The application of ecological architecture in the design?

I. Basic Principles of Power Grid Design

1. Investment Status The investment of the power grid mainly consists of two parts: transmission line part and substation part. For the transmission line investment, there are mainly the following three kinds: the first circuit investment, the second circuit investment and the third outgoing corridor and so on. If the voltage level in the grid is different, the investment will be different.

2. Operation costThe operation cost of the grid mainly includes three parts: management cost, maintenance cost and network loss cost. In the design of the grid, the power loss generated by different design options are different, so not only to improve the cost but also must increase the relevant equipment for power supplementation, these are invariably increased grid investment, so in the final economic comparisons must be considered when these factors.

3. Flexibility and adaptabilityFlexibility refers to the design of the grid after the start of operation, in the event of a variety of circumstances, that is, maintenance, faults, and other situations are able to operate safely and reliably. Adaptability refers to the design of the grid in the application of the region to increase the number of new users or load growth, can be relatively easy to realize the expansion, and the original electrical equipment can be used to maximize the efficiency. At the same time, with the rapid development of the power grid, the short-circuit current in the grid will also increase, in the design, especially to keep the short-circuit current can not exceed a specific range, otherwise the switching equipment is very easy to cut off the ability of the problem. Several of the above principles in the design of the program comparison, there are contradictions, so usually design a variety of programs for comprehensive comparison.

Second, the basic types of grid design wiring

Usually, the grid design wiring types include the following: simple closed wiring, complex closed wiring, open wiring without backup and open wiring with backup.

1. Simple closed wiring closed grid wiring refers to the grid when the need to enable standby power, usually choose a different outlet corridor circuit for power supply wiring. This wiring design of the grid usually includes a ring grid and two ends of the power grid, with the following two advantages: First, the substation can ensure that there are two different transmission lines, high reliability of power supply; Second, the transmission line distance is relatively short, can effectively save the power grid investment.

2. Complex closed wiring in the grid design, for more than 110kV power supply and distribution often use the complex closed mode, the way the grid consists of two parts: ring grid and double circuit. Due to the 110kV above the grid transmission capacity, the reliability of the grid requirements are also higher, operation and relay protection mode is also more cumbersome, complex, so the choice of the grid wiring usually computer-aided analysis.

3. No standby open wiring mode if the distribution network in the receiving substation has no standby power, this grid is called open grid. In the distribution network, the probability of failure and the length of the transmission line has a close relationship, the reliability of this wiring method is low, usually only used in those less important small substations or users of power supply. Commonly used wiring methods are radial and trunking type.

4. open wiring with standby in order to improve the safety and reliability of power supply, for 2.3 listed in the wiring can be improved to increase the standby power equipment. For example: for the above radiation type wiring, can use two transmission lines to power supply, improve the reliability of the power supply system.

Three, the application of grid design

Often, the design of the power grid to design more than a few programs, in the actual selection of all aspects of the comparison, so as to select the most cost-effective program. In the comparison of choice, mainly through the analysis of technical indicators and economic factors to choose the best program. Technical indicators to analyze the feasibility of the program in the power supply and distribution technology, the main indicators include: trend calculation, safety calibration calculation, short-circuit current calculation. If the grid includes long-distance high-voltage transmission, must also be carried out under different circumstances of stability calibration.

1. Analysis of technical indicators

(1) the main function of the trend calculation trend calculation is to analyze the operation of the grid in various situations and adaptive capacity, check whether part of the electrical equipment will be overloaded after putting into operation, the voltage borne by each line bus is out of the rated range.

(2) safety checking calculation safety checking calculation includes two aspects, power grid static safety technology analysis and dynamic safety technology analysis. In the static analysis of the grid design, the main check when one of the electrical components failures can not be normal operation of the grid trend distribution, through the distribution of information to determine whether the other electrical components overload and overvoltage. For power grids above 220kV, in order to ensure safety, dynamic safety calibration must be carried out, that is, the stability calculation of the grid in various operating modes. If the above calibration can not meet the requirements of normal operation of the grid, it is necessary to take appropriate remedial measures, such as: appropriate increase in transmission lines, increase the cross-sectional area of the conductor, increase the reactive power compensation equipment in the grid, improve the stability of the grid, etc., in order to ensure that the entire grid safe, reliable and stable operation, or else to discard those who do not meet the requirements of the design program.

(3) short-circuit current calculation of short-circuit current calculation of the main function is to determine when there are different types of faults, the distribution of short-circuit current of the power grid, the calibration of the thermal and dynamic stability of the electrical equipment and the corresponding line circuit breaker's ability to automatically cut off. Part of the power system according to different voltage levels, for the corresponding line circuit breaker's maximum cutting capacity is also carried out the corresponding restrictions. The grid program should ensure that the short-circuit current can not exceed the predetermined limit, otherwise it is very easy to cause the grid to replace a large number of circuit breakers, increasing the investment cost of the grid.

2. Economic analysis in the technical indicators to meet the basic requirements, after the selected grid design program for economic comparison, select the best cost-effective program. The economic comparison can be made using a variety of different engineering methods, such as: the present value of the cost comparison method, equal annual cost method. At the same time, due to the rapid development of modernization, people pay more and more attention to the reliability of the power grid, the design of the power grid in addition to the analysis of the above indicators, but also must be analyzed and calculated in the operation of the reliability of the power grid, which will result in the corresponding loss of power outages, which should also be taken into account in the design of the power grid.

Four, conclusion

In summary, the design of the power grid is complicated, the indicators must be carefully and repeatedly consider the calculation, the author combined with their own practical experience to explore this issue, I hope to play a certain role in helping colleagues.

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