System and method for modelling load in an electrical power network

Patent metadata

Field	Value
Publication number	US-9829880-B2
Application number	US-201414548699-A
Country	US
Kind code	B2
Filing date	Nov 20, 2014
Priority date	Nov 20, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A method for modelling load in a power grid is provided. The method includes obtaining measurement data from a measurement device in the power grid, identifying one or more voltage adjustment events in the power grid from the measurement data, and generating a load model based on one or more voltage factors computed using the one or more voltage adjustment events.

First claim

The invention claimed is:

1. A method for modelling load in a power grid comprising:
obtaining measurement data from a measurement device in the power grid;
identifying one or more voltage adjustment events in the power grid from the measurement data, wherein a voltage adjustment event comprises any change in voltage at a particular location in the power grid between a particular time instant and a previous time instant;
generating a load model based on one or more voltage factors computed using the one or more voltage adjustment event;
wherein one or more voltage factors include a voltage sensitivity factor, where the voltage sensitivity factor is a derivative of power with respect to voltage; and
wherein generating the load model comprises utilizing a recursive least mean square filter to recursively determine a constant impedance load coefficient (K z ), a constant current load coefficient (K i ), and a constant power load coefficient (K p ) of a ZIP load model based on a forgetting factor and a weighing factor.

2. The method of claim 1 , wherein obtaining the measurement data comprises obtaining power, voltage, and current from one or more locations in power grid.

3. The method of claim 2 , wherein obtaining the power, the voltage and the current from one or more locations in the power grid comprises obtaining the power, the voltage and the current from aggregated loads in the power grid.

4. The method of claim 3 , further comprising aggregating individual loads in the power grid based on a predefined criteria for obtaining the power, the voltage and the current in the power grid.

5. The method of claim 1 , further comprising determining a second set of load modelling parameters based on a first set of load modelling parameters and the one or more voltage adjustments.

6. The method of claim 5 , further comprising updating a load model library with the second set of load modelling parameters.

7. The method of claim 1 , wherein generating the load model based on one or more voltage factors generating the load model based on a voltage dependency.

8. The method of claim 7 , further comprising determining the voltage dependency using a second set of load modelling parameters.

9. The method of claim 1 , wherein generating the load model comprises generating a static load model.

10. A system for generating a load model for a power grid comprising:
a measurement device for obtaining measurement data in the power grid;
an event filter configured to identify one or more voltage adjustment events in the power grid from the measurement data, wherein a voltage adjustment event comprises any change in voltage at a particular location in the power grid between a particular time instant and a previous time instant;
a load modelling unit configured to generate a load model based on one or more voltage factors computed using the one or more voltage adjustment events;
wherein one or more voltage fact include a voltage sensitivity factor, where the voltage sensitivity factor is a derivative of power with respect to voltage; and
wherein generating the load model comprises utilizing a recursive least mean square filter to recursively determine a constant impedance load coefficient (K z ), a constant current load coefficient (K i ), and a constant power load coefficient (K p ) of a ZIP load model based on a forgetting factor and a weighing factor.

11. The system of claim 10 , wherein the measurement device comprises a supervisory control and data acquisition (SCADA) unit, a remote terminal unit (RTU), a phasor measurement unit (PMU), an advanced metering infrastructure (AMI) meter, a power factor meter, a power quality meter, or a combination thereof.

12. The system of claim 10 , wherein the measurement data comprises power, a voltage and a current of one or more locations in the power grid.

13. The system of claim 10 , wherein the load modelling unit and the event filter are deployed independently in the power grid, or deployed on a transmission system, a distribution system or a combination thereof in the power grid.

14. The system of claim 10 , further comprising a load model library for storing load modelling parameters for each of a plurality of corresponding clusters.

15. The system of claim 14 wherein each of the plurality of cluster comprises at least one of a season, a day of the week, a time of the day, a temperature at the time of the day, or a combination thereof.

16. The system of claim 10 , further comprising a recursive least mean square filter configured to determine a second set of load modelling parameters based on the first set of load modelling parameters and the one or more voltage adjustment events.

17. The system of claim 10 , further comprising a feedback loop configured to update a load model library with a second set of load modelling parameters.

18. A non-transitory computer readable medium, having instructions stored thereon which, when executed, causes a load modelling system having a measurement device, an event filter and a load modelling unit to perform a method, the method comprising:
obtaining measurement data from the measurement device in the power grid;
identifying one or more voltage adjustment events in the power grid from the measurement data, wherein a voltage adjustment event comprises any change in voltage at a particular location in the power grid between a particular time instant and a previous time instant;
obtaining a first set of load modelling parameters from a load model library;
determining a second set of load modelling parameters based on the first set of load modelling parameters and the one or more voltage adjustment events using a recursive least mean square filter;
determining one or more voltage factors for the power grid using the second set of load modelling parameters;
generating a load model based on one or more voltage factors for the power grid;
updating the load model library with the second set of load modelling parameters;
wherein one or more voltage factors include a voltage sensitivity factor, where the voltage sensitivity factor is a derivative of power with respect to voltage; and
wherein generating the load model comprises utilizing a recursive least mean square filter to recursively determine a constant impedance load coefficient (K z ), a constant current load coefficient (K i ), and a constant power load coefficient (K p ) of a ZIP load model based on a forgetting factor and a weighing factor.

19. The method of claim 1 , wherein identifying one or more voltage adjustment events includes satisfying conditions (i) (∂V)>V th , and (ii) (∂P*∂V>0), where V th is a predefined voltage threshold, and (∂V) and (∂P) are differences between a voltage and active power measured at the particular location at the first time instant and the previous time instant respectively.

20. The method of claim 1 , wherein identifying one or more voltage adjustment events includes satisfying conditions (i) (∂V)>V th , (ii) (∂P*∂V>0), and (iii) (∂Q*∂V>0), where V th is a predefined voltage threshold, and (∂V), (∂P) and, (∂Q) are differences between a voltage, active power and reactive power measured at the particular location at the first time instant and the previous time instant respectively.

Assignees

• Gen Electric

Inventors

• Baone Chaitanya Ashok
• Premerlani William James
• Pan Yan
• Dai Jing
• Veda Santosh Sambamoorthy
• Tan Zhenyu

Classifications

• H02J2103/30

  Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks · CPC title

• G06F30/367

  Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods · CPC title

• H02J3/008

  Circuit arrangements for power supply or distribution technologies responsive to energy trading · CPC title

• Y04S50/10

  Energy trading, including energy flowing from end-user application to grid · CPC title

• G05B19/406 Primary

  characterised by monitoring or safety (G05B19/19 takes precedence) · CPC title