The Application of UPS Power Supply in Expressway Power Supply System

Abstract: This article introduces the requirements of power supply systems for highway electrical equipment, analyzes the application and problems of traditional UPS on highways, and proposes power supply solutions for highways.

Keywords: Expressway; UPS; Power supply system; Voltage regulator

With the vigorous development of domestic highways, the construction of highways has extended to various parts of the country. In remote areas, the power supply of highways has to use local agricultural power sources, resulting in large voltage fluctuations and frequent power outages, which seriously affect the normal operation of highways. This article introduces and applies the UPS power system, and elaborates on the important role of the UPS power system in the electricity consumption of highways.

1. Classification of UPS power supply forms

1.1 Overview of UPS

UPS power supply is an abbreviation for uninterruptible power supply, which has the ability to stabilize voltage, stabilize frequency, and resist harmonic interference. It can use electrical loads to provide uninterrupted power to electrical equipment, and is divided into high power, medium power, and low power based on its output power; According to its input and output forms, it can be divided into single-phase input single-phase output, three-phase input single-phase output, and three-phase input three-phase output; According to its internal working principle, it can be divided into online, online interactive, and backup.

1.2 Classification of UPS power supply forms

(1) Distributed power supply mode

This form of power supply has the advantages of easy installation and use, and low investment. If it fails, it will only lead to a power outage of the entire circuit of the machine, making some equipment unable to work, and the operation of the entire system will not be greatly affected. However, when the local power supply cannot be carried out normally, it will affect the continuity and reliability of the power supply.

(2) Centralized power supply method

This power supply method has the advantages of high power supply quality, low failure rate, high cost-effectiveness, and is not prone to unexpected power supply interruptions; However, due to its large power supply range, any faults that are difficult to eliminate during use will cause a large range of power outages, with a wide range of impacts; When the electricity load is more dispersed, it will increase the failure rate and energy consumption.

The Role of UPS in Expressway Power Supply System

In highways, the highest demand for electricity should belong to toll systems, followed by information communication systems, electronic data processing systems, substations, and road camera monitoring systems. The toll system plays an extremely important role in the operation of highways, and therefore no negligence is allowed, especially in areas with high levels of modernization. Due to the high level of automation and strict management rules and regulations on highways, for example, the cross section bars of toll stations will only be lifted after swiping the card and released to vehicles. At this point, if the card reader malfunctions due to power issues and stops working, it will cause a large number of vehicles to form blockages on the highway. According to relevant information, on a highway in Fujian, a malfunction in the "parameter regulator UPS" system caused vehicles on the highway to stop running for more than two hours, resulting in a long tail connection phenomenon of hundreds or thousands of vehicles, causing huge losses to the local economy. The relatively complete UPS power supply referenced on highways can not only achieve real-time monitoring of UPS status, battery status monitoring, input and output voltage monitoring, load change monitoring, and other monitoring data, but also easily integrate it into the network. With the widespread application of UPS in the IT industry and special precision equipment and instruments, as well as in various aspects of information collection, transmission, processing, storage, and application, its importance in highways is also increasing with the importance of information applications.

Traditional solutions for using UPS on highways

In the remote areas where the highway extends, agricultural power sources have to be used on the highway due to its location. However, due to poor power supply conditions and price differences in the surrounding environment, such as high humidity in the mountains, temperature differences caused by seasonal climate, and disturbances caused by thunderstorms. At the same time, the weak local technical strength and poor maintenance and emergency repair capabilities will all have higher requirements for UPS. For example, it is required that UPS can maintain a long service life in harsh environments. In addition, to provide the reliability of the power supply system, a first level parameter voltage regulator needs to be added to the front of the UPS to form a UPS power supply system. And different voltage regulators need to be used for different environments in different regions.

(1) Automatic voltage regulator

This type of voltage regulator has a simple structure and relatively low price, as it relies on carbon brush movement to stabilize the voltage, resulting in the output voltage meeting the load requirements to a large extent; However, there are drawbacks such as low reliability and slow dynamic response speed, which cannot isolate interference.

(2) Purification type AC voltage regulator

This type of voltage regulator forms different equivalent inductance values based on the different conduction angles of the bidirectional thyristor, ultimately resulting in a stable mode of compensating the output for changes in the input, which also replaces the original electromagnetic compensation type voltage regulator. Although this type of voltage regulator has strong reliability and anti-interference ability, its power cannot be increased, so it cannot meet the requirements of highways for voltage regulators.

(3) NPS type intelligent voltage regulator

To some extent, this type of voltage regulator belongs to a relatively high-end technology. It combines the advantages of the above two types of voltage regulators and is a patented technology product developed after technical modification. Therefore, it has excellent performance such as high input power, high efficiency, good input output isolation performance, lightweight structure, high reliability, large capacity, and can be monitored.

4. Power supply solutions in highway power supply systems

(1) Single machine power supply system

In areas with relatively stable power grid conditions on highway sections, it is recommended to minimize the addition of stabilizers in the front end of UPS, as adding one level of equipment will generate an additional fault point. Similarly, reducing the addition of avoidable equipment can to some extent avoid the occurrence of faults, thereby reducing the occurrence rate of faults.

(2) Dual machine power supply system

As a precaution, some toll stations on highways require multiple machines and systems. The so-called multi machine and multi system refers to some users requiring a UPS on each lane, so that even if one lane's power supply fails, the other lane can continue to operate as usual, thereby avoiding traffic congestion. On sections of highways that require circuit protection, two fast relays are added at both ends of the UPS to enhance the reliability of the power supply, which is both economical and easy to implement. Therefore, it is widely used in ensuring the normal operation of power supply on highways.

(3) Dual system power supply

In large power supply centers on highways, dual power supply is installed to provide dual protection for the power supply system, providing stronger reliability for uninterrupted power supply. At the same time, dual UPS redundant systems are adopted to make the two systems redundant to each other.

5 Conclusion

In summary, with the vigorous development of highway construction and the continuous improvement of highway operation and management level, the requirements for electronic and electrical equipment in the management and operation of highways are also increasing. Only the UPS uninterrupted power supply system can provide good uninterrupted current for it. Therefore, the application of UPS power supply system in highways is essential.