The master clock is a device that can receive at least two kinds of external time reference signals at the same time. It has internal time reference and outputs time synchronization signals and time information according to the required time accuracy.

The Beidou GPS synchronous master clock means that the device receives GPS and Beidou satellite signals, and outputs other required signal formats. A typical main clock product is the SYN4505 GPS synchronous clock, which is often equipped with SYN4505A type clock from power, Smart Substation and power plant.

Type SYN4505 and SYN4505A are Xi'an R & D production and manufacture in strict accordance with the Smart Substation time synchronization system and equipment specifications, and have been widely used in power plants all over the country: Zhejiang Yueqing power plant, Haikou power plant Kai Pu test, Shanxi Pingshuo gangue power generation limited liability company, China Huadian, Hujing Xi hydropower station, Baiyin thermoelectric power plant, Chongqing Fengjie power plant and so on.

The equipment is equipped with 0CXO, receiving Beidou two generation /GPS/GLONASS satellite signals and IRIG-B code signals, generating AC and DC B code signals, pulse signals, network timing, serial port information. If some users need to input CDMA as an external reference, we can also satisfy this SYN4505 type, which can also be called Beidou GPS and CDMA master clock. The reason why CDMA is not designed as a time source is that the CDMA signal acquires time information from the local telecom base station. Compared with no GPS and Beidou satellite signal, the accuracy is considered as an option.

The SYN4505 master clock has many working modes for users to choose under different application scenarios, namely automatic mode, manual mode and time keeping mode. Next, take a power plant time synchronization system as an example to analyze the application of Beidou GPS synchronous master clock. As shown in the picture:

The power plant time synchronization system adopts a main standby architecture, 1 main clock screens (2 main clock SYN4505, each receiving both Beidou and GPS signals), and 1 extended clock screens (2 extended clock SYN4505A). The time synchronization system is composed of separate screens. The timing is mainly based on satellite timing, and the upstream IRIG-B code is time served as the standby time benchmark.

If the master clock and the extended clock are far away, IRIG-B code optical fiber transmission is needed. If it is not very far, it can be transmitted by 485. The master clock will satisfy the access of all time synchronization signal expansion devices, and the time synchronization signal expansion device will receive the time reference signals of the two main clock outputs as input, and realize the two time reference signals are mutually reserved.

The main clock screen is installed in the centralized control building. The two main clock configured by the main clock screen provides two redundant time reference models output for the whole time synchronization system. Each master clock receives both GPS signal and Beidou signal. The two main clock is interconnected by B code time reference signal, and the satellite antenna is installed on the top of the centralized control building. The extension clock screen installed in the relay room of the booster station can receive two IRIG-B code time reference signals from the two main clock of the main clock screen through the optical fiber simultaneously, and input the time reference signal of the extended clock to master and backup each other.