Metrosil.com.This domain provided by tucows.com at 1998-11-10T05:00:00Z (23 Years, 182 Days ago), expired at 2022-11-09T05:00:00Z (0 Years, 181 Days left). Site is running on IP address 172.67.142.55, host name 172.67.142.55 ( United States) ping response time 16ms Good ping. particular Metrosil design. Hence, when a sinusoidal voltage is applied across the Metrosil, the rms current drawn by the Metrosil is given by: I(rms) = 0.52 (V2V1) 1/ß C V1 = voltage (V, rms sinusoidal) This approximates the circuit conditions at the voltage setting. Details of the alternative Metrosil designs used with MFAC relays Purpose of Metrosil: It is Voltage Limiting Non-Linear Resistor. Non-Linear resistors are connected in parallel with the relay circuit to limit the peak voltage developed across the high impedance components during internal faults to a safe level below the insulation level of the current transformers, relay, and interconnecting leads. Metrosils can be specified with a diameter of 75mm or 150mm and 'C' values of 450, 900 or 1000. Metrosils of diameter 75mm have a thermal rating of 8kJ. Where a higher thermal rating is required Metrosils of 150mm diameter with a thermal rating of 33kJ should be used. The 7SG23 relay has an integral 75mm Metrosil with a constant 'C' value = 1000. Metrosil & resistor combination into protection panels employing high impedance differential schemes. Mounting is achieved by first fitting a special panel to the front of the cubicle. This panel is suitable for 19 inch rack or flush mounting. The separate Metrosil module is then installed from the rear of the cubicle & latched onto where, C and β are Metrosil constants. For satisfactory application of a non -linear resistor (Metrosil), its characteristic should be such that it complies with the following requ irements [6 Metrosil / Resistor Module 2V75 depicted in a size 8 rack or flush mount module Made in Australia The 2V75 Module provides a compact, simple & cost effective means of fitting a pre-wired Metrosil & resistor combination into protection panels employing high impedance differential schemes. 2.2.2 Stabilising Resistor The relay 7SJ602 requires a stabilising resistor to be connected in series for use as high impedance differential protection relay. This approach increases the relay circuit voltage setting. The resistor can be sized as follows: Vset −Vr =IsetRstab (4) where Rstab = stabilising resistance required Ø non-linear resistor (i.e. metrosil) For three-phase high impedance differential protection applications with 670 series three setting resistors (Rs) and three metrosils are assembled on one 4U high, 19" wide plate. The following two versions of such plate are available as optional accessories for 670 series: The 2V75 Metrosil module is rated well beyond the level required for normal protection operation & fault clearance times. 200W Stabilizing resistors The maximum short time power dissipation rating is 200W per stabilizing resistor (When set to the nominal resistance value). The 2V75 Metrosil module is rated well beyond the level required resistor External metrosil (if required) N.E.R. External stabilizing resistor External metrosil (if required) 28 27 28 27 MCAG 14 MCAG 14 Figure 1 Internal and external circuit diagram for unbiased differential protection of generators,reactors and synchronous motors using type MCAG 34 relay Figure 2 Type MCAG14 relays applied to restricted 2.3 Stabilizing Resistor The relay voltage setting range