Home > matpower6.0 > cpf_detect_events.m

cpf_detect_events

PURPOSE ^

CPF_DETECT_EVENTS Detect events from event function values

SYNOPSIS ^

function [rollback, evnts, cef] = cpf_detect_events(cpf_events, cef, pef, step, verbose)

DESCRIPTION ^

CPF_DETECT_EVENTS  Detect events from event function values
   [ROLLBACK, CRITICAL_EVENTS, CEF] = CPF_DETECT_EVENTS(CPF_EVENTS, CEF, PEF, STEP, VERBOSE)
   
   Inputs:
       CPF_EVENTS : struct containing info about registered CPF event fcns
       CEF : cell array of Current Event Function values
       PEF : cell array of Previous Event Function values
       STEP : current step size
       VERBOSE : 0 = no output, otherwise level of verbose output

   Outputs:
       ROLLBACK : flag indicating whether any event has requested a
           rollback step
       CRITICAL_EVENTS : struct array containing information about any
           detected events, with fields:
           eidx        : event index, in list of registered events
                           0 if no event detected
           name        : name of event function, empty if none detected
           zero        : 1 if zero has been detected, 0 otherwise
                           (interval detected or no event detected)
           idx         : index(es) of critical elements in event function
           step_scale  : linearly interpolated estimate of scaling factor
                         for current step size required to reach event zero
           log         : 1 log the event in the results, 0 don't log the event
                         (set to 1 for zero events, 0 otherwise, can be
                           modified by callbacks)
           msg         : event message, set to something generic like
                           'ZERO detected for TARGET_LAM event' or
                           'INTERVAL detected for QLIM(3) event', but intended
                         to be changed updated to callbacks
       CEF : cell array of Current Event Function values

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function [rollback, evnts, cef] = cpf_detect_events(cpf_events, cef, pef, step, verbose)
0002 %CPF_DETECT_EVENTS  Detect events from event function values
0003 %   [ROLLBACK, CRITICAL_EVENTS, CEF] = CPF_DETECT_EVENTS(CPF_EVENTS, CEF, PEF, STEP, VERBOSE)
0004 %
0005 %   Inputs:
0006 %       CPF_EVENTS : struct containing info about registered CPF event fcns
0007 %       CEF : cell array of Current Event Function values
0008 %       PEF : cell array of Previous Event Function values
0009 %       STEP : current step size
0010 %       VERBOSE : 0 = no output, otherwise level of verbose output
0011 %
0012 %   Outputs:
0013 %       ROLLBACK : flag indicating whether any event has requested a
0014 %           rollback step
0015 %       CRITICAL_EVENTS : struct array containing information about any
0016 %           detected events, with fields:
0017 %           eidx        : event index, in list of registered events
0018 %                           0 if no event detected
0019 %           name        : name of event function, empty if none detected
0020 %           zero        : 1 if zero has been detected, 0 otherwise
0021 %                           (interval detected or no event detected)
0022 %           idx         : index(es) of critical elements in event function
0023 %           step_scale  : linearly interpolated estimate of scaling factor
0024 %                         for current step size required to reach event zero
0025 %           log         : 1 log the event in the results, 0 don't log the event
0026 %                         (set to 1 for zero events, 0 otherwise, can be
0027 %                           modified by callbacks)
0028 %           msg         : event message, set to something generic like
0029 %                           'ZERO detected for TARGET_LAM event' or
0030 %                           'INTERVAL detected for QLIM(3) event', but intended
0031 %                         to be changed updated to callbacks
0032 %       CEF : cell array of Current Event Function values
0033 
0034 %   MATPOWER
0035 %   Copyright (c) 2016, Power Systems Engineering Research Center (PSERC)
0036 %   by Ray Zimmerman, PSERC Cornell
0037 %   and Shrirang Abhyankar, Argonne National Laboratory
0038 %
0039 %   This file is part of MATPOWER.
0040 %   Covered by the 3-clause BSD License (see LICENSE file for details).
0041 %   See http://www.pserc.cornell.edu/matpower/ for more info.
0042 
0043 %% initialize result variables
0044 rollback = 0;
0045 evnts = struct( ...
0046     'eidx', 0, ...
0047     'name', '', ...
0048     'zero', 0, ...
0049     'idx', 0, ...
0050     'step_scale', 1, ...
0051     'log', 0, ...
0052     'msg', '' ...
0053 );
0054 
0055 %% other initialization
0056 i = 1;              %% index into evnts struct
0057 nef = length(cef);  %% number of event functions
0058 
0059 %% detect events, first look for event intervals for events requesting rollback
0060 for eidx = 1:nef
0061     if ~cpf_events(eidx).locate %% if event doesn't request rollback to locate zero
0062         continue;               %%   skip to next event
0063     end
0064 
0065     %% current and previous event function signs
0066     c_sign = sign(cef{eidx});
0067     p_sign = sign(pef{eidx});
0068 
0069     %% if there's been a sign change and we aren't within event tolerance ...
0070     idx = find( abs(c_sign) == 1 & c_sign == -p_sign & ...
0071                 abs(cef{eidx}) > cpf_events(eidx).tol  );
0072     if ~isempty(idx)
0073         if step == 0    %% if it's a "repeat" step (e.g. after bus type changes)
0074             %% ... make this one the critical one and call it a ZERO event
0075             evnts.eidx = eidx;
0076             evnts.name = cpf_events(eidx).name;
0077             evnts.zero = 1;
0078             evnts.idx = idx;
0079             evnts.step_scale = 1;
0080             evnts.log = 1;
0081             evnts.msg = 'ZERO (BIFURCATION)';
0082             i = i + 1;
0083             break;
0084         else
0085             %% ... compute step size scaling factors and find index of smallest one
0086             [step_scale, j] = ...
0087                 min(pef{eidx}(idx) ./ (pef{eidx}(idx) - cef{eidx}(idx)) );
0088 
0089             %% if it's smaller than the current critical one ...
0090             if step_scale < evnts.step_scale
0091                 %% ... make this one the critical one
0092                 evnts.eidx = eidx;
0093                 evnts.name = cpf_events(eidx).name;
0094                 evnts.zero = 0;
0095                 evnts.idx = idx(j);
0096                 evnts.step_scale = step_scale;
0097                 evnts.log = 0;
0098                 evnts.msg = 'INTERVAL';
0099                 rollback = 1;   %% signal that a rollback event has been detected
0100             end
0101         end
0102     end
0103 end
0104 
0105 %% if no rollback events were detected
0106 if rollback == 0
0107     %% search for event zeros
0108     for eidx = 1:nef
0109         %% if there's an event zero ...
0110         idx = find( abs(cef{eidx}) <= cpf_events(eidx).tol );
0111         if ~isempty(idx)
0112             %% set event function to exactly zero
0113             %% (to prevent possible INTERVAL detection again on next step)
0114             cef{eidx}(idx) = 0;
0115 
0116             %% ... make this one the critical one
0117             evnts(i).eidx = eidx;
0118             evnts(i).name = cpf_events(eidx).name;
0119             evnts(i).zero = 1;
0120             evnts(i).idx = idx;
0121             evnts(i).step_scale = 1;
0122             evnts(i).log = 1;
0123             evnts(i).msg = 'ZERO';
0124             i = i + 1;
0125         end
0126     end
0127     
0128     %% and if no zeros were detected
0129     if i == 1
0130         %% search for intervals for non-rollback events
0131         for eidx = 1:nef
0132             %% current and previous event function signs
0133             c_sign = sign(cef{eidx});
0134             p_sign = sign(pef{eidx});
0135 
0136             %% if there's been a sign change ...
0137             idx = find( abs(c_sign) == 1 & c_sign == -p_sign );
0138             if ~isempty(idx)
0139                 %% ... compute step size scaling factors ...
0140                 step_scale = pef{eidx}(idx) ./ (pef{eidx}(idx) - cef{eidx}(idx));
0141 
0142                 %% ... and save the info as an interval detection
0143                 evnts(i).eidx = eidx;
0144                 evnts(i).name = cpf_events(eidx).name;
0145                 evnts(i).zero = 0;
0146                 evnts(i).idx = idx;
0147                 evnts(i).step_scale = step_scale;
0148                 evnts(i).log = 0;
0149                 evnts(i).msg = 'INTERVAL';
0150                 i = i + 1;
0151             end
0152         end
0153     end
0154 end
0155 
0156 %% update msgs
0157 if evnts(1).eidx
0158     for i = 1:length(evnts)
0159         if length(cef{evnts(i).eidx}) > 1
0160             s1 = sprintf('(%d)', evnts(i).idx);
0161         else
0162             s1 = '';
0163         end
0164         if rollback
0165             s2 = sprintf('ROLLBACK by %g', evnts(i).step_scale);
0166         else
0167             s2 = 'CONTINUE';
0168         end
0169         evnts(i).msg = sprintf('%s detected for %s%s event : %s', ...
0170             evnts(i).msg, evnts(i).name, s1, s2);
0171     end
0172 end

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