GPS Beidou clock system used in substation II

GPS Beidou clock system used in substation II

3 GPS Beidou clock system installation and maintenance

3.1 Substation GPS Beidou clock system configuration

The substation GPS Beidou clock system consists of a standard time synchronization clock body and a time signal expansion device.

Taking a 500kV substation as an example, this station adopts the K800 type GPS Beidou clock system produced by Shanghai Ruicheng to achieve unified alignment with various secondary systems of the entire station. The main clock cabinet is located in the 220kV#2 booth, and an expansion clock cabinet is set in the 220kV#2 booth and other small protection rooms. The main clock cabinet has two kinds of time synchronization system input, that is, the GPS master clock and the Beidou master clock are used as backups. The master clock cabinet is responsible for receiving GPS and Beidou antenna clocks and sending GPS and Beidou antenna clock signals to each extension through two optical cables. Clock cabinets, each extended clock through the output interface module will send the clock signal to the station within the different monitoring and control, protection, recording wave, PMU and other secondary equipment. Any system expansion clock problem does not affect the other chambers, so the system reliability is higher in this way.

3.2 GPS Beidou Clock System Installation Notes

The GPS Beidou clock system is relatively simple in terms of relative protection devices. The installation process focuses on the antenna installation process, the specification of various types of cables, and the commissioning of devices.

3.2.1 Antenna Installation

The antenna is a GPS Beidou receiver. Its installation process will affect the correctness of the GPS Beidou clock system time, and various measures must be taken to achieve the completeness and correctness of the GPS Beidou clock system antenna receiving signal: the antenna must ensure that there is enough field of vision to receive GPS The location of the signal should be in an area where it is 45 degrees away from the horizontal line. It should not be installed in the substation and out of the busbar to reduce the impact of strong magnetoelectricity on the antenna satellite reception; the distance between the antenna and the roof should not exceed Correctly install the necessary height and minimize the risk of lightning strikes. Use bare sponges, foams, and other soft objects on exposed parts of the transmission line of the antenna that may cause corrosion and rubbing against the wall. When the antenna is being cast, pay attention to The BNC connector of the antenna connection device is reliably wrapped with plastic tape and insulating tape to avoid damage during the placement process, affecting the effect of antenna star collection, and the BNC connector must be equipped with lightning protection device to prevent thunder and lightning, GPS Beidou clock system antenna The transmission line can not be bent, as far as possible arc discharge, transmission line payoff in the main control room When a cable layer, use it to hold the tie, the transmission line reaches the backward people cubicle discharge trough, is fixed in place within the required tie slot.

3.2.2 Sorting and Labeling of Various Cables

The cables in the GPS Beidou screen cabinet mainly include power cables, device signal cables to public measurement and control cabinets, GPS Beidou clock system signal output cables, and contact optical cables between the main clock cabinet and the expansion clock cabinet. To facilitate future maintenance, it must be Various types of cables are regulated and marked.

All types of cables and optical cables should be arranged neatly, should not be crossed, and fixed in time. All cables and optical cables can be listed according to the cable tag specification, that is, the cable number, cable type, starting point, and end point can be marked.

In order to facilitate the maintenance of the fiber channel in the future, the optical fiber cable should be marked from left to right according to the order of the terminal box. The order of the pigtails should also be arranged from left to right. When the cable is completed, the corresponding label paper should be affixed immediately. The device jumper and fiber pigtail fiber correspond one by one. Generally, the first two pigtails of each optical fiber cable are used as working pigtails, and the latter two are used as backups.

3.2_3GPS BeiDou clock system power on commissioning

After the GPS Beidou clock system is powered on, first check whether the main clock screen receives the satellites correctly, and then check whether the signal output in the screen is correct. Finally, check whether the timing signal of the protection room needs to be correct.

When detecting the output of the GPS device, it is necessary to first test the output level of each terminal signal with the DC voltage range of the multimeter. If the level output has no voltage, it is determined that the output is a passive pulse. The passive pulse can be directly observed by a self-made pulse signal lamp, and the normal display is a second flash. The pulse signal tester can only test the passive pulse and cannot test other signals. , so as not to cause damage to the device. The active pulse and its B code can use the multimeter's DC voltage file to check the signal. If the voltage changes once every second: The active pulse is measured by the multimeter's DC file as a voltage change every second. For example, 24V active pulse voltage will be from 24V per second. Bounce; B code signal level with the multimeter DC gear measurement constantly changes between -0.5V to +2.0V. The serial port is first tested with a DC file to see if the voltage is normal, RS232 voltage is about 9V, RS4S5 voltage is about 4V; after the voltage is normal, it can be connected to the notebook through the serial port cable, and the serial port GPS device uses the 3 and 5 pins of the serial port. The receiving device (notebook or other time-consuming device) is the pin 2 and 5 of the serial port. The serial debugging assistant is used to test whether the message output is normal. If the GPS device signal output is correct and the protection device is still not successful, you can check whether the protection device's timing mode is correct, and whether the protection device needs to add an external timing module.

3. 3 GPS Beidou Clock System Maintenance FAQ

According to statistics on the occurrence of GPS Beidou clock system in recent years, there are generally several categories:

(1) Poor contact: Poor contact of the power cord leads to abnormal operation of the GPS Beidou clock system or poor contact of the GPS output signal line, resulting in inaccurate timing of the device;

(2) Antenna failure: The exposed part of the antenna is bitten or corroded, the GPS master clock panel does not display the number of satellites received, the GPS device antenna out-of-step alarm, and the monitoring background reports GPS anomaly;

(3) Unstable signal: Signal attenuation occurs after 1-2 years of poor fusion of optical fiber splices or poor antenna operation, all of which can cause such phenomena;

(4) Aging: The GPS Beidou clock system has been running for a long time and the local components have failed to operate.

For the first type of defects, the fastening of the secondary wiring can be restored. During the installation process, the work of tightening the screws must be done. At the same time, attention should also be paid to the wiring of the internal wiring of the wide family. The second type of defect requires the re-laying of the antenna and the prevention of turbidity and small animal bite measures on the exposed part of the antenna. The third type of defect is that during the process of pigtail welding, personnel with a high level of process are required to meet the operational requirements. The identification of the fiber channel must be standardized, which will facilitate the replacement of spare pigtails and re-welding in the future. Because manufacturers have shipped the antenna head is reliable welding, try not to cut off the antenna from the re-welding, such as the antenna is indeed a long, you can coil it can be organized, so you can avoid the bad signal caused by antenna welding attenuation The phenomenon appears. The fourth type of defect can be recovered by contacting the GPS Beidou clock system manufacturer to replace the bad module.

4 Conclusion

With the continuous development of power systems to large-capacity and large-scale networks and the continuous improvement of automation, the grid has put forward higher requirements for unified standard time. GPS Beidou clock system will become the main time-of-day mode of the power system due to its high-precision timing function, and it will also lay a solid foundation for the development of the power system.