Second Wind - Solutions - Encoderless Tap Position Reporting

Encoderless Tap Position Reporting

Tap Position Indicator

Phaser^® technology makes it possible to calculate tap position without using position encoders or any other interface to the Load Tap Changers (LTC). Regardless of type or manufacturer, and even if each phase has independent LTCs, Phasers and PhaserMaster can report precise tap positions for every feeder or transformer at any substation.

Substation SCADA is enhanced with good LTC tap position information. For instance, observation of how close feeder LTCs are to their positive limits tells a lot about remaining usable capacity of the lines. For another example, station reduction control may not function properly if a transformer LTC is already too close to the negative stop. And, of course, it would be nice to detect LTC failures promptly.

Nonetheless, tap position is often unavailable to the SCADA system. LTC controllers don't normally need the information to regulate, so they're frequently supplied without any means to monitor tap position. LTC position encoders and RTU interfaces of varying complexity and reliability are available as retrofits or new. However, since most utilities acquire and replace myriad types of LTC-equipped gear over long periods, the prospect of monitoring all of it can be daunting.

Phaser-based tap position monitoring is an entirely different proposition. The Phasers and PhaserMaster installed on substation feeders and busses for a typical distribution automation program are most of what's needed. The PhaserMaster gets primary voltages from the bus-monitoring Phasers and secondary voltages from the feeder-monitoring Phasers. PhaserMaster calculates the ratio of primary to secondary voltages for an initial estimate of the tap positions. Real and reactive power flow data from the feeder monitors are then processed using a mathematical model of the transformers (derived from nameplate data) to calculate the voltage drops in the transformer windings. Finally, the voltage ratio and voltage drop data are combined to calculate the actual tap position. PhaserMaster communicates the tap positions along with other Phaser data to the SCADA system. This information provides powerful leverage utilities need to maximize existing assets.


	Remote Wind Data Collection
	Power Performance Testing
	Integrating Met Data into Windfarm SCADA
	Autopilot Windfarm Control
	Forecasting Windfarm Production
	Windfarm Substation Monitoring
	Windfarm FAA Lights Monitoring
	Windfarm Output Curtailment
	Turbine Control and Monitoring with the Phaser
	Paralleling Transformers with the Phaser
	Measure Electrode Usage with the Phaser
	Translate Legacy Protocol with the Phaser
	Encoderless Tap Position Reporting


	Encoderless Tap Position Reporting (pdf)
	Tap Position Reporting Demonstration (pdf)