First, the status quo of the manufacture of piezoelectric and switchgear equipment in the domestic manufacturing situation of medium-voltage devices and switchgears: more than five and five manufacturers of similar products; 2 similar manufacturing levels; 3 medium and low-end technical products 4; more simple products to imitate; 5 assets and technology industry strength is thinner; 1 available for power users with fewer varieties; 2 advanced processing equipment, design and manufacturing capabilities of the manufacturers less 3 篼 technology content level of products less 4 Self-developed products with stable user market 5 Assets and technology industry Strong manufacturing companies with weak market participation are weak; ability to independently develop products and improve technology; poor access to various types of information, poor capabilities and ways Less, these are the majority of the current.
The monopoly of high-tech has become a key means for large countries to control developing countries. From the mid-1980s to the present 15 years or so, the state has made a lot of capital, introduced a lot of industries, products and manufacturing technologies, and finally formed independent development and self-development. The goals of the ability, development of high-end products and testing capabilities have not been completed; manufacturing technical talents have not been developed, and there have been many losses. Policy mistakes have caused the country's strategy of exchanging some foreign markets for advanced technology to be unfulfilled and completed. This issue is worthy of consideration by the national authorities, the Ministry of Science and Technology, the Economic and Trade Commission, the Bureau, the financial and economic management research and decision-making departments.
Focus on the adjustment of talent policy, technological innovation and development policies, promote the optimal flow of talents, optimize the combination of funds and mechanisms, promote the orderly and reasonable knowledge economy, and conform to the development and transformation of the trend of the times.
Second, the middle of the piezoelectric competition hotspots and selection principles in the piezoelectric products competition hot products: metal closed switch equipment in the cabinet, FC fuse + vacuum contactor cabinet ring network cabinet: SF6 ring network cabinet, modular or other types of ring Net cabinet high voltage fuse (current limiting fuse), full range fuse, XRNT series fuse, its high-voltage arrester with ±20% of the characteristic error of within ±10%, zinc oxide arrester, ZnO arrester insulation with silicone rubber skirt, Box-type substation for the insulation of new products (including insulators, fittings, assemblies, busbar clamps, enclosed busbars, etc.): the principle of independent development, American, Western European and other models. The principle must be: Products that are welcomed and accepted by the market and users; don't squeeze a boat, go with the market, don't go with the factory, have your own direction and positioning.
In market research, technicians can join the sales team to learn about the market and make friends with users. Get the latest market information.
Take the factory door and engage in the road of cooperative development.
Emphasis on the confidentiality of trade secrets, business secrets are mainly: market trends, industry policies, price information, product market share, product structure adjustment program, product know-how.
Third, the introduction of intelligent switchgear (a) medium voltage switchgear intelligent technology is mainly reflected in: the use of intelligent information processing system. Diagnosis and monitoring of faults and fault precursors of the switchgear body.
Busbar and cabinet temperature, online monitoring and over-limit monitoring; online monitoring of operating characteristics such as circuit breaker opening and closing speed; online monitoring of mechanical performance of operating mechanism; online monitoring and alarm of insulation level.
Intelligent anti-missing operating system.
Prompt and pre-operation of various operations; lockout of operation check and misoperation; prohibition of operation prompts and operation condition prompts; secondary functions of switchgear: intelligence of measurement, signal, protection, control and telecontrol.
Remembrance of grid faults: recording, logging, simulation replay, providing analysis basis.
Fault analysis expert system: locate and quantify the accident, determine the cause and solution.
Expert assessment of current operating conditions and operational maintenance instructions.
The technology of intelligent switchgear is still in the research and development stage, and some technical difficulties have not yet been solved, especially the sensing technology of on-line monitoring of the switchgear body has certain difficulty.
At present, the intelligent device that can reach the application level is mainly to replace the conventional secondary device with the microcomputer function of the secondary function of the switchgear.
Digital relays or distributed automation devices currently have various brands of secondary functions and microcomputers for switchgear. The principle and function are similar, and the common point is that they can completely replace conventional secondary devices. It simplifies the secondary wiring, improves the safety and reliability, is easy to maintain, has strong functions, superior performance, and can have a communication interface, which provides a basis for realizing the unattended operation of the integrated automation of the power station. The name of the device has not been uniformly determined. Calling the law, some are called digital relays, some are called distributed automation devices, etc., we tentatively set digital relays to illustrate.
The structure of digital relays Domestically produced digital relays are generally based on Intralox's 8DC196 single-chip microcomputer, plus analog input channels, digital input channels, pulse input channels, and switching output channels are converted by current and voltage. And LCD display screen operation keys, communication interface and power supply.
Analog input and power supply, voltage conversion, voltage and current acquisition channels, directly with a CT, 0-5A and TP, -100V interface. The current and voltage frequency conversion adopts special high performance small CT, small TP, strong current 0-5A, voltage 0-100V through small CT small PT to 0-5V signal, through low pass filter, sample holder, send Into AD conversion, sampling using frequency tracking, complete AC acquisition technology, using half-wave or full-wave Four's algorithm, sampling frequency is generally 12 o'clock every week, calculate the initial phase angle of voltage, current, mass and frequency, derived calculation PQcs
The switch input generally adopts anti-interference technology such as photoelectric isolation, which is used for various position signals of the switch cabinet and circuit breaker status signals, operating mechanism energy storage signals and operation blocking signals.
Pulse input, generally use anti-interference technology such as photoelectric isolation, for the calculation of the electrical energy of the pulse watt-hour meter.
The switch quantity output adopts the photoelectric isolation technology for the circuit breaker to separate and close the operation, and has the control circuit disconnection operation and the loop power supply loss signal.
The liquid crystal display and operation keys are used as a human-machine interface, and are used to set various parameters, operating parameters and alarm numbers.
For networking purposes.
Power supply for each voltage level required by the device.
Functional feeders for digital relays: quick-break, over-current, ground, reclose, low-cycle capacitors: quick-break, over-current, ground, over-voltage, low-voltage, differential, unbalanced, unbalanced, c. Signal: circuit breaker Opening and closing position trolley working test position energy storage state grounding knife division, joint position blocking signal, reclosing lock, hydraulic/air pressure, SF6 air pressure blocking control loop power loss and disconnection various protection actions, time, type control: Circuit breaker opening control fault recording: 2S100 weeks before and after the fault (optional) phase voltage, current line voltage, zero sequence current waveform, and readout function, correctly read the mass and mutual at each moment Relational telecontrol: Through the communication network, realize the installation of telemetry, remote signaling, remote control and remote adjustment digital relay on the switchgear. a. Digital relays are generally installed in the instrument cabinet of the switchgear.
b. Digital relays usually have terminals or sockets behind the board.
Current loop: The general measurement protection is separated, the measurement loop is connected to the measurement CT, the protection loop is connected to protect the CT, and the current loop is subjected to the test terminal.
Voltage loop: Generally connected with three-phase five-column voltage mutual inductance, draw three-phase voltage from the PT cabinet, and connect the digital relay through the fuse. The same is true for the open triangle voltage.
220V, directly from the auxiliary contact of the switchgear, the signal power is generally supplied by digital relay.
The control loop is directly connected to the digital relay sub-gate and the closing terminal to access the split, closing coil and common grounding point respectively.
The digital device generally has a power supply from DC/220V + KM-KM, connected through a low-pressure air switch, and the air switch acts as a power switch for the secondary control operation.
(Continued from page 10) Lines and contactors are implemented. There is a large amount of wiring work here, which increases the cost and probability of failure accordingly. The SCU unit uses software to implement all interlocks in the cabinet.
The SCU device has a monitoring function such as a trip circuit that continuously monitors the circuit breaker, identifies a gap in such a loop, and displays it before the fault occurs; measures the number of breaks and breaking current of the circuit breaker, and burns the contact When prompted, the switchgear user can make the necessary repairs to replace the regular maintenance, measure the movement time of the breaking element and the energy storage time of the energy storage element, and compare it with the set nominal value, if there is a deviation, issue Alarms or corresponding displays, hardware and software technology self-monitoring to ensure timely detection of faults.
In the fourth quarter of 1993, CalorEmag put the first ZX1 intelligent gas-filled cabinet into operation. In 1997, it exhibited the double-bus ZX2 type inflatable cabinet. The product uses a stainless steel housing, a gas-insulated central module, a high-performance vacuum circuit breaker, plus configuration, modern control and protection (SCU), which greatly increases automation and expands functionality to ensure reliability and safety. The product is largely maintenance free.
This article introduces the intelligent development trend of circuit breakers and switchgears by taking several large European companies as examples. The second modernization and intelligence have become the trend of contemporary development, showing the development of switches and switchgear to high-end.
The use of modern sensor technology, digital control technology and microprocessor technology in switches and switchgear makes it possible to modernize and intelligentize the secondary technology. Intelligent technology greatly improves the reliability of the equipment and increases the function; it is conducive to maintenance, change to "regular maintenance" as "state maintenance" to detect faults early, prevent problems before they occur; secondly, without conventional electromagnetic components, simplify the structure The size of the switch cabinet is reduced, and a large amount of wiring work is saved, which is beneficial to reducing costs and reducing wiring errors.
The modern secondary control and protection device integrates protection, control, monitoring and communication to meet different requirements of users. It is installed on the switch and the switch cabinet at a glance, easy to operate and easy to use.
In China, intelligent switches and switchgear have reached the agenda, causing general attention in all aspects of the country. The Jiangsu Electrotechnical Society held a seminar on intelligent switches and switchgears for the second time last year and this year, which brought a good start for the development of switchgear and switchgear in China. Intelligent switches and switchgear are not only a matter of the switch industry, but also All parties work together to achieve success. I believe that with the joint efforts of all parties, China's switch and switchgear will have great development in terms of intelligence, and keep up with the world trend.
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