Electrical design of the hottest residence

2022-09-22
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Abstract: with the development of China's social economy and the great improvement of people's living standards, all kinds of household appliances are gradually increasing, especially high-power appliances such as air conditioners and large screen color TVs, Make the residential design develop from pure lighting to multi-function

key words: electrical load, distribution system, conductor and equipment selection, fire protection system, lightning protection and grounding, intelligent Untitled Document with the development of China's social economy and the great improvement of people's living standards, all kinds of household appliances are gradually increasing, especially high-power appliances such as air conditioners and large screen color TVs enter ordinary families, Make the residential design develop from pure lighting to multi-function. 1. For the prediction of residential power load, we divide the residential area into three categories: small residential area of less than 60m2, medium-sized residential area of 60 ~ 100m2, and large residential area of more than 100m2. In general, the power load of small residential lighting is 500W, the power load of entertainment (including TV, stereo, computer, etc.) is 950W, the power load of kitchen (including rice cooker, electric water heater, etc.) is 3500W, and the power load of toilet (washing machine, exhaust can be appropriately added with some PP (subject to the test); Fan) the load sepiolite is 1170w of aqueous magnesium silicate, and the power load of air conditioning is 2250w. The total power load of the above types is 8370w, medium-sized residential buildings multiply by 1.3 coefficient 10881w, and large residential buildings multiply by 2.6 coefficient 21762w. According to the statistical survey, the peak of residential electricity load is after dinner in summer. At this time, the electricity load includes: TV, refrigerator, electric water heater, disinfection cupboard, computer and air conditioner, accounting for 40% of the residential electricity load. According to the design manual, the demand coefficient is 0.4 ~ 0.6. Therefore, according to the actual situation, we can take 0.4 coefficient in our design, so the small residential load calculation is 3.5kw, and the medium-sized residential load calculation is 4.5kw, The load of large residential buildings is calculated as 8.5kw. 2. The power supply and distribution system of the residence, Jin Chengli, has been transferred to the marketing department. The power supply of the well-off residence is introduced from the substation of the community. It should adopt three-phase four wire (TN-C system), enter the switch box of the unit master electricity meter after repeated grounding, change it to three-phase five wire system (TN-S system), and then release it to all users. The distribution box should have short-circuit, overload and leakage protection, and the circuit breaker should choose a circuit breaker that can cut off the phase line - neutral line at the same time. One household one meter system should be adopted for residential power load measurement. It is suggested to set up the unit main switch and household electricity meter in a centralized way for management. Indoor power distribution system: with the increase of household appliances, in order to avoid the impact of electrical circuit overload and reduce harmonic voltage, the indoor power distribution system should adopt the form of multiple circuits, at least lighting circuit, general socket circuit and air conditioning circuit should be set, and the kitchen and shower room can also be set as separate circuits if necessary. In addition, considering the development of home office and informatization, a special circuit should be added. 3. The selection of wires and electrical equipment whether the selection of indoor and outdoor wires and electrical equipment is reasonable or not is directly related to the safety and economic benefits of residential electricity, so wires and related electrical equipment must be reasonably selected in engineering design. (1) Selection of Conductor: the selection of conductor is mainly to determine the model and specification of conductor. Its principle is to ensure the quality and safety of power distribution and save materials, so as to be economical and reasonable. The wire type shall be selected according to the working voltage and laying environment; The specification (section) of the conductor can be selected according to the following requirements: ① it has sufficient mechanical strength. In order to prevent wire breaking accidents, the conductor must have sufficient mechanical strength. Generally, the calculated current of the lighting circuit is small (<10a), and the conductor should be selected according to the mechanical strength. ② It can ensure the safe operation of the conductor. When selecting the conductor, ensure that its safety current is greater than the long-term maximum load current, and pay attention to the following points: A. appropriate allowance should be left when selecting the incoming line and the section of the trunk line; b. The neutral wire in the single-phase system shall have the same section as the phase wire; c. The current carrying capacity of the neutral line in the three-phase four wire system shall not be less than the maximum unbalanced load current in the line. The conductance of the neutral wire used for neutral wire protection shall not be less than 50% of the phase wire conductance of the line. The lighting line of the gas discharge lamp is affected by the third harmonic current, and the cross section of the neutral wire shall be selected according to the maximum phase current. ③ Ensure voltage quality. For residential buildings, the line voltage loss from the power lead-in end to the load end should not be greater than 2.5%. If the line voltage loss value is greater than the specified allowable value of voltage loss, the conductor section should be increased to ensure the voltage quality of the line. In short, the actual use and future development needs should be considered when selecting conductors, with appropriate allowance to reduce voltage loss and ensure the safe, reliable, economical and effective use of conductors. (2) Selection of electrical equipment: electrical equipment mainly refers to power distribution box, electricity meter, control switch, leakage protection switch and power socket. Whether the selection of electrical equipment is reasonable or not directly affects the quality of the project. When selecting, the model and specification of electrical equipment should be reasonably selected according to the residential load, installation requirements, use environment, working voltage and working current of the equipment. Pay attention to the capacity grade of the equipment rather than small, but avoid selecting too large to cause waste. Generally speaking, select a higher grade on the basis of calculating the working current. In order to ensure its quality, electrical products that comply with IEC standards of the International Electrotechnical Commission and relevant domestic GB and JB industry standards and have product quality approval certificates should be selected. In short, the selection of electrical equipment should be as safe, reliable and economical as possible. 4. Lightning protection and grounding (1) lightning protection contents and measures. Lightning protection can generally be divided into three parts: direct lightning protection, induction lightning protection and high potential intrusion prevention. As far as direct lightning protection is concerned, it is generally to install lightning arresters at the parts of the roof that are vulnerable to lightning strikes, and then connect them reliably with the grounding device with very small grounding resistance through the downlead. During installation, it should be noted that the protruding metal parts of the roof should be reliably connected with the lightning rod and belt. At present, roof slab reinforcement is generally used as lightning protection, column main reinforcement as downlead, and foundation reinforcement as grounding device, which is a more practical and economic practice. In order to prevent the harm of inductive lightning and high potential invasion, the iron leg support of insulator can be reliably grounded at the entrance and exit of cable, and lightning arrester or other types of overvoltage protector can be installed at the same time. In addition, it is necessary to emphasize equipotential bonding, which means that all metal objects in and around the building should be electrically connected in the design and construction, so that the whole building space can become a good equipotential body, which can effectively reduce different metal parts in and around the building

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