COVER-RETAINER 4N3852 - Caterpillar

Parameters that are related to voltage regulation with reactive droop are listed below.:01 - Generator Output Voltage:02 - Ratio Of Output Voltage To Sensing Voltage:03 - Generator Type:04 - Rated Generator Output Current:05 - Current Transformer (CT) Voltage At Rated Generator Current:06 - Knee Frequency:15 - Voltage Gain:16 - Integral Gain:17 - Proportional Gain:22 - Droop/CCC Select (only on part number 155-xxxx and later):30 - Droop PercentageWhen generators operate in parallel, two primary objectives are for the generators to share both the real power requirements and the reactive power requirements of the system electrical load. The engine governors will control sharing of the real power requirements (kW) and the voltage regulator will control sharing of the reactive power requirements (KVAR) of the total system load. If the output voltage of one generator is slightly higher than the other generators, it will supply lagging reactive current to the other generators connected in the group. This current will circulate between generators, possibly causing ampere overloading. One method of minimizing this effect is to cause an individual generator's output voltage to sag, or "droop", in proportion to the lagging reactive current flow from it as measured with a current transformer (CT). For proper reactive load sharing, the regulator must know the rated generator output current (parameter :04), the CT voltage at rated generator current (parameter :05) and the desired percentage of output voltage droop (parameter :30) when the generator is at rated reactive output current.As reactive lagging generator output current increases, the regulator will cause the output voltage to droop (lower the voltage) proportionally. If the measured reactive output current is leading, the output voltage will rise. In either case, this action will tend to reduce the reactive current for better KVAR sharing with other units. The droop percentage (parameter :30) controls how much the generator output voltage will vary for a given amount of reactive current. It is important that the connected CT polarity is correct for the voltage to droop with lagging current flow. The line loss compensation voltage gain (parameter :15) function can adversely affect load sharing. For reactive droop to work properly, parameter :15 should be set to zero.