It is determines the amount of time the breaker will carry a ground fault before tripping. Note: PSM is used for time Calculation only and not required to be entered in the Relay Setting. Distance protection calculation formulas and procedures 1. No trip for a current below 80% of the instantaneous setting, Trip for a current equal to 120% of the instantaneous setting. you can not reproduce,republish or communicate any of the content , including files downloadable from this website, without the permission of the copyright owner.The use of this content on any other websites breaches copyright Act. 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CR4 Thread Want To Know About Earth Fault And Over. 9 Ground fault Pick Up Amps setting If the ground fault exceeds the set level, “Pick Up Amps”, the GF time delay will begin. Change ). Fault Current = Fault mVA / Sq.root 3 * Rated voltage. ARCING FAULT CURRENT AND THE CRITERIA FOR SETTING GROUND. He has published numbers of Technical Articles in “Electrical Mirror”, “Electrical India”, “Lighting India”,”Smart Energy”, “Industrial Electrix”(Australian Power Publications) Magazines. Change ), You are commenting using your Twitter account. Please share some relay setting calculations excels ,pdf or doble or RIO test kit calculation files if you have any so that we could purchase it … Again, it should not be encroached by load. This site uses Akismet to reduce spam. He is Freelancer Programmer of Advance Excel and design useful Excel base Electrical Programs as per IS, NEC, IEC,IEEE codes. Ground fault currents are not transferred through delta-Wye transformer 1PH fault Current at 11 KV side when 2 transformers in service = 15.86 KA. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. It is determines the level of fault current that will actuate a trip with no time delay. June 1, 2017 Calculation of Relay Pick up current: While changing CT with new one our objective is to respond the relay within same time for either case for same value of fault current. Charging Current – Sympathetic tripping – Tripping Ratio ! Neutral-Grounding Resistor (NGR) Selection ! This technical article will cover the gathering of information needed to calculate protective relay settings, the setting calculations for the various protective functions, typical generator/turbine withstand times for abnormal operating conditions, and the math associated with various types of impedance elements. 17.3 Relay Co-ordination for Earth-fault Relay (contd..) Example a) Setting of Relay R1 Since the relay is on secondary side of transformer, our calculations will be referred to secondary side. What is the ref. Other fault Third 11kv line can pass through colony or it should pass along the main road only. Is these lines should be insulated when passing through already constructed area ? The instantaneous function will override the short-time function if the instantaneous Pickup is adjusted at the same or lower setting than the Short Time Pickup. Sequence networks and calculations are used to explain the setting of the overvoltage threshold for a single line-to-ground fault. Thanks a lot for the valuable information.. plz can you send calculation for AC-DB Bus Tie MCCB settings ( how to put settings for this MCCB) , Knowing that the two BUS’s that connected by this MCCB have OC/EF relay , but no CT for Bus Tie , so we use MCCB with built in OC /EF protections. Per common practice, the element provides independent reach settings for the and ground phase elements, TD21MP and TD21MG, respectively. Littelfuse ground-fault protection relays offer the needed protection against ground faults. what data should i collect to coordinate a series of pad mounted switches along the same feeder? Case-1 for Old CT: Old CT Ratio- 600/1 A, PSM – 1.05. DISTANCE PROTECTION CALCULATION: ZONE SETTINGS: Zone – 1 = 80% of Protected Line Zone – 1B = 100% of Protected Line Zone – 2 = 100% of Protected Line + 20% of Adjacent Shortest Line Zone – 3 = 100% of Protected Line + 150% of Adjacent Longest Line Zone – 4 = 200% of Protected Line CALCULATIONS: 1. 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