Toshiba GR-200-5 Instruction Manual

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6F2T0207 (0.01)GRE200 (5,6)- 600 -Phase-angle variance (Δθ) (see Figure 4.5-4)The phase-angle variance of Vr and Vi (Δθ) is measured by the phase-angle variance-relayhaving the setting [SyncRy1-Angle]. If the following equations are satisfied, the SyncRy1-Angle relay determines that the phase-angle variance is inside the permissible range.Vr × Vi cos ∆θ > 0 (4.5-4)Vr × Vi sin(setting[SyncRy1-Angle]) ≥ Vr × Vi sin ∆θ (4.5-5)Frequency-variance (Δf)The frequency-variance of Vr and Vi (Δf) is measured by the frequency-variance relay havingthe setting [SyncRy1-df]. If the following equations are satisfied, the SyncRy1-df relaydetermines that the frequency-variance is inside the permissible range.∆f = |fVi − fVr| ≤ setting [SyncRy1-df] (4.5-6)where,fVr Frequency of VrfVi Frequency of ViΔf Frequency-variance between Vr and ViNotice and tipsIf the frequency-variance between the Vr and the Vi is shown very large, the SYNCHK mayfail to make the decision of the synchronism, although Off is set for the setting [SyncRy1-dfEN]to abandon to checking the frequency-variance. This is because; the vector passes the [SyncR1-Angle] zone very quickly. As a result, the SYNCHK relay may fail to issue the permissioncommand. To avoid the failure, the user has to set values for settings [SyncR1-Angle] and[SYNC01_TSYN] depending on the assumed frequency-variance (Δf):∆f > Setting [SyncR1-Angle]180° × Setting [SYNC01_TSYN] (4.5-7)where,Δf= Frequency-variance (or cycle-slip in Hertz)Tips: Cycles for the synchronism closure can be calculated:Cycle for synchronism = 1 ∆f[Hz]⁄ (4.5-8)Time length for getting a synchronism: