METSO IOP331 Pulse output module

Generator Frequency High Limit 

• Sets maximum allowable generator frequency level. 

• If frequency is above High Limit, generator is not considered stable, and is unfit for breaker closure. 

Generator Frequency Low Limit 

• Sets minimum allowable generator frequency level. 

• If frequency is below Low Limit, generator is not considered stable, and is unfit for breaker closure.

Generator High/Low Frequency Limit Alarm

 • Even if the Alarm Set Points for the High/Low Limits are Disabled, the Speed Bias will not allow adjustment beyond these limits. 

• The same is true for the synchronizer, which will not allow a gen breaker closure if the High or Low Frequency limits are met or exceeded.

Speed/Frequency Mismatch Alarm 

• Compares engine speed (MPU) to generator frequency (PT signal) and alarms on a difference. 

• Used to indicate loss of MPU, or Loss of Generator Field Voltage. 

• If Start Sequencing is Disabled and no MPU is present, then this alarm compares Generator Frequency to Generator Frequency, so the Speed/ Frequency Mismatch Alarm will never alarm. 

CAUTION—LOSS OF MPU SIGNAL Woodward recommends that the Speed/Frequency Mismatch Alarm be set the same as the Overspeed Alarm to protect against the loss of the MPU signal.

Overcurrent Level 

• Range 5.0 – 30,000 A 

• Overcurrent level setting must be a greater value than the rated current of the generator 

• Set for per Phase Overcurrent 3 Phase sensing, selects phase with highest current

 • Uses Inverse Time Function as basis for overcurrent detection The overcurrent is based on AMP

•SECONDS. AMP

•SECONDS are determined by: Overcurrent Delay x (Overcurrent Level – Rated Current) 

• Per Phase Rated Current is determined by the Configuration menu Voltage Input—Wye or Delta Rated kVA Voltage Ref Per Phase Rated Current equals WYE voltage input: (Rated kVA / Voltage Ref) / 3 DELTA voltage input: (Rated kVA / Voltage Ref) / 1.732