Tap position determination based on regular impedance characteristics
AssigneeSiemens Energy & Automation, Inc.
InventorCarl J. Laplace
Life of this patent
Estimating the term…
Abstract
A voltage regulator controller includes means for determining the tap position based on regulator impedance characteristics. In a preferred embodiment, the tap position determination system is embodied as part of an regulator designed to operate within a fixed percentage range of regulation (e.g. .+-.10%) with the identical number of turns between each of its series winding taps. In this environment, the regulator tap position is determined as a function of the regulator input voltage, the regulator output voltage, the regulator series winding current, system load power factor and internal regulator impedance.
Claims20
A voltage regulator controller for use with a multi-tap voltage regulator transformer capable of producing an output voltage from an input voltage and having a plurality of tap positions for adjusting the output voltage in discrete tap position steps, comprising:
- at least one sensor for generating a first scaled signal indicative of the load current of the multi-tap transformer;
- a plurality of scaling transformers for generating a second scaled signal indicative of the input voltage and a third scaled signal indicative of the output voltage of the multi-tap transformer;
- a random access memory having a look-up table formed thereon, the look up table including a cross reference between first data indicative of regular type and second data indicative of inherent electrical parameters of the multi-tap transformer and having program code for determining a position of the tap from the load current, the input voltage, the output voltage and the electrical parameters provided by the look up table;
- and,
- a microprocessor coupled to the random access memory, the at least one sensor and the plurality of scaling transformers for determining the tap position responsive to execution of the program code.
A method of determining tap position in a multi-tap voltage regulator transformer having a first terminal for receiving an input voltage, a plurality of tap positions for adjusting an output voltage in discrete tap position steps, and a second terminal for providing the output voltage to a load, comprising the steps of:
- measuring the input voltage;
- measuring the output voltage;
- measuring the magnitude of the regulator's series winding current;
- determining a power factor (pf) of the transformer;
- determining the regulator complex impedance at neutral;
- determining the regulator complex impedance for one of the discrete tap position steps;
- determining the maximum series winding compensation percentage;
- calculating the derived tap position as a function of the input voltage, the output voltage, the power factor, the series winding current, the regulator complex impedance at neutral, the regulator complex impedance for the one of the discrete tap position steps and the maximum series winding compensation percentage;
- and,
- operating the regulator tap changing mechanism based on tap change decisions which assume that the derived tap position is a current tap position.
A method of determining tap position in a multi-tap voltage regulator transformer having a first terminal for receiving and input voltage, a plurality of tap positions for adjusting an output voltage in discrete tap position steps, and a second terminal for providing the output voltage to a load, comprising the steps of:
- measuring the input voltage;
- measuring the output voltage;
- measuring the regulators' series winding current;
- reading, from a memory, stored information identifying inherent electrical characteristics of the multi-tap transformer;
- determining a power factor (pf) of the transformer;
- calculating the derived tap position as a function of the input voltage, the output voltage, the power factor, the series winding current and the inherent electrical parameters;
- and,
- operating the regulator tap changing mechanism based on tap change decisions which utilize the derived tap position as a current tap position.
A method of determining tap position in a multi-tap voltage regulator transformer of a type having plurality of tap positions for adjusting an output voltage in discrete tap position steps, comprising the steps of:
- reading, from a memory, stored information identifying inherent impedance characteristics of the multi-tap transformer;
- determining a calculated tap position as a function of the inherent impedance characteristics, measured regulator current values and measured regulator voltage values;
- and,
- operating the regulator tap changing mechanism based on tap change decisions which utilize the calculated tap position as a current tap position.
Dependencies are inferred from the claim text.