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| Application of German Sunlight Battery in DCS Redundant Power Supply Control System |
| Time：2019-02-12 Source：Sonnenschein Views：2583 |
Redundancy skill is often used in reliability planning of computer system, and it is one of the most useful ways to improve the reliability of computer system. In order to achieve the unity of high reliability and low power loss, we usually choose redundancy skills in the planning and application of the control system. Reasonable redundancy planning will greatly improve the reliability of the system, but together it also adds complexity and difficulty of planning, and the system using redundant equipment also adds user funding. Therefore, how to reasonably and usefully plan the redundancy of the control system is a topic worthy of discussion.
Overview of Redundant Skills
Redundant skills are the addition of surplus equipment to ensure that the system works more reliably and safely. Redundancy can be classified into component level, component level and system level according to the orientation of the system. According to the degree of redundancy, redundancy can be divided into 1:1, 1:2 and 1:n redundancy. At that time, with the continuous improvement of reliability of components, 1:1 component level thermal redundancy was a useful, relatively simple and flexible redundancy skill completion method, such as I/O card redundancy, power supply redundancy, master controller redundancy and so on. Therefore, this method is mostly used in the process control system of the mainstream at home and abroad. Of course, there are also successful examples of component-level or multiple redundancy combinations in some parts of the planning.
Purpose of redundancy planning for control system
The operation of the system is not affected by some faults, and the maintenance of faulty components has no effect on the function completion of the whole system, and can complete online maintenance, so that the faulty components can be corrected in time. Redundant planning will increase the difficulty of system planning, and redundant equipment will add the investment of user system, but this investment will change the reliability of the system. It improves the uniform fault-free time (MTBF) of the whole user system and shortens the uniform fault correction time (MTTR). Therefore, it is necessary to use the control system in important occasions.
The so-called redundant power supply, that is, standby power supply. The simplest plan is that the standby power supply is connected to the circuit power supply through a diode. Normally, the voltage of the circuit power supply is slightly higher than that of the standby voltage by subtracting the voltage drop of the diode. The diode is cut off and the standby power supply does not work. When the main power supply fails to supply normally, the standby power supply is automatically put into operation.
Tianjin Junliangcheng Power Plant started construction in 1960. The first and second phases of the project were separated from the construction of two 50MW units, which were completed and put into operation in the early 70s. The third and fourth phases of the project were separated from the construction of two 200MW units, which were put into operation in 1993. Two 50MW units in Phase II have completed heating renovation in 2004, and two 50MW units in Phase I have completed heating renovation in circulating fluidized bed in 2005. Now there are 8 units in the plant, with installed capacity of 1000MW, 200 MW heating units and 800MW pure condensation units. During this period, four 200 MW units in the third and fourth phases have been transformed into DCS control. The DCS system is based on the GD99 control system of China National Intelligence Deep, and the upper configuration software is based on the GD99 configuration software developed independently in China. The controller is based on the 534 control device of Modicon Kunteng series and I/O template.
Network Structure of DCS System
The DCS system of our factory consists of the following parts:
NPU1A and NPU1B are mutually backed-up MODICOMON manipulator data exchange servers, and it is definitely forbidden to withdraw them from operation together during the operation of the unit; NPU2A and NPU2B are mutually backed-up Longyuan patrol data exchange servers, which collect a lot of on-site monitoring data; HIS is a prehistoric station, which serves as the collection and preservation of prehistoric records and alarms; CS is a computing station, which serves as the DEH system. The network data exchange between patrol station and DCS system; OPR1-OPR6 is operator station, which is the channel for operator supervision and operation; MIS is MIS station, which acts as data communication with MIS network at factory level. They are connected to two HUBs separately through their respective dual network cards to form the actual redundant 100M star ethernet. NPU1A/1B chooses MB+network to communicate with the lower controller. The controller and I/O module are connected by coaxial cable and T-head to form the whole control system.
Network schematic diagram of DCS system
Our DCS system has five pairs of controllers: CCS controllers, EMCS controllers, SCS controllers, DAS controllers, QS soda controllers. They are separated from serving as control related equipment. All the controllers are connected to the MB + network according to the figure below, and then a complete DCS network control system is formed. As shown in Figure 1 below, this figure illustrates a CCS controller as an example.
Background of DCS Module Power Supply Reform
I/O module power supply faults Any kind of electronic device has an objective probability of faults. Our factory has happened before because of the damage of CPS card of DCS template power supply, resulting in the loss of all module power supply in the bank, all data back to zero, forming the DCS system regulation out of control, to some companies and the formation of certain economic losses and adverse effects.
Single power supply is selected with high probability of artificial misoperation. Once staff touch or misoperate the power switch of CPS power supply template, maybe the upper power supply of the power supply template loses power, the result is the same grim.
I/O Signal Template Redundancy Equipment Completion Difficulty
Primary I/O template redundant equipment is expensive, the cost pressure from the investors and DCS manufacturers is very high, and it is extremely difficult to complete the I/O template redundant equipment. Secondly, according to the system requirements and planning conventions, only redundant signals such as drum water level, furnace negative pressure and turbine speed are selected
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