Method and apparatus for real time recursive parameter energy management system

• US 5,708,590 A
• Filed: 12/05/1996
• Issued: 01/13/1998
• Est. Priority Date: 04/17/1995
• Status: Expired due to Term

• Current Assignee: Siemens Industry Incorporated (Siemens AG)
• Original Assignee: Siemens Energy & Automation Incorporated (Siemens AG)
• Inventors: Mokhtari, Sasan, Slutsker, Ilya, Clements, Kevin
• Primary Examiner(s): Trammell, James P.
• Assistant Examiner(s): SMITH-STEWART, DEMETRA R
• Application Number:
  US08/761,033
• Time in Patent Office: 404 Days
• Field of Search: 364/492, 364/481, 364/483, 364/495, 364/572, 364/578, 364/550, 307/59, 307/62, 307/38, 307/39, 307/40, 307/41
• US Class Current: 700/286
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: H02J 3/24 Arrangements for preventing or reducing oscillations of power in networks by control effected upon a single generator H02P9/00

Abstract

A new method and apparatus for recursive parameter estimation which closely approximates actual values is taught. Briefly stated, the within invention estimates impedance parameters of network branches in both on-line and off-line modes, providing accurate estimation of branch parameters in the presence of noise in measurements and rejecting gross measurement errors, by use of a Kalman type Markov filter scheme using maximum likelihood estimation.

Claims

1. An energy management system for recursive parameter energy management control, comprising:

control means for changing the settings of a power grid or subsystem (grid);

measurement means for measuring the status and settings of said (grid) and producing representative grid data thereof;

a computer having memory means for storing said grid data and further having a program means for analyzing said grid data and producing values representative of the impedance parameters of said grid, said program means including means for separating said grid data into a plurality of sub-grid data sets, each of said sub-grid data sets containing a predetermined number of unknown grid impedance parameters and means for recursively modeling each of said sub-grid data sets into Markov processes; and

comparing the impedance parameters of said grid which were derived from Markov processes recursively modeling said sub-grid data sets a predetermined grid impedance parameters.

2. An energy management system according to claim 1 wherein said control means changes said settings of said grid in response to said comparison of said derived impedance parameters with said predetermined grid impedance parameters.

3. An energy management system according to claim 1 wherein said grid data is comprised of at least voltage magnitudes and angles and wherein said program means treats said voltage magnitudes and angles as noncorrelated in time where X(t_i +1) does not depend on X(t_i).

4. An energy management system according to claim 3 wherein the model for X is such that it is a discrete time white noise random process obeying the difference equation:

space="preserve" listing-type="equation">X(t.sub.i -1)=X(t.sub.i)+ω

(t.sub.i)

where ω

(t_i) is discrete time gaussian white noise.

5. An energy management system according to claim 1 wherein unknown grid impedance parameters are modeled to said Markov processes according to:

space="preserve" listing-type="equation">P(t.sub.i +1)=P(t.sub.i)+ν

(t.sub.i)

where ν

(ti) is discrete time gaussian white noise.