# Design and Application of a Distribution Network Phasor Data Concentrator
## 2 DPDC Application Requirements Analysis
### Application Requirements
The table takes GB/T 26865.2-2011 as an example. The extended protocol is based on the GB/T 26865.2-2011 protocol, adding data priority, remote control commands, etc. The method is also applicable to IEEE C37.118.2-2011, more details can be seen in the paper [3];
5. A large number of \(\upmu\)MPMUs accessed by DPDC will send phasor data at high frequency and will also send a large amount of file data and commands. To avoid affecting the real-time monitoring and active control capabilities of the entire system, DPDC should be able to efficiently process, aggregate and forward data. This requires the DPDC to have a lower processing delay [8], where the DPDC processing delay is defined as the DPDC data delay, indicating the arrival time of the last complete data message with a given timestamp and its leaving time difference from the DPDC, in the case where the data aggregation is normal. DPDC data delay should be within 3-10 ms [17];
6. Since the increases in the number of \(\upmu\)MPMUs also leads to an increase in communication traffic, which further leads to an increase in storage footprint. A more directed way to reduce flow and storage space is via data compression. To avoid any data accuracy loss and data latency increase, it is beneficial to use a suitable compression method. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Device** & **PMU** & \(\upmu\)**MPMU** & **PDC** & **DPDC** \\ \hline \multirow{3}{*}{Locations} & Substation; power plant & \begin{tabular}{c} Substation; power distribution room; transformer; feeder line; DER \\ \end{tabular} & \begin{tabular}{c} Substation; power plant \\ \end{tabular} & \begin{tabular}{c} Substation; power distribution room \\ \end{tabular} \\ \hline \multirow{3}{*}{Main Functions} & Synchronous phasor measurement & Synchronous phasor measurement; distribution terminal & Aggregate and forward data & Aggregate and forward data; power distributing substation \\ \hline \multirow{3}{*}{\begin{tabular}{c} Communication Modes \\ \end{tabular} } & Optica fiber; Twisted pair & \begin{tabular}{c} Optica fiber; twisted pair; wireless private network; power line carrier \\ \end{tabular} & \
\begin{tabular}{c} Optical fiber; twisted pair; wireless private network; power line carrier \\ \end{tabular} \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Communication Protocols \\ \end{tabular} } & GB/T 26865.2-2011; IEC/TR 61850-90-2-2016 & GB/T 26865.2-2011; extended protocol & GB/T 26865.2-2011 & GB/T 26865.2-2011 & extended protocol \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Device comparison. Based on the above analysis, it can be concluded that DPDC needs to have expanded functions and features in order to cope with various situations. It summarizes the main problems faced by DPDC and their corresponding extended functions and features, as shown in Table 2.  
This paper proposes the key performance indicators of DPDC, which are also the most basic requirements for DPDC, namely access capability, time difference tolerance, and data delay. The performance of DPDC consists of software performance and hardware performance. The hardware performance depends on the CPU, network port, running memory and hard disk. The software performance is affected by the program frame and operation mechanism. By testing the key performance indicators of DPDC, the performance of DPDC is judged [22].