Directional overcurrent: It is operated when the fault drives the power to flow in a particular direction Opposite to the specified direction. Used in the protection of Bus bar, Generator, and Transformers.
Differential: The differential relay is set to trip when the phase difference of two or more identical electrical quantities exceeds the specified value. It can Protect Transformers and Generators from localized faults. Distance: This type of relay is operated based on the distance between the impedance of the fault and the position of the relay.
They are mostly used in the protection of transmission lines. Based On Characteristics These classifications are based on their tripping property Instantaneous relay: Activate the tripping immediately after the occurrence of a fault, there will be no time delay. Definite time relay: Activated only if the fault remains until a specific time.
If the line current exceeds the safe value, circuit breaker gets triggered. Voltage restraint over current relay: The relay is activated only if both the under-voltage and overcurrent conditions occur at the same time. Based on Application Primary relay Backup relay If the protection system fails the whole network might get collapsed so they use the backup relay.
Conclusion The numeric relays are mostly used in the generating stations and substations for automated protection. Wire-to-Board Solutions.
WR-FFC series pre-folded flat flexible cable are compact, thin, and light to save space. Learn more. Search now. Numerical relays are based on the use of microprocessors. The first numerical relays were released in A big difference between conventional electromechanical and static relays is how the relays are wired. Electromechanical and static relays have fixed wiring and the setting is manual. Numeric relays, on the other hand, are programmable relays where the characteristics and behavior can be programmed.
Most numerical relays are also multifunctional. Submit your inquiry and we will contact you. Learn more I agree. Navigate Search Login layouts-flyoutmenu-cart.
Search Search now. Rate this page General impression. Positive Negative. Your cart Learn more about shopping on ABB. Protection relays. Scope Modern protection relays Multifunctional protection Product benefits Provide continuity of power to consuments Protection of network assets Protection against life-threatening electrical incidents Product features Self-checking facility Low burden relays improve accuracy Fast fiber optical communication with substation LAN Adaptive relaying schemes Permit storage of historical data Time stamping.
What are the Advantages of Numerical Relays? Compact Size: Numerical relays are dependent only on one system for all approach and utilize indication on LCD for its activation, within a smaller space. An important fact to consider is that the digital protection can be made physically smaller when there is need for less panel wiring than equivalent functions implemented using analog tech.
Flexible : As the numerical relay depends on the software, it is easy to make customized modifications to achieve desired protection features. This in turn saves the cost for its user on replacing hardware. Upgrades are easy. Reliabile : Due the fewer connections, Numerical relays are more reliable. Multiple Characteristics of Relays: The range of operation within the traditional models is too narrow while numerical relays are diverse and adoptable.
Numerical relays have the feature of multi-tasking, which allows and strengthens different relay characteristics. As the relays provide better compatible protection, their efficiency is improved. All of this is achieved with the memory save feature in the microprocessor. As with a computer, a relay also has serial and parallel ports to link the relay to the substation's control and communication systems.
To extend the tripping command, the Auxiliary relays can be attached to the digital output contacts. For different types of safety, numerical relays are used and are graded based on characteristics, logic, parameters of action and application. Although they are categorized under different circumstances, their function remains the same, in the event of a fault in the electrical network, to enable the travel system.
Such classifications are made based on the relay's logical operation. Used for protection against transformers and feeders. Used for the safety of transformers, generators, and bus bars. It can protect transformers from localized faults and generators.
They are primarily used to safeguard transmission lines. These classifications are based on their tripping property. When the line current is higher than the safe value, the circuit breaker is triggered.
The entire network could crash if the security system fails, so they use the backup relay. And if the primary relay goes wrong, doing this would help us secure the machine. Numeric relays are often used for automatic safety in the generating stations and substations. Different components such as feeder, engine, generator, transmission line, transformers and bus bars can be secured by such relays. Each business has its own software that can help us communicate with their relays and program the security algorithm.
You can construct your own algorithm for security and feed it to the relay once you know about the parameter and the various types of faults that could occur in a power system. It doesn't take years of training and practice to become an expert in the defense of the power system to become one overnight. To become an expert, keep learning and keep on investigating. What is numerical protection relay? Numerical relay is actually the digital relay as a unit for which manufacturers has developed standardized hardware, which can be used in conjunction with suitably developed software to meet variety of production requirements and applications.
What is the difference between a relay and a fuse and a circuit breaker? A fuse is a protective device to limit the let through energy based on the current limit being exceeded. What is meant by numerical 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 microprocessor-type protective relays. What is numerical overcurrent relay? A 'Numerical over Current Relay' is a type of protective relay which operates when the load current exceeds a preset value. The overcurrent relay of IDMT is the relay that starts to operate after the intended time delay.
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