# Implementation of a Demand-Side Management Solution for South Korea's Demand Response Program
## 2 Materials and Methods
### Development of Demand-Side Management Solution (DSMS)
For this objective evaluation, the RRMSE was used as an index to specify the uniformity of the pattern of power usage. Figure 5 shows the RRMSE for the customer who wants to participate in demand response market and Equation (1) shows that RRMSE calculation [26]. In this equation, \(D\) is an investigation day, \(D(n)\) is the number of investigation days, \(T\) is a time duration of an investigation day, \(T(n)\) is number of time durations of an investigation day, \(CBL_{d,t}\) is a customer baseline load at \(t\) hour on \(d\) day, and \(Load_{d,t}\) is an electricity usage at \(t\) hour on \(d\) day. \[\sqrt{\frac{\sum_{d\in D,t\in T}\big{(}CBL_{d,t}-Load_{d,t}\big{)}^{2}}{D(n) \times T(n)}}\div\frac{\sum_{d\in D,t\in T}Load_{d,t}}{D(n)\times T(n)} \tag{1}\]  
\(D(n)\): Number of investigation days  
\(T\): Time duration of investigation day  
\(T(n)\): Number of time durations of investigation day  
\(CBL_{d,t}\): Customer baseline load at \(t\) hour on \(d\) day  
\(Load_{d,t}\): Electricity usage at \(t\) hour on \(d\) day  
The RRMSE is calculated by dividing the RMSE (root mean square error) with the average value of electricity usage data. The fluctuation between the CBL and actual electricity usage is a critical judgment criterion as a reliable DR resource. To register as a DR resource in the Korea electricity market, the RRMSE value must be less than 30%; if the value exceeds 30%, it is not allowed to join the DR market. If the RRMSE value becomes more increased, conformity of power usage pattern decreases, which makes it difficult to judge the reduction value accurately. Although the U.S. PJM  
Figure 5: Relative root mean squared error (RRMSE) for a customer. \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{2}{c}{**Energy Consumed (kWh)**} & **Selection** \\ \hline D-1 & 2048.04 & O \\ \hline D-2 & 1889.74 & X \\ \hline D-3 & 1951.56 & O \\ \hline D-4 & 2055.24 & O \\ \hline D-5 & 2042.82 & O \\ \hline CBL & Average of selection value = 2024.42 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Calculation example of the customer baseline load (CBL) (Max4/5 Method). power DR market is set at less than 20%, the Korea DR market is set to within 30% at the beginning of the system. To determine the suitability of the DR customer, the KPX enforces an annual RRMSE assessment, and then that result determines whether the DR customer can participate in the DR market for one year. This calculation is based on data from 45 weekdays from the date of verification [26]. For example, the flat line of the electricity usage graph in Figure 5 indicates 10%, that means Figure 5 is a reliable DR resource, and therefore this customer can participate in the DR market. The incentive for participating in the DR market can be classified into basic settlement and performance settlement, and the monthly basic settlement payment is as shown in Table 4. According to the reduction duration time, the actual performance-settlement payment is different under the KPX condition [27]. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Month** & **Basic Settlement Payment [KRW/kW]** & **Weekday** \\ \hline  
Total & 85,077,404 & 493 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Monthly basic settlement payment 2016–2018. To calculate the basic settlement money, Equations in (2) are applied to the integrated demand-side management solution [26]. \[ \begin{split}\text{DRBP}_{i.m}=\text{ORC}_{i.m}\times\text{BP}_{m} \times 1,000\\ \text{IBPC}_{i.m}=\frac{\text{TDRBP}_{i}}{\text{ORC}_{i.m}\times \text{MRT}}\times\sum\limits_{t}^{m}DRD_{i.t}\times 2\times DF_{i.t}\\ DRD_{i.t}=Max(RSO_{i,t}\times 0.97-DR_{i,t},\ 0)\\ \text{BPC}_{i.m}=Min(\text{DRBP}_{i.m},\ \text{IBPC}_{i.m})\\ \text{FDRBP}_{i.m}=\text{DRBP}_{i.m}-\text{BPC}_{i.m}\end{split}