R/create_voltage_constraints.R

In asiono/rein: Distribution Grid Reinforcement Optimization

################################################################################
#' @title         create_voltage_constraints
#' @description  creates the constraints given by the voltage
#' @param solution_space  dataframe containing possible cable and transformer types in the grid and its specifications
#' @param big_M  big M value for voltage limit optimization
#' @param allowed_voltage  allowed voltage deviatipn limit
#' @param iteration  counter for reinforcement iteration.
#' @param oltc.trigger  indication for OLTC transformator usage.
#' @param verbose  Value greater than zero to display step by step of reinforcement.
#' @return This function creates the side conditions and objective function for the optimization problem. 
#' The ouput is a list. That contains A, b and c. 
################################################################################

create_voltage_constraints <- function(solution_space, big_M, allowed_voltage, iteration, oltc.trigger, verbose = 0){
  
  #building matrix to check voltage drop in all nodes without parallel line
  matrices_voltage_no_parallel <- create_voltage_constraints_no_parallel(solution_space, big_M, allowed_voltage)

  #building matrix to check whether voltage drop reduction using parallel line is applicable
  matrices_voltage_parallel <- create_voltage_constraints_parallel(solution_space, big_M, allowed_voltage)
  
  #building matrix to check voltage drop when parallel is applied
  matrices_voltage_parallel_branch <- create_voltage_constraints_parallel_branch(solution_space, big_M, allowed_voltage)
 
  A <- rbind(matrices_voltage_no_parallel$A,matrices_voltage_parallel$A,matrices_voltage_parallel_branch$A)
  AT <- matrix(rep(solution_space$T$dU, nrow(A)), ncol = length(solution_space$T$dU), byrow = T)
  big_M_OLTC <- 0.08
  const.dir <- c(matrices_voltage_no_parallel$const.dir, matrices_voltage_parallel$const.dir,
                 matrices_voltage_parallel_branch$const.dir)
  cod <- ifelse(const.dir == '>=', 1, -1)
  
  #### check if there is OLTC
  if (any(grepl('OLTC', solution_space$T$model))) {
    #print('###building matrix for OLTC###')
    ##find which column is OLTC trafo and fill it with minus BIg M
    AT_OLTC <- matrix(0, nrow = 2*nrow(AT), ncol = nrow(solution_space$T))
    colnames(AT_OLTC) <- solution_space$T$model
    for (i in 1:nrow(solution_space$T)) {
      if (grepl('OLTC', solution_space$T$model[i])) {
        AT_OLTC[, i] <- c(rep(ifelse(cod == 1, big_M_OLTC, -big_M_OLTC),2))
      }
    }
    
    #dU correction for OLTC application
    if (oltc.trigger == T) {
      dU.factor <- 1.0 + iteration/5
      matrices_voltage_no_parallel$A <- cbind(matrices_voltage_no_parallel$A[,1:nrow(solution_space$A)]*dU.factor, 
                                              matrices_voltage_no_parallel$A[,(nrow(solution_space$A) + 1):ncol(matrices_voltage_no_parallel$A)])
      matrices_voltage_parallel$A <- cbind(matrices_voltage_parallel$A[,1:nrow(solution_space$A)]*dU.factor, 
                                           matrices_voltage_parallel$A[,(nrow(solution_space$A) + 1):ncol(matrices_voltage_parallel$A)])
      matrices_voltage_parallel_branch$A <- cbind(matrices_voltage_parallel_branch$A[,1:nrow(solution_space$A)]*dU.factor, 
                                                  matrices_voltage_parallel_branch$A[,(nrow(solution_space$A) + 1):ncol(matrices_voltage_parallel_branch$A)])
      A <- rbind(matrices_voltage_no_parallel$A,matrices_voltage_parallel$A,matrices_voltage_parallel_branch$A)
    }

    
    ##built them into big M matrix
    AT <- matrix(rep(t(AT), 2), ncol = ncol(AT) , byrow = TRUE ) + AT_OLTC
    A <- cbind(AT, matrix(rep(t(A), 2), ncol = ncol(A) , byrow = TRUE ))

    ##repeat the b matrix, it is complicated because need to check with upper (+3%) and lower voltage limit swing (-3%)
    #OLTC voltage swing allowance
    b_OLTC_swing <- 0.08
    b_diff <- b_OLTC_swing - allowed_voltage
    b_OLTC1 <- c(matrices_voltage_no_parallel$b1, matrices_voltage_no_parallel$b2, 
                 matrices_voltage_parallel$b1, matrices_voltage_parallel$b2,
                 matrices_voltage_parallel_branch$b1, matrices_voltage_parallel_branch$b2)
    b_OLTC2 <- c(matrices_voltage_no_parallel$b1 + b_diff, matrices_voltage_no_parallel$b2 - b_diff,
                 matrices_voltage_parallel$b1 + b_diff, matrices_voltage_parallel$b2 - b_diff,
                 matrices_voltage_parallel_branch$b1 + b_diff, matrices_voltage_parallel_branch$b2 - b_diff)
    b <- c(b_OLTC1, b_OLTC2) 
    
    #repeat const.dir
    const.dir <- c(cod, cod)
    const.dir <- ifelse(const.dir == 1, '>=', '<=')
    
  }else{
    A <- cbind(AT, A)
    b <- c(matrices_voltage_no_parallel$b1, matrices_voltage_no_parallel$b2, 
           matrices_voltage_parallel$b1, matrices_voltage_parallel$b2,
           matrices_voltage_parallel_branch$b1, matrices_voltage_parallel_branch$b2)
  }
  
  matrices <- list( A = A, b = b, const.dir = const.dir)
  
  return(matrices)
}