Application of the hottest power module in distrib

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The application of power module in distribution automation

distribution automation uses modern electronic technology, communication technology, computer and network technology to integrate real-time distribution information, offline information, user information, electrical structure parameters and geographic information to form a complete automatic management system to realize the normal operation of distribution system and the monitoring, protection, control and distribution management in case of accidents. (1) The development of distribution automation is inseparable from the cooperation and coordination of various industries. In order to help the development of distribution automation, jinshengyang Technology Co., Ltd. has specially launched a special power supply with high reliability, providing reliable and efficient power solutions

keyword: configuration automation; Charging power supply; Jin Shengyang; EMC; Reliability; Power distribution terminal

1. Introduction

the National Energy Administration released the action plan for power distribution construction and transformation (2015-2020), which clearly mentioned that by 2020, the intelligent construction and application level of central cities (districts) will be greatly improved, the power supply reliability will reach 99.99%, the average annual power outage time of users will not exceed 1 hour, and the power supply quality will reach the international advanced level. In, the investment in power distribution construction and transformation was no less than 2trillion yuan. (2)

at present, the average outage time of power users in China is 400 minutes, while that in developed countries is less than 100 minutes. There is still much room for efforts between the reliability and power supply quality of China's power distribution and the international advanced level (see Figure 1). What are the factors that affect the reliability and power supply quality of distribution automation in China? From a technical point of view, there are no more than two reasons: the reliability of hardware equipment, software configuration information and data processing management mode

Figure 1 average outage time of power users in various countries (minutes)

2 The composition of the system and its main functions are shown in Figure 2 below. From the perspective of design, the main station layer, sub station layer and communication layer prefer the software part of data information. The equipment in this part is generally used as the carrier of data information, and the working environment of the equipment is relatively good; The terminal layer is a part of hardware equipment, which is directly connected with electricity. It is mostly placed outdoors, and the power supply and working environment are very poor. The terminal is electrically connected and needs to withstand electrical fluctuations and interference; The terminal is connected to the switch gate. At the moment of opening and closing, the voltage disturbance is very large, and even the power supply voltage of the switch gate will be pulled down

Figure 2 composition block diagram of distribution automation system (the picture comes from the network)

the power industry standard to promote the transformation and upgrading of traditional industries dl/t721 issued by the National Energy Administration in 2013 clearly points out that when the power circuit voltage is greater than 60V, 5kV universal energy test machine voltage should be applied. At the same time, the terminal needs to have good EMC anti-interference ability. EMC immunity level shall reach level 4 (the highest level), and the terminal equipment is required to work normally, and its performance index shall meet the requirements of basic performance. The main requirements of EMC are shown in Table 1

in order to adapt to the application of distribution automation, the front-end AC-DC power supply of the terminal needs to have the same anti-interference ability, and provide main EMC protection for the back-end control board and acquisition board. It is really the first to bear the brunt. There is a long way to go

Table 1 EMC requirements for automatic remote terminal

3 Recommended application scheme of power supply in distribution automation

in distribution terminals, DTU and FTU terminal units are usually equipped with switch gate actuators, as shown in Figure 4. Therefore, the transient output power must be considered. The mbpa27d27 charging power supply of jinshengyang is designed for such applications, which can provide up to 1080W (300ms) of transient output power to ensure that the switching gate actuator acts according to the specified instructions, and the voltage disturbance is very small, so it will not affect the work of other circuits because of the action of the switching gate actuator

it can be seen from Figure 3 that if the power response speed is not fast enough and cannot be adjusted in time, voltage drop will occur

Fig. 3 Comparison between large voltage disturbance (left figure) and small voltage disturbance (right figure) when opening and closing the gate

yellow: output voltage waveform. Blue: waveform of gate opening and closing starting current

figure 4dut/ftu power distribution terminal power block diagram

recommendation for selection of jinshengyang distribution automation power supply solution:

usually, MCU circuits and their peripheral circuits need to be isolated from the charging power supply to reduce the impact of high-frequency interference on MCU circuits. Here, it is recommended that 3000V isolated ultra wide voltage input regulated power supply urf2405lp-20wr3 take power from the output end of the charging power supply to provide stable 5V voltage for MCU and its peripheral circuits, and can solve the interference of common mode surge to MCU

it is recommended that urf2424p-6wr3 wide voltage input DC-DC power supply of remote signaling unit be isolated to avoid common mode surge impacting the system from the remote signaling port. If the impact is light, the system will crash and restart, and if it is serious, the system will be damaged

when the positive and negative power supply is required to power the operational amplifier, a0512d-2wr2 constant voltage input DC-DC power supply can be selected to provide ± 12V voltage output. For 485 communication, td501d485h can be selected for isolation to avoid interference of communication port affecting system reliability

5. Displacement resolution: 0.01mm

analysis of design points of automatic system: select high isolation power module and carry out bypass treatment

due to the harsh EMC environment faced by the terminal, the system has many local grounding, and common mode interference has a great impact on the system. For the application of power supply, first of all, we should try to use high isolation power modules (such as 3000V isolation URF series modules provided by Jin Shengyang) or bypass the sensitive ports (such as adding 1NF capacitor bypass on the reset port of single chip microcomputer) to solve the impact of common mode interference such as common mode surge/pulse group on the system, Professor gangarao introduced that the system crashed or was heavy: "Even if the joint crack starts under the overload state, it should be bypassed at the sensitive signal input and output port.

then, how to bypass the sensitive port? Here is a simple but very classic case. As shown in Figure 5: when working normally, design according to the left figure, and the circuit can run according to the predetermined program. When testing the performance of 4KV pulse group, it is easy to see that the triode is not affected Control and malfunction. The phenomena shown in the system are relay jumping by mistake, some indicator lights or some devices flashing and jumping, etc. In fact, when the i/o port is long or the control circuit is large, it is easy to couple high-frequency signals, resulting in malfunction. Adding bypass capacitors can reduce the coupling of high-frequency signals, reduce the interference to ports, and improve the consistency and reliability of products. Of course, this is only a solution, which can be solved by optimizing the layout and other methods

Figure 5 Schematic diagram of typical port processing case

emc testing mostly belongs to high-frequency interference, which is easy to directly interfere with the power consumption circuit at the back end through the parasitic parameters of the ground wire and devices. Therefore, pulse groups affect the relay malfunction, common mode surge causes system restart and other phenomena often occur. Only proper power supply selection and high-quality system design can substantially improve the reliability of distribution terminals

4. Summary

in the harsh EMC and power consumption environment, to ensure the reliability of distribution automation and improve the power quality of users, the power reliability requirements of distribution terminals are extremely high, such as EMC requirements, output transient power requirements, etc. Of course, this is also inseparable from the design of the system. It is far from enough to rely solely on the power supply to improve the reliability. Jin Shengyang is not only providing high reliable power supply solutions for distribution automation, but also constantly exploring the technology to improve the reliability of power supply, so as to help the development of distribution automation

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