DC power screen selection

How to Select a Suitable DC Power Supply Screen for (Variable) Power Stations

The power operation power supply is to provide DC power supply equipment for power plants and various types of substations such as 550KV, 220KV, and 110KV, including instrumentation, relay protection, control, emergency lighting, and various types of equipment for supplying breakers and closing and secondary circuits. Low-voltage equipment uses electricity.

At present, most of the DC switching power supplies used in China's power supply use phase-controlled power supplies. However, the phase-controlled power supplies are not satisfactory in terms of ripple, efficiency, and volume, and the monitoring system is not perfect. The main and sub-stations are inconvenient for users. New requirements for power systems do not meet standards. In addition, due to the parallel operation of the charging equipment and the battery, when the ripple system is large and the float voltage is fluctuating or low, a battery pulse charging and discharging may occur, which is disadvantageous to the battery.

Since the 1990s, new power plants and substations in the United States, Germany, and other western countries have all used switching power supplies, and their batteries have also changed from their original cadmium-nickel batteries to lead-acid maintenance-free batteries due to new circuit breakers (vacuum switches or spring energy storage). With the adoption of), the closing current is greatly reduced and the double busbars are gradually replaced with single busbars.

High-frequency switching power supplies cater to the trend of modern power supplies because of their small size, light weight, high efficiency, low output ripple, module stacking, N+1 hot backup design, and ease of computer management. In the computer, aerospace, communications, instrumentation, switching power supply has been widely used. In recent years, the domestic power supply has gradually replaced the phase-controlled power supply with a switching power supply. It can be expected that, in the power operation power supply, the gradual replacement of the phase-controlled power supply by the switching power supply will become a trend.

With the increasing popularity of high-frequency switching power supplies in China's power system, more and more conventional DC power supply screens in substations (power plants) have been replaced by high-frequency switching power supplies. The original Ministry of Electric Power and the Ministry of Water Resources have also clearly defined the mode of miniaturization and unattended operation of the extension (transformation) power station. This development trend has led to numerous manufacturers in the DC power equipment market. So how do you choose the DC power screen you need? The author of the experience of many years engaged in related work, talk about the following views.

1. Whether the selected device is suitable for many people When choosing a high-frequency DC power supply device, it is often the case that the higher the technical level is, the better, and the more expensive the better, which is not the case. Any product has a process from trial production to maturity, which requires the user to feedback to the manufacturer to continuously improve the problems that occur in the actual operation, and the principle of high-frequency switching power supply is already very mature. Most manufacturers use the classic circuit. Therefore, the device you choose is best to have a stable operating experience for more than one year. On the other hand, we must consider the adaptability of the technical requirements of our own (transformed) power plants. For example, most rural (transformation) power stations in China do not have the conditions for unattended work, so there is no need to choose a fully-equipped device with four functions, such as considering possible future Networking, to achieve communication requirements, the order can be required to retain the communication interface in order to facilitate future transformation. Secondly, the battery selection is also very important. The battery is divided into anti-acid type, sealed type, and fully-sealed type. Now, the sealed type is generally selected.

2. The anti-jamming and reliability of equipment With the rapid development of science and technology, in recent years, the new results of microcomputer technology have been widely adopted in power station integrated automation devices, and its degree of automation has been greatly improved. However, the most important and fundamental requirement of the power system is the safety and reliability of the equipment. For this reason, when choosing a DC power supply device, special attention should be paid to the main measures for its immunity. If the charger and the central controller are resistant to high-frequency interference, the system's resistance to lightning strikes and the reliability of the system's grounding must all be rigorously assessed. source:

High-frequency switching power supply adopts microcomputer control, if some manufacturers use industrial control computers, some use programmable controllers, and some use single-chip microcomputers, and computer technology develops rapidly, so the situation that often arises is: on behalf of the most advanced technology production in the year. The product lacks the necessary operating time, and its reliability is a question. In general, programmable controllers are highly reliable but expensive.

3. Whether the operation and maintenance is simple and convenient When the user uses the high-frequency switching power supply to affirm its advanced performance, it should also consider whether its operation is easy to learn and whether it is convenient to maintain. Therefore, how the control software of the central controller is advanced regardless of how complex it should be Its intuitive interface, simple and convenient operation. In the event of a fault, its display automatically displays the main parameters such as the nature of the fault, the time of occurrence, and the location of the fault, and has a strong self-test function to facilitate maintenance. Therefore, when selecting the DC power supply screen, it is necessary to observe the software display of the manufacturer, and in combination with the actual conditions of its own operation and maintenance in the future, examine the operation and display of the central controller, whether it is simple and intuitive.

4. The price is reasonable and reasonable price is one of the factors that most users must consider. When many users consider the DC power supply screen, they often feel puzzled about the price difference between different manufacturers of the same type of equipment. In fact, this is caused by several reasons: First, the cost of high-frequency switching modules is different, and some manufacturers have high prices. The frequency switch module adopts imported components, and the cost of its modules is relatively high. However, some manufacturers use domestic components for their high-frequency switch modules, and their cost is low. Second, the cost of the central controller is different. Some manufacturers' central controllers use programmable logic controllers (PLCs). This is what most manufacturers use now, and the manufacturers of programmable controllers are also different. The brand price is lower and the original imported price is lower. Third, the output currents of the modules used by different factories are not the same, such as the output current of the module is small, the number of modules is large, and the reliability is high, but the cost is increased. For the above factors, the user must comprehensively consider when ordering equipment. Source: tede

5. After-sales service After-sales service has a direct impact on the user's determination to choose high-tech products, and ultimately determines the manufacturer's sales market. In this regard, some manufacturers ignored the after-sales service in the prevailing market conditions, which eventually led to a decline in the corporate image and a shrinking market. They have profound lessons. Because the high-frequency DC power supply screen is a high-tech product, users, especially users with relatively poor technical level, have made certain risks when they make this choice for the first time. If the manufacturers do not provide after-sales service, there is a worry for users. , it will inevitably affect its enthusiasm, and ultimately affect the promotion and application of products. There are many internal information exchanges in the power system. When users select a model, they can first understand the usage and opinions of the manufacturer's users as a reference for selecting a manufacturer.

DC screen product selection table