1 Introduction
With the development of social economy, the rapid rise of industry has led to a significant increase in some 10KV power distribution systems. The simplicity, reliability, safety, energy efficiency and cost performance of power distribution systems are particularly important.
At present, the traditional 10KV power distribution system still adopts relay system and distributed monitoring and measurement, distributed control mode, and adopts PLC (programmable controller) system centralized control and centralized monitoring and metering mode, which is beneficial to improve the operation management automation of power distribution system. The level ensures the safety and stability of the power distribution, and can also reduce the work intensity of the operating personnel, and is safe and reliable.
2. Comparison of relay system and PLC system
PLC (Programmable Logic Controller) is a new type of industrial controller developed in recent decades. Due to its flexible programming and complete functions, it is widely used in control system, easy to use, strong anti-interference ability and high cost performance. The working life is high, and its own has the characteristics of small size, light weight, and low power consumption. The relay system has obvious shortcomings: large volume, low reliability, short working life, and difficulty in finding faults, especially since it is composed of hard-wired logic, so the wiring is complicated, and the adaptability to the change of the production process is poor, which is inconvenient to implement. Centralized control; PLC installation and field wiring is simple, you can apply its internal soft relay to simplify the complicated intermediate links of the relay system, realize the soft wiring logic system, facilitate centralized control, in addition, PLC also has self-diagnosis and fault Alarm, fault alarm type display and network communication function, easy for operation and maintenance personnel to check.
3. Application examples of centralized control, centralized monitoring and measurement in 10KV power distribution primary system
In a 10KV power distribution primary system, two 1000KVA transformers are operated in parallel. In the primary distribution system, the relay system is mainly concentrated in the total receiving cabinet and transformer distribution cabinet. The PLC system is used instead of the relay system, which can reduce the hard connection between the cabinet and the cabinet, save many relays, simplify the process and reduce System manufacturing costs, improve the reliability, safety and energy efficiency of the distribution system.
PLC is the nerve center of the whole system. All control, protection and working status indications are completed by the virtual relay inside the PLC through the soft connection with the external given switch quantity and signal. The control voltage is below the safe voltage, which can improve the safety of work, and operate away from the high pressure room, which can avoid the misoperation of the staff, and the one-stop control can improve work efficiency and reduce the labor intensity of the staff. The signal transmission of the whole system can be realized by using two field buses, and the working state and alarm indication of the PLC can facilitate the troubleshooting of the work and maintenance personnel. In addition, compared with relays, PLC has high maintenance-free and long working life.
PLC I/O allocation
In the 10KV power distribution primary system, in addition to the power-on and power-off control, there are overcurrent, undervoltage and gas protection for the transformer. We use the OMRON CAMP2AH40 point PLC as an example for I/O allocation, as shown in Table 1. The upper power-off control is the switch quantity, and the control button can be selected. The over-current, under-voltage and gas protection involve automatic detection technology, and the intelligent sensor is used to realize, which can improve the reliability of protection.
Design of centralized control and centralized monitoring and measurement of 10KV power distribution primary system
The power distribution system is the nerve center of the power supply network. The normal operation of the power distribution system is inseparable from our life support and work order, which requires it to have higher reliability; the intelligent, energy-saving, easy-to-use and convenient maintenance of the power distribution system is the need for rapid economic development; Electrical system operation and maintenance are more desirable for the safety factor of the staff, lower labor intensity and higher cost performance of the equipment. Based on the above points, we have made the following improvements to the 10KV power distribution primary system. The PLC is used to achieve centralized control of the system's total receiving cabinet and distribution cabinet, and the digital instrument is used for centralized monitoring and measurement.
After the improvement, the integrated cabinet is used as the working platform. In the duty room, the staff can control the operating state of the high pressure room, which is convenient and safe. The staff can record and monitor the monitoring instruments and measuring instruments and the working or alarm status at any time. It is convenient and timely, and it can also reduce labor intensity.
In short, the use of microcomputer PLC to realize the operation of relay protection and control system, greatly improve the automation level and reliability of the system, and at the same time facilitate the centralized control and monitoring of the system, which facilitates the information management of the system, greatly reduces the cost and improves the system. The efficiency of work has a certain promotion significance
Type-C interface has strong expansion ability, can transmit video and video signals, expand to a variety of audio and video output interface, such as HDMI, VGA, DVI interface, and even achieve 4K resolution of the extended transmission. The Type-c interface provides bidirectional power supply, which can charge the device itself or power external devices.USB HUBS has better data transmission capability and higher charging power. USBType-C went into mass production in August 2014, using the 3.1 standard. Compared with the interface of USB2.0 used in early smartphones, the transmission speed is improved a lot, and the maximum data transmission speed can reach 10Gbit/ s. And type-c supports USB-PD power supply standard, the maximum power supply can be up to 100 watts. Different from the traditional USBType-A and Type-B interfaces, the new Type-C interface is slimmed down in size to 8.3*2.5mm, which is more suitable for use in increasingly miniaturized electronic devices.
Supports positive and negative insertion. 100% of the players who use USB interface have encountered the embarrassment of "the positive plug is wrong, the negative plug is wrong, and the positive plug is right". Because USB-C IS POSITIVE AND NEGATIVE CAN be inserted, professional point is to say that the interface does not have directionality, with much more convenient. type-c charging port, support PD fast charging protocol, can be charged while using the computer, not afraid of running out of power. HDMI interface, I like HDMI to support audio and video transmission, high resolution support 4K/2K. Interface is common, LCD TV, monitor, projector are generally also some (like to connect to TV, audio and video synchronous transmission).vga interface, this is a very common interface, most of the projector, monitor have this interface, can be connected to vga line use, support 1080P resolution. Gigabit network port, although now almost everywhere there is a wireless network, but sometimes it is not enough for you, such as playing games, the network speed is slow, delay. And then he dropped the line right in the middle of his victory. So if you have a network cable and you can connect directly to the Internet, it's great to support gigabit networks.
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