Iec 60255 trip curves

IEC 60255-3

The test module supports directional sector definition and any number of line, ground, positive sequence, negative sequence, and zero sequence elements. In Overcurrent, the set of test shots can be defined concurrently for all desired fault loops. This is possible for the following fault types:. This includes all of the elements which respond to the type of fault applied. Variants of these characteristics support commonly used relay types. Additional variants may be added to the template file, including curves digitized with the Overcurrent Characteristics Grabber. PTL test templates add relay-specific support by mapping the relay settings to the overcurrent module parameters and providing sample test sequences. Training Toggle Dropdown. Customer Login. Choose Application. Protection testing Choose Category. Choose Category. JavaScript not active You have disabled JavaScript. Please enable JavaScript to make use of all the features we offer. Need more details? Get a quotation? Request for a demo? E-mail Contact someone else. Contact us News Press Legal Imprint. All products. OMICRON serves the electrical power industry with innovative products and services for testing, diagnostics and monitoring of assets worldwide. We help to make the generation, transmission and distribution of electricity safe and reliable. You are using an outdated browser version. Please upgrade your browser or use another browser to view this page correctly.


Electromechanical relays have been the traditional backbone of electrical protection systems. While over recent years these have been replaced by microprocessor based numerical devices, there are still many older electromechanical relays in service. Mechanical relays developed in the s were the first form of electrical protection. While still being reliable and widely used these were superseded by static relays in the early s. Static relays have no moving parts hence the name and operated on the basis of analogue circuitry. More recently static relays have been superseded by first digital relays and now numerical microprocessor based devices. Each characteristic can be calculated from:. Relay characteristics are sometimes classified according to the tripping time at 10 times the setting current i. Tripping times for the various relays are:. These are given by:. An Amp breaker protected by relay with Standard Inverse characteristic. The relay pick-up current value is set at 0. What will be the tripping time? If you have the 3sec relay's trip curve, you can just multiply the time with 1. That is the time for the 1. The company history has changed over the last few years. Recently the company has now been acquired by Areva. If current transformers are connected in a residual circuit, saturation of one or more of the transformers during transient events may result in large spill currents. Particularly with high impedance relays, this may cause the the relay to falsely operate. To achieve stability under these conditions, stabilising resistor resistors are added to increase the minimum relay operating voltage. Note: The power rating of the stabilising resistor should be chosen taking into consideration the expected magnitude and duration of the current through the resistor. Steven has over twenty five years experience working on some of the largest construction projects. He has a deep technical understanding of electrical engineering and is keen to share this knowledge. About the author. Can you please answer A ACB is set at 0. Joby, I've added an example to the post using your values and also a new calculation tool see the example for the link. Let me know if you see anything wrong. Hello Mr. Im having some trouble to understand the exact terms i have to put in the form. If i have a relay with A Iprimary and 1 A as Isecondary, and i establish a pickup I of 7A 7 times my In thats is 1Aand then i inject 8 A trough the relay in the secondary. What shall i put in the form? If i do so i get 5, 24 sec of trip, and im doing the test physically and the machine indicates 2,01 sec. So im putting something wrong in the form.

What is meant by B, C, D, K and Z curves in MCBs?

Log In. Thank you for helping keep Eng-Tips Forums free from inappropriate posts. The Eng-Tips staff will check this out and take appropriate action. Click Here to join Eng-Tips and talk with other members! Already a Member? Join your peers on the Internet's largest technical engineering professional community. It's easy to join and it's free. Register now while it's still free! Already a member? Close this window and log in. Are you an Engineering professional? Join Eng-Tips Forums! Join Us! By joining you are opting in to receive e-mail. Promoting, selling, recruiting, coursework and thesis posting is forbidden. Students Click Here. Related Projects. Then what are "IAC" relay curves. Could anybody explain 1 For what does IAC stand for? IAC is a General Electric electromechanical overcurrent relay. Characteristic curves of electromechanical overcurrent relays are the result of electrommagnetic and spring torques, and do not follow ANSI or IEC equations. The characteristic curves of electromechanical relays are developed by testing.

Time/Current curves

Page of Go. Page - Figure P used to protect an autot Page Page - Example 3: Autotransformer with Unloaded Page - Figure Unloaded delta - current dist Page - Setting Guidelines for Short-Interconnec Page - Figure Single bus differential prote Page - Figure Shunt Reactor single line dia Page - Setting Guidelines for Reference Vector Page - Figure Automatic selection of distu Page - Figure Configuration file extractio Page - Performance of Frequency Protection Func Page - Performance of Monitoring and Control Fu GE Energy Connections. Table of Contents. Micom p40 agile single br eaker multi-end current differential ied non distance pages. Feeder protection system feeder protection and control pages. L90 line current differential system ur series pages. Page 4 Contents P64x 4. Page 9 P64x Contents 2. Page 10 Contents P64x 4. Page 12 Contents P64x 6. Page 17 P64x Contents Page 20 Differential protection blocking mechanisms Figure Triple slope characteristic Figure P used to protect a two winding transformer Figure P used to protect an autotransformer with loaded delta winding Figure P used to protect an autotransformer with unloaded delta winding Figure Unloaded delta — The level at which this manual is written assumes that you are already familiar with protection engineering and have experience in this discipline. The description of principles and theory is limited to that which is necessary to understand the product. Page Nomenclature Some of these terms are well-known industry-specific terms while others may be special product- specific terms used by GE. The first instance of any acronym or term used in a particular chapter is explained.

Electromechanical Relays

MCB Miniature circuit breaker is a re-settable device designed to protect a circuit from short circuits and overcurrents. Trip current rating is the minimum current at which the MCB will trip instantaneously. It is required that the trip current must persist for 0. The trip curve, also known as I-t tripping characteristic consists of two sections viz, overload section and short circuit section. Overload section describes the trip time required for various levels of overload currents and the short circuit section describes the instantaneous trip current level of MCB. These MCBs are suitable for cable protection. MCB with class C trip characteristics trips instantaneously when the current flowing through it reaches between 5 to 10 times the rated current. Suitable Domestic and residential applications and electromagnetic starting loads with medium starting currents. Suitable for inductive and motor loads with high starting currents. MCB with class K trip characteristics trips instantaneously when the current flowing through it reaches between 8 to 12 times the rated current. Suitable for inductive and motor loads with high inrush currents. These type of MCBs are highly sensitive to short circuit and are used for the protection of highly sensitive devices such as semiconductor devices. As like Class Z MCBs, these are also highly sensitive to short circuit and are used for the protection of semiconductor devices. MCBs with trip curve class B and trip curve class C are the most commonly used ones. Class C MCBs can be found in the lighting power distribution boards in residential and commercial buildings. It trips as soon as the current rises between 5 to 10 times its rated current. It trips as soon as the current rises between 3 to 5 times its rated current. In some applications, frequent current peaks occur for a very short period ms to 2s. For such applications, class Z type MCBs shall be used. Class Z type MCBs are used in circuits with semiconductor devices.

LSIG Trip Unit

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