Systems, apparatus and methods for quantifying and identifying diversion of electrical energy

• US 9,418,045 B2
• Filed: 11/19/2012
• Issued: 08/16/2016
• Est. Priority Date: 12/12/2011
• Status: Active Grant

• Current Assignee: MBH Consulting Ltd.
• Original Assignee: MBH Consulting Ltd.
• Inventors: Hughes, Michael Brent
• Primary Examiner(s): Toatley, Jr., Gregory J
• Assistant Examiner(s): Stifter, Jr., Terence
• Application Number:
  US13/681,321
• Publication Number:
  US 20130151177A1
• Time in Patent Office: 1,366 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/28 Supervision thereof, e.g. detecting power-supply failure by out of limits supervision
• CPC Class Codes: G06F 17/10 Complex mathematical operations function generation by table look-up G06F1/03; evaluation of elementary functions by calculation G06F7/544
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: G06Q 10/063 Operations research, analysis or management
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: Y04S 50/16 Energy services, e.g. dispersed generation or demand or load or energy savings aggregation

Abstract

Systems, apparatus and methods for quantifying and identifying diversion of electrical energy are provided. Bypass and tap diversions may be identified in an electric utility power distribution inventory zone having both bypass and tap diversions. Bypass diversion factors for consumer nodes in an inventory zone are determined by finding a solution to a system of load balance equations having slack variables representing aggregate tap loads for the inventory zone and in which consumer load profile data is scaled by the bypass diversion factors, which solution minimizes an objective function whose value is positively related to the sum of the slack variables representing the aggregate tap loads. Tap loads are correlated with nodes in an inventory zone by solving a first system of power flow equations not having variables representing tap loads, and then solving a second system of power flow equations having variables representing tap loads using an iterative numerical solution technique initialized based on the solution to the first system of power flow equations.

Claims

1. A method for identifying tap loads in an electric utility power distribution inventor zone, the inventory zone comprising a plurality of nodes including a metered distribution node and at least two metered consumer nodes, the method comprising:

obtaining an admittance matrix modeling the electrical admittance between the nodes of the inventory zone;

obtaining substantially instantaneous real and reactive load data for each of the metered nodes of the inventory zone, wherein the substantially instantaneous real and reactive load data are acquired substantially simultaneously;

obtaining substantially instantaneous voltage magnitude data for each of the metered nodes of the inventory zone, wherein the sustantially instantaneous voltage magnitude data are acquired substantially simultaneously;

determining a voltage phase angle for each of the consumer nodes that solve a first system of power flow equations for the inventory zone having known values corresponding to the real and reactive load data for the consumer nodes and in which the distribution node is treated as a slack node;

determining real and reactive unmetered tap loads corresponding to select ones of the consumer nodes that;

solve a second system of power flow equations for the inventory zone having known values corresponding to the real and reactive load data for each of the nodes, voltage magnitude values corresponding to the voltage data for each of the metered nodes, and having slack variables representing the real and reactive unmetered tap loads,

and

minimize an objective function whose value is positively related to at least one of the slack variables representing the real and reactive unmetered tap loads using an iterative numerical solution technique wherein variables in the second system of power flow equations corresponding to the voltage phase angles of the select ones of the consumer nodes are initialized to values corresponding to the corresponding determined voltage phase angles that solve the first system of power flow equations; and

,

cutting power to consumer nodes corresponding to the determined real and reactive unmetered tap loads.

2. The method of claim 1 wherein the select ones of the consumer nodes comprise all of the consumer nodes in the inventory zone.

3. The method of claim 1 wherein at least one of the consumer nodes in the inventory zone is not one of the select ones of the consumer nodes.

4. The method of claim 1 wherein in the first system of power flow equations variables corresponding to the voltage magnitudes of the consumer nodes are initialized to values corresponding to the instantaneous voltage magnitude data obtained for the distribution node.

5. The method of claim 4 wherein in the first system of power flow equations a term corresponding to a voltage magnitude of the distribution node is fixed to equal a value corresponding to the instantaneous voltage magnitude data obtained for the distribution node.

6. The method of claim 5 wherein in the first system of power flow equations a term corresponding to a voltage phase angle of the distribution node is fixed to equal zero.

7. The method of claim 6 wherein in the second system of power flow equations a term corresponding to a voltage phase angle of the distribution node is fixed to equal zero.

8. The method of claim 1 wherein in the second system of power flow equations variables corresponding to the real and reactive unmetered tap loads of a consumer node are further constrained by a pre-determined relationship with one another.

9. The method of claim 8 wherein the pre-determined relationship comprises a linear relationship.

10. The method of claim 8 wherein the pre-determined relationship specifies that the reactive tap load is equal to the product of the real tap load and a scale factor.

11. The method of claim 10 wherein the scale factor is less than or equal to 0.2.

12. The method of claim 10 comprising determining the scale factor by:

determining a real component of aggregate tap power based on a difference between a real power value for the distribution node that solves the first system of power flow equations and a real power value for the distribution node corresponding to the obtained substantially instantaneous real load data for the distribution node;

determining a reactive component of aggregate tap power based on a difference between a reactive power value for the distribution node that solves the first system of power flow equations and a reactive power value for the distribution node corresponding to the obtained substantially instantaneous reactive load data for the distribution node; and

determining the scale factor as an aggregate tap power factor based on the real and reactive components of aggregate tap power.

13. The method of claim 1 wherein the inventory zone comprises one or more unmetered nodes, and wherein in the first system of power flow equations voltage magnitude and phase angles for the unmetered nodes are treated as unknowns and wherein real and reactive power for the unmetered nodes are fixed to arbitrary values.

14. The method of claim 13 wherein in the second system of power flow equations voltage magnitude and tap affected phase angles for the unmetered nodes are treated as unknowns.

15. The method of claim 1 wherein the inventory zone comprises two or more secondary distribution nodes to which metered consumer nodes are connected, comprising, when the iterative numerical solution technique fails to converge:

for each secondary distribution node;

determining calculated complex consumer voltages and real and reactive secondary unmetered tap loads corresponding to that secondary node that solve a third system of power flow equations for the inventory zone which allow for a secondary tap at that secondary distribution node having fixed values corresponding to the real and reactive unmetered tap loads determined for the consumer nodes, and having slack variables representing calculated consumer voltages and real and reactive secondary unmetered tap loads, and minimize an objective function whose value is positively related to at least one of the slack variables representing the calculated consumer voltages and real and reactive secondary unmetered tap loads using an iterative numerical solution technique; and

,

when the iterative numerical solution technique converges to a solution, storing calculated voltage magnitudes corresponding to the calculated complex consumer voltages in a data structure indexed by secondary distribution node,

determining a voltage difference between each of the voltage magnitudes corresponding to the calculated complex consumer voltages stored in the data structure indexed by secondary distribution node and the voltage magnitude values corresponding to the voltage data for each of the metered consumer nodes;

identifying each voltage difference which exceeds a rated measurement error of the corresponding meter as a voltage violation;

determining a voltage difference range for each secondary distribution node having voltage magnitudes corresponding to the calculated complex consumer voltages stored in the data structure; and

determining a secondary tap location based on the voltage difference range and number voltage violations for each secondary distribution node.

16. The method of claim 15 wherein determining the secondary tap location comprises identifying the secondary distribution node whose voltage difference is less than twice the rated measurement error and having the fewest voltage violations as the secondary tap location.

17. The method of claim 16 wherein determining the secondary tap location comprises identifying two secondary distribution nodes whose voltage differences are less than twice the rated measurement error and having relatively low numbers of voltage violations, and determining the secondary tap location to be between the identified two secondary distribution nodes.

18. The method of claim 17 comprising determining a cumulative voltage difference for each of the identified two secondary distribution nodes and further narrowing the secondary tap location based on a relation between the cumulative voltage differences.

19. The method of claim 1 wherein obtaining the substantially instantaneous real and reactive load data for the consumer nodes comprises obtaining at least one measurement corresponding to one of the consumer nodes and multiplying the measurement by a bypass diversion factor corresponding to that consumer node.

20. A system for identifying tap loads in an electric utility power distribution inventory zone, the inventory zone comprising a plurality of nodes including at least one metered distribution node and at least two metered consumer nodes, the system comprising:

a data store comprising a non-transitory computer readable medium of the data store contains an admittance matrix modeling the electrical admittance between the nodes of the inventory zone, substantially instantaneous real and reactive load data for each of the metered nodes of the inventory zone, wherein the substantially instantaneous real and reactive load data are acquired subtantially simultaneously, and substantially instantaneous voltage magnitude data for each of the metered nodes of the inventory zone, wherein the substantially instantaneous voltage magnitude data are acquired substantially simultaneously; and

a data processor communicatively coupled to the data store and configured to;

obtain the admittance matrix from the data store;

obtain the substantially instantaneous real and reactive load data from the data store;

obtain the substantially instantaneous voltage magnitude data from the data store;

determine a voltage phase angle for each of the consumer nodes that solve a first system of power flow equations for the inventory zone having known values corresponding to the real and reactive load data for the consumer nodes and in which the distribution node is treated as a slack node;

determine real and reactive unmetered tap loads corresponding to select ones of the consumer nodes that;

solve a second system of power flow equations for the inventory zone having known values corresponding to the real and reactive load data for each of the nodes, voltage magnitude values corresponding to the voltage data for each of the metered nodes, and having slack variables representing the real and reactive unmetered tap loads, and

minimize an objective function whose value is positively related to at least one of the slack variables representing the real and reactive tap loads

using an iterative numerical solution technique wherein variables in the second system of power flow equations corresponding to the voltage phase angles of the select ones of the consumer nodes are initialized to values corresponding to the corresponding determined voltage phase angles that solve the first system of power flow equations; and

cut power to consumer nodes corresponding to the determined real and reactive unmetered tap loads.