Microgrid power flow monitoring and control
AssigneeSchweitzer Engineering Laboratories, Inc.
InventorsAbdel Rahman Khatib, Niannian Cai
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Abstract
A microgrid power flow monitoring and control system is described herein. The control system may determine active and reactive power sharing shortage on the electric power delivery system. The control system may utilize the control strategies of generation units, such as ISO control, droop control and constant power control to estimate power flow within a microgrid or other isolated system. A control strategy of one or more generators may be modified based on the determined power flow.
Claims19
A method for evaluating a power flow on a bus, i, in at least a portion of an electric power delivery system to perform a control operation, comprising:
- obtaining power characteristic values of power on the bus, i, of the electric power delivery system, including at least a frequency value and a voltage value of the power on the bus, i;
- calculating a power characteristic-dependent load value based on at least one of the power characteristic values and a percentage of a load on the bus, i, that is power characteristic-dependent;
- obtaining data identifying at least one of an operating mode and a control mode of the electric power delivery system;
- calculating a control-operating value based on a product of a control-mode coefficient, βi, and an operating value, X, of at least one generator connected to the bus, i;
- obtaining data identifying an angle of the power on the bus, i;
- calculating a power generation reference value, PiRef, based on:
- a sum of the calculated power characteristic-dependent load value, the calculated control-operating value, and the obtained voltage value and
- the angle of the power on the bus, i;
- and,
- a shared vale Sv calculated to satisfy Sv=|Vi|Σn=1N|Yin∥Vn|cos (δi−δn−θin),
- where:
- |Vi| is the voltage magnitude on the bus, i,
- N represents a total number of busses in the electric power delivery system, such that n represents bus n, of the total N busses in the electric power delivery system during mathematical summation,
- |Yin| is the magnitude of a Y bus matrix element related to the bus, i, and bus n,
- θin is an angle of a Y bus matrix element related to the bus, i, and bus n,
- δi is an angle of the bus, i, and
- δn is an angle of bus n;
- and
- performing a control operation based on the calculated power generation reference value, PiRef.
A method for evaluating a power flow on a bus, i, in at least a portion of an electric power delivery system to perform a control operation, comprising:
- obtaining power characteristic values of power on the bus, i, of the electric power delivery system, including at least a frequency value and a voltage value of the power on the bus, i;
- calculating a power characteristic-dependent load value by:
- determining a percentage of the load on the bus, i, that varies quadratically with respect to the obtained power characteristic;
- determining a percentage of the load on the bus, i, that varies linearly with respect to the obtained power characteristic;
- determining a percentage of the load on the bus, i, that is power characteristic independent;
- and
- multiplying the active power load on the bus, i, at a nominal power characteristic multiplied by a function of (i) the percentage of the load on the bus, i, that varies quadratically with respect to the obtained power characteristic, (ii) the percentage of the load on the bus, i, that varies linearly with respect to the obtained power characteristic, and (iii) the percentage of the load on the bus, i, that is power characteristic independent;
- obtaining data identifying at least one of an operating mode and a control mode of the electric power delivery system;
- calculating a control-operating value based on a product of a control-mode coefficient, βi, and an operating value, X, of at least one generator connected to the bus, i;
- obtaining data identifying an angle of the power on the bus, i;
- calculating a power generation reference value, PiRef, based on:
- a sum of the calculated power characteristic-dependent load value, the calculated control-operating value, and the obtained voltage value and
- the angle of the power on the bus, I;
- and
- performing a control operation based on the calculated power generation reference value, PiRef.
Dependencies are inferred from the claim text.