[15] have proposed ZigBee-based fault current indicators because it has the characteristics of easy installation and maintenance, long battery life, and low cost. However, ZigBee has short communication distance, a complex protocol stack, and a long development period. Therefore, it is not suitable for application in overhead line fault indicators. Reference [16], as our former work, has introduced the use of LoRa and NB-IoT technologies for fault indicators. As the two most popular wireless communication technologies, LoRa is much cheaper than NB-IoT, but its quality of service, such as data transmission rate, is not as good as NB-IoT. Therefore, based on the characteristics of application scenarios, which the number of acquisition units is much more than collection units and the quality of service of collection unit is required to be better, we can combine the LoRa and NB-IoT, which is acquisition unit with LoRa and collection unit with NB-IoT to achieve better results. However, the optimal configuration of fault indicators has not been considered in [16]. In order to improve the reliability and reduce the outage time, some studies have focused on the issues of optimal number and position of fault indicators. Nevertheless, the above-mentioned literatures have only focus on the optimal number and position of fault indicators [17; 18; 19; 20] or performance of the communication network [21; 22] individually. The cyber-physical system (CPS) is a kind of more complex large-scale system that can integrate physical processes, computing resources, and communication capabilities [23]. The fault indicator based on LoRa and NB-IoT applies the IoT communication technologies to the traditional power grid, which can be categorized as a kind of CPSs. For the optimal configuration of it, we need to consider the influence of communication reliability and power-supply reliability together. As a result, the determination of the number and position of fault indicators considering communication reliability and power-supply reliability is the goal of the optimization process of fault indicator placement. The solution must achieve two conflicting goals. On the one hand, if a few fault indicators are placed in the network, the communication is unreliable, which will lead to greater power outage losses. On the other hand, if a large number of fault indicators are placed in the network, the power-supply reliability and communication reliability can be guaranteed, thus causing less power failure loss. For this reason, a balance needs to be considered in the fault indicator placement to achieve the minimum economic cost. The reasonable number and location configuration scheme of the acquisition unit and collection unit of the fault indicator on the line has become an urgent problem to be solved to maximize economic benefits on the basis of satisfying power-supply reliability and communication reliability. Therefore, in this paper, a system model considering power-supply reliability and communication reliability will be established and used to obtain the optimal placement of the fault indicators to improve reliability indices with minimum economic cost. The rest of the paper is organized as follows: In Section 2, the system model and the main working principle are introduced. In Section 3, the objective function and constraint conditions of optimization are described. In Section 4, a case study and simulation results are presented and discussed. Finally, Section 5 concludes the paper.