Sepam - HV/MV Protection and control units (ENG) - Trinet

Use - commissioningCommissioning (cont’d)Microswitch SW1 and SW2settingsThe microswitch settings must be coherent with thechoices made in the status, phase CT ratioand VT ratio menus:c current input for 1 A / 5 A CT1 A secondary 5 A secondarySW2SW2v residual current measurement by sum of 3 currentsSW1c connection voltage inputv residual voltage measurement by sumSW1SW1v residual current measurement by corebalance CTSW1SW1c current input for CSP sensorcurrentsensor rangerated current of networkCSP30-300 A 30 36 45 60 75 90 120 150 180 225 300160-1600 A 160 192 240 320 400 480 640 800 960 1200 1600500-2500 A 500 600 750 1000 1250 1500 2000 2500SW2v no residual voltage measurementSW10 10 10 10 1v residual current measurement by sum of 3 currentsSW10 1 0 1Som10 10 1v residual voltage measurement by broken delta-startransformer0 10 10 10 10 10 1Som2v residual current measurement by core balance CTSW10 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 10 10 10 10 10 10 10 10 1ProtectionAccording to the type of Sepam 2000, the following functions are available:Locked rotor / excessive starting time (48/51 LR)Protection of motors that are liable to start with overloads or insufficient supplyvoltage and/or drive loads that are liable to become locked (e.g. crusher). It is anovercurrent protection that is only confirmed after a time delay which correspondsto the normal start time.Recommendation: use short, definite time.Negative sequence / unablance (46)Protection of equipment against overheating caused by an unbalanced powersupply, phase inversion or phase break, and against low levels of overcurrentbetween 2 phases.Recommendation: use IDMT curves.Neutral unbalance (50/51)Detection of unbalance current between the neutral points of doublestar-connected capacitor banks; unbalance current indicates that componentsof one of the capacitors are damaged.Rate of change of frequency (81R)Protection which calculates the rate of frequency variation and comparesit to a set point (used with uncoupling and load shedding).Machine differential (87M-87G)Fast, sensitive protection of motors and generators against internal faultsdue to damaged insulation. The protection is based on the principle of percentagedifferentials, i.e. starting current restraint to sustain stability in spite of its high levelof sensitivity.Thermal overload (49)Protetion of equipment against thermal damage caused by overloads. Thermaloverload is calculated according to a mathematical model, with 2 time constants,taking into account the effect of negative sequence current by means of anadjustable weighting coefficient:This function includes:v an adjustable setting to define equipment warm state (or alarm setting),v an adjustable tripping settingStarts per hour (66)Protection against overheating caused by too frequent starts. Checking of:v number of starts per hour,v number of consecutive warm starts (detected by the thermal overloadprotection),v number of consecutive cold starts. The protection inhibits energizingfor a preset time period when the permissible limits are reached.Tank frame leakage (50/51)Quick, selective detection of earth leakage current in transformer primary andsecondary windings. This overcurrent protection is associated with a currentsensor installed on the frame earthing connection. It calls for isolation of thetransformer tank.Phase overcurrent (50/51)Three-phase connection and equipment protection against phase-to-phase faults.The following types of time delay settings are available: definite, standard inverse,very inverse, extremely inverse and ultra inverse.Percentage type overcurrent (50/51 - 50N/51N)Detection of an unbalance current flowing between the two neutral pointsof double star mounted capacitor banks; this current indicates that the componentsof one of the banks are damaged.Directional overcurrent (67)Incomer protection, which provides quick, selective protection against upstreamfaults when there are several power supplies in parallel.SW12/12 Installation - Use - General characteristics - Testing