Alternatively, if the current plug setting is chosen as 125% (6.25 A), the fault current through the relay will be 50/6.25 = 8 A. Learn more about Scribd Membership. They have to be set to coordinate with both upstream and downstream relays. When deciding to apply IDMT relays to a network, a number of important points have to be considered. Applying IDMT in the System. ... (IDMT) over-current Relay is one in which the operating time is approximately inversely proportional to the fault current near pick-up value and then becomes constant above the pick-up value of the relay. Get contact details and address | ID: 21039685833 Firstly, it must be appreciated that IDMT relays cannot be considered in isolation. Calculate: (a) The secondary current, if the primary current is 840A; (b) The line current, when the IDMT sensed a current of 6A. 2) A/B group settings A relay that operates or picks up when its current exceeds a predetermined value (setting value) is called Over-current Relay. Tutorial B6 – IDMT Protection Relay Solution 1. Calculation of IDMT Over Current - Read online for free. mikro sdn bhd contents. It means that the trip time is inversely proportional to the fault current. Relay pickup current (A). Inverse Time Over Current is also referred to as Time Over Current (TOC), or Inverse Definite Minimum Time (IDMT). (IDMT) Relay Characteristics 1. Idmt Overcurrent Relay Characteristics ... manual v7 7 electrical substation mains. To set the IDMT characteristic of a SEPAM relay, the following parameters should be considered: 1) Type of current transformer and its rated current The primary and secondary rated current of the CTs (1A or 5A), will be determined in the general settings of the relay. Books. Accordingly, relay settings = current plug tap 5 A (100%) and time multiplier 0.8. Upload. Close suggestions. Read about company. Saved. Home. Search Search. IDMT (Inverse Definite Minimum Time) Relay Calculation Overcurrent and Earth Fault Relay Setting Setting calculation is separated for overcurrent and eart fault relay . Anjani Power Tech - Offering L&T MC31 ANX Idmt Relay, Model Number/Name: MC61 at Rs 8700/piece in New Delhi, Delhi. As shown in the figure, the 400/5A current transformer (CT) is connect to a protection IDMT relay. Calculation of IDMT Over Current Relay Settings (50/51/50N/51N) Calculation model for thermal relay Siemens 7SJ64 Select from the standard set of IEC and IEEE curves. Say current setting of the relay is 150 % therefore pick up current of the relay is 1 × 150% = 1.5 A. Step-3 Now we have to calculate PSM for the specified faulty current level. Sign In Join. The graph shows that eight From current setting we calculate the trick current of the relay. The trip time is calculated from the following parameters: Trip curve. 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