behaviour of protection-system relays. The CTs (1) reduce the current to values that match the current ratings of the protective relays, and (2) electrically-isolate the relays from the high-voltage system.
All solid state relays are relays, but not all relays are solid state relays. There are three basic kinds of (protective) relays I know of: electromechanical (rely on induced voltages and currents to spin disks or energize solenoids), solid state (built with solid state parts - basically prerequisites to microprocessors), and microprocessor based relays (fancy computers).
The DC supply may supply power to trip breakers, or to power the protective relays.
Heinz Clemens has written: 'Relaisschutztechnik in Elektroenergiesystemen' -- subject(s): Electric power systems, Protection, Protective relays
Auxiliary relay is a relay which will repeat the operations of protective relay such as tripping, time lag, breaking of trip circuit current, giving alarms and showing flags etc..Protective relay contacts are delicate and light weight hence it will not capable of carrying a large amount of current for a long period.protective relays do not have enough contacts to perform all the operations of protective scheme.Therefore auxiliary relays, auxiliary switches and repeat contacts are used to assist protective relays.
A protective relay is a device designed to trip a circuit breaker when a fault is detected. The first protective relays were electromagnetic devices, relying on coils operating on moving parts to provide detection of abnormal operating conditions such as over-current, over-voltage, reverse power flow, over- and under- frequency. Microprocessor-based digital protection relays now emulate the original devices, as well as providing types of protection and supervision impractical with electromechanical relays. In many cases a single microprocessor relay provides functions that would take two or more electromechanical devices. By combining several functions in one case, numerical relays also save capital cost and maintenance cost over electromechanical relays. However, due to their very long life span, tens of thousands of these "silent sentinels" are still protecting transmission lines and electrical apparatus all over the world. An important transmission line or generator unit will have cubicles dedicated to protection, with many individual electromechanical devices, or one or two microprocessor relays.
A protective relay is a complex electromechanical apparatus, often with more than one coil, designed to calculate operating conditions on an electrical circuit and trip circuit breakers when a fault was found. Unlike switching type relays with fixed and usually ill-defined operating voltage thresholds and operating times, protective relays had well-established, selectable, time/current (or other operating parameter) curves. Such relays were very elaborate, using arrays of induction disks, shaded-pole magnets, operating and restraint coils, solenoid-type operators, telephone-relay style contacts, and phase-shifting networks to allow the relay to respond to such conditions as over-current, over-voltage, reverse power flow, over- and under- frequency, and even distance relays that would trip for faults up to a certain distance away from a substation but not beyond that point. An important transmission line or generator unit would have had cubicles dedicated to protection, with a score of individual electromechanical devices. The various protective functions available on a given relay are denoted by standard ANSI Device Numbers. For example, a relay including function 51 would be a timed overcurrent protective relay. These protective relays provide various types of electrical protection by detecting abnormal conditions and isolating them from the rest of the electrical system by circuit breaker operation. Such relays may be located at the service entrance or at major load centers. http://en.wikipedia.org/wiki/Relay
relays are two type 1. Electromagnetic attraction relays. 2. Electromagnetic induction relays.
Relays are used in smart street lighting systems to control the on/off functionality of lights based on various inputs, such as ambient light levels or motion detection. They enable energy efficiency by allowing lights to dim or turn off when not needed, reducing electricity consumption. Additionally, relays enhance system reliability and can be integrated with smart city infrastructure for remote management and monitoring, improving overall operational efficiency.
1) protection of various ac and dc components 2)it can be used for differential protection 3)used as auxiliary relays in contact systems of protective relaying schemes
Under the hood. Not sure which side but it is where all the relays and electrical stuff is. It may be snapped into a protective cover so it is not in plain view.