Basler DECS-250 Instruction Manual

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Basler DECS-250 Instruction Manual Manual pdf 107 page image

Stability TuningGenerator stability tuning in the DECS-250 is achieved through the calculation of PID parameters. PIDstands for Proportional, Integral, Derivative. The word proportional indicates that the response of theDECS-250 output is proportional or relative to the amount of change observed. Integral means that theDECS-250 output is proportional to the amount of time that a change is observed. Integral actioneliminates offset. Derivative means that the DECS-250 output is proportional to the required rate ofexcitation change. Derivative action avoids excitation overshoot.CautionAll stability tuning must be performed with no load on the system orequipment damage may occur.AVR ModeBESTCOMSPlus®Navigation Path: Settings Explorer, Operating Settings, Gain, AVRHMI Navigation Path: Settings, Operating Settings, Gains, AVR GainsTwo sets of PID settings are provided to optimize performance under two distinct operating conditions,such as with the power system stabilizer (PSS) in or out of service. A fast controller provides optimumtransient performance with the PSS in service while a slower controller can provide improved damping offirst swing oscillations the PSS offline. BESTCOMSPlus primary and secondary AVR stability settings areshown in Figure 96.Predefined Stability SettingsTwenty predefined setsA of stability settings are available with the DECS-250. Appropriate PID values areimplemented based on the nominal generator frequency selected (see the Configuration section of thismanual) and the combination of generator (T’do) and exciter (Texc) time constants selected from the gainoption list. (The default value for the exciter time constant is the generator time constant divided by six.)Additional settings are available to remove the effects of noise on numerical differentiation (AVRderivative time constant Td)B and set the voltage regulator gain level of the PID algorithm (Ka)C.Custom Stability SettingsStability tuning can be tailored for optimum generator transient performance. Selecting a primary gainoption of “custom” enables entry of custom proportional (Kp)D, integral (Ki)E, and derivative (Kd)F gains.When tuning the stability gain settings, consider the following guidelines• If the transient response has too much overshoot, decrease Kp. If the transient response is too slow,with little or no overshoot, increase Kp.• If the time to reach steady-state is too long, increase Ki.• If the transient response has too much ringing, increase Kd.CALL US TODAY1-888-POWER-58REQUEST A QUOTEparts@genpowerusa.comSHOP ONLINEwww.genpowerusa.comCALL US TODAY1-888-POWER-58REQUEST A QUOTEparts@genpowerusa.comSHOP ONLINEwww.genpowerusa.com