One of the provisions of the elevator distribution 1, GB50310-2002 "elevator project construction quality acceptance specification" issued a notice specifying the GB50182-93 specification is repealed. The original GB50182-93 2.0.1 states: elevator power supply should be dedicated, and should be sent directly to the machine room from the building distribution room; 2.0.3 states: machine room lighting power supply and elevator power supply is separate, and should be set up in the machine room near the entrance to the lighting switch has been repealed. 2, GB50310-2002 3.3.2 states: all types of elevator load grading and power supply requirements should be In line with the current national standard "power supply and distribution system design code" provisions of the fire elevator in high-rise buildings, should be in line with the "high-rise civil building design and fire code" provisions. Explain that the elevator power supply emphasizes the load grading and power supply requirements, not cool elevator power supply should be dedicated, should be sent directly to the machine room from the building distribution room, machine room lighting power supply and elevator power supply separately. How to consider the elevator power distribution power? It is recommended to use the following norms: 1, GB50055-1993 "General Electric Equipment Distribution Design Code" 3.3.3 states: each elevator or escalator power supply should be set up to isolate the electrical and short-circuit protection appliances. For elevator machine rooms with multiple power feeds, each feed should be installed.2. GB50055-1993 "Code for Distribution Design of General Electric Equipment" stipulates in 3.3.6 that: the lighting power supply of the bridge compartment can be obtained from the elevator power supply in front of the isolating appliance, and isolating appliance and short-circuit protection appliance should be installed.3. GB50310-2002 4.10.3 stipulates that: the main power switch shall not Cut off the following power supply circuits (1) bridge car lighting and ventilation (2) machine room and pulley room lighting (3) machine room, bridge roof and pit socket power (4) shaft lighting (5) alarm device 4, GB50310-2002 4.11.1 in the provisions of the relevant short-circuit overload protection: power circuits, control circuits, safety circuits, must be set up with short-circuit protection devices; power circuits must have an overload protection device. 5, GB50310-2002 4.2.4 in the provisions of: machine room should be equipped with fixed electrical lighting, floor surface illumination should not be less than 200lx. machine room should be set up in one or more power outlets, in the machine room at the entrance to the appropriate height of the room should be set up at the appropriate height of a switch to control the machine room lighting power. Second, the design requirements of anti-static engineering (reference anti-static engineering technical regulations DGJ08-83-2000) 1, anti-static engineering classification: Level 1: microelectronic circuit manufacturing and testing sites. National security and head of department information management and command center. 2 level: program-controlled communication room, large and medium-sized computer room; important economic sector automated monitoring and control, scheduling system. 3 level: general computer terminal room, intelligent buildings in the computer operation of the office. There is external electromagnetic interference, the environment must provide the most basic anti-static protection of electronic equipment in the place. 2, anti-static project in the distribution and lighting requirements 1) anti-static project is appropriate to use underground cable into the line, the power supply line should be in accordance with the relevant national standards to take lightning protection measures. Low-voltage distribution lines should be laid with copper-core shielded wires, copper-core shielded cables or copper-core insulated wires through the steel pipe, and should be shielded and grounded. 2) anti-static engineering in electronic equipment and facilities, power lines, grounding lines, signal lines and communication lines should be laid separately. Power lines should be as far away as possible from the signal line and communication lines, avoid side-by-side laying, when unavoidable, should take appropriate shielding measures. Electronic equipment and facilities should be set up separately for working power sockets and ordinary electrical sockets, and there should be a clear distinction between the signs.3) anti-static project lighting design lamps and lanterns should be designed to meet the requirements of the workplace, when there is anti-electromagnetic interference requirements should be in line with the nuisance limits, harmonic current limits and flicker limits of the standard. Specific reference to the international standard IEC61000-3-2 "harmonic current emission standards", IEC61000-3-3 "equipment in the low-voltage power supply system voltage fluctuations and flicker limit" and CISPR "electrical lighting and similar equipment radio nuisance characteristics of the measurement methods and limits" implementation. 3, anti-static engineering in the grounding 1) antistatic grounding system in the access to the earth Antistatic grounding system should be set up before the equipotential antistatic grounding reference plate, from the reference plate lead to the grounding trunk line, its cross-sectional area should not be less than 100m ㎡, and should be insulated shielded cable. Grounding trunk lead to the need to take anti-static grounding area should be set up in the area of the grounding grid or closed copper ring connection. In the anti-static grounding system between the various connection parts of the resistance value should be less than 0.1 Ω. (2) anti-static project must have an effective DC grounding (logic ground, signal reference ground) system, the provisions of this specification applies to the DC ground ground to earth grounding system. DC working grounding reference potential should be taken from the total equipotential copper row, grounding conductor and the total equipotential copper row for single-point connection. DC work grounding trunk should be set from the total equipotential copper row or near the total equipotential copper row DC grounding reference plate, and should be laid in a special weak well. When the DC grounding trunk leads to the distribution area of the electronic equipment, the regional auxiliary equipotential copper row should be set up accordingly, so that the equipment grounding lead from the auxiliary equipotential copper row on the nearby ground connection. 3) DC grounding trunk should be laid separately insulated, and should use insulated shielded cables, the main trunk cross-sectional area should be not less than 100m ㎡, the branch trunk cross-sectional area should be not less than 34m ㎡, system DC resistance between any two points in the system should be limited to 0.02Ω or less. DC grounding system of the reference plate and auxiliary equipotential copper rows should be individually insulated frame, should not be located in the power supply distribution box (cabinet) and sub-distribution box, the size of its selection should be 150-100-6mm. equipment grounding lead should be from the DC grounding special grounding connection box, and should be used for copper shielded conductor laying. Third, the principle of selective design of protection appliances (reference materials civil building design technical measures) 1) the basic requirements for selective action of protection appliances 1, the last level of protection appliances required to cut off the fastest possible fault circuit, without affecting the process requirements, preferably instantaneous cut off. 2, the last level of protection using circuit breakers, it is desirable to have a short delay time to release, the setting of the current and the extension of the time can be adjusted to ensure that the next level of protection first action. 3, the next level of protection first action. The lower level of protection first action. 3, the upper level of protection with fuse protection, its inverse time characteristics should be compatible with each other, with the overcurrent selection ratio to give assurance. 4, from the low voltage side of the transformer distribution circuit to the power equipment between the number of distribution levels should not exceed three. For non-important loads may not exceed four levels. 5, the distribution system between the first and second level of protection appliances should have action selectivity. And it is suitable to use selective type protection appliances, and non-selective cut-off can be used for non-important loads. 2) Inter-stage cooperation between circuit breaker and circuit breaker 1, when there is a big difference in the expected short-circuit current at the outlet end of the circuit breaker of the upper and lower levels and the upper and lower levels of the circuit breaker are equipped with instantaneous detent, the instantaneous detent of the upper level of the circuit breaker should be larger than the expected short-circuit current of the lower level, in order to ensure selective protection. 2, when the upper and lower levels of the circuit breaker are very close, the outlet end of the circuit breaker should not exceed three levels. 2, when the upper and lower levels of circuit breaker is very close, the difference between the expected short-circuit current at the outlet end is very small, then the upper level circuit breaker should be selected with a short delay release, so that the delayed action to ensure that there is a selective cooperation. 3, in order to facilitate the coordination between the upper and lower levels of coordination, in general, the first level of protection appliances (such as transformer out of the line on the low-voltage side of the main switch) is suitable to select the overload long-delayed, short-circuit short-delayed (0 ~ 0.5s adjustable time delay) protection characteristics, no short-circuit instantaneous detent. No short-circuit instantaneous release device. According to the importance of the second-level distribution circuit protection appliances, it is appropriate to use overload long delay, short-circuit short delay, short-circuit instantaneous and ground fault protection. Bus contact switch should be equipped with overload long delay, short circuit short delay protection. The first level and the second level of short-circuit short delay protection appliances, there should be a level difference time, should not be less than 0.1 ~ 0.2 s. 4, selective protection appliances, the upper level of protection appliances, overload long delay and short-circuit short delay rectification current, it is desirable to be not less than the next level of protection appliances of the rectification value of 1.3 times. To ensure the selectivity of the action between the upper and lower levels. 5, when the upper level protection appliance is a selective appliance, and the next level of protection is non-selective protection appliance, the following conditions should be met: (1) the upper level protection appliance short-circuit short-delay detent should be not less than the lower level protection appliance short-circuit short-circuit instantaneous detent rectified current of 1.3 times. That is: I1 (l2) ≥ 1.3I2 (l3) (4.4.3-1) where I1 (l2) - the upper level of protection appliances, short-delay off-trigger setting current; I2 (l3) - the lower level of protection appliances, instantaneous off-trigger setting current. (2) Upper level protection appliance instantaneous detrigger setting current, should be greater than the lower level protection appliance outlet end of the single-phase short-circuit current of 1.2 times. That is: I1 (l3) ≥ 1.2I2 (ld1) (4.4.3-2) where I1 (l3) - the upper level of protection appliances, instantaneous off-trigger fixing current; I2 (ld1) - single-phase short-circuit current of the outlet end of the lower level of protection appliances. Note: If the selection of the upper level of protection switch of the instantaneous off-trigger setting current is less than or equal to the next level of protection switch outlet short-circuit current, the lower level of protection switch should be selected to limit the current type protection switch to ensure the selectivity of the requirements. 1/3 123NextEnd6, the upper and lower levels of protection appliances should be selected to select non-selective switch should increase the upper and lower level of protection between the level of the off-trigger setting current between the appliances of the level of difference, generally in accordance with the Generally, it can be determined according to the following principles. (1) The setting current of the long-delay detent of the upper level protection appliance should be not less than two times of the setting current of the long-delay detent of the next level protection appliance. That is: I1 (l1) ≥ 2I2 (l1) (4.4.3-3) where I1 (l1) - the upper level of long-delay detentor setting current; I2 (l1) - the lower level of long-delay detentor setting current. (2) The upper level of protection appliance instantaneous tripper setting current should not be less than 1.4 times the lower level instantaneous tripper setting current. That is: I1 (l3) ≥ 1.4I2 (l3) (4.4.3-4) where I1 (l3) - the upper level of protection appliance instantaneous off-trigger setting current; I2 (l3) - the lower level of protection appliance instantaneous off-trigger setting current. 7, miniature Circuit breaker selective fit between the upper and lower levels can be selected according to Table 4.4.3. Table 4.4.3 Selective matching between upper and lower levels of miniature circuit breaker (breaking capacity 6KA) Overcurrent tripper rated current (A) Upper level tripper rated current (I1) 20 25 32 40 50 63 80 100 Lower level tripper rated current (I2) 10 16 25 25 25 32 40 50 633) Matching between protective appliances and conductors 1. Conductors and cables should satisfy the load carrying capacity for long term full load operation. 2. flow rate. The long-delay setting current of the circuit breaker or the rated current of the fuse should be less than or equal to the continuous allowable load capacity of the conductor or cable. That is: IzdI(Ir) ≤ 1 (4.4.8-1) I2 where Izd1 - circuit breaker long-delay striker setting current; Ir - fuse rated current; I2 - long term allowable load current of conductor or cable. - conductor or cable long-term permissible current-carrying capacity, when the conductor is laid in different ambient temperatures and different laying conditions, should be multiplied by a correction factor. 2, in order to ensure the safety of conductors and cables in short-circuit conditions of its cross-sectional area and short-circuit current relationship should meet the following requirements: Id ≥ √t (4.4.8-2) k where Id - Three-phase short-circuit current rms value (A); K - and conductor material related coefficients; t - short-circuit current duration, take 5s. 4) In order to ensure the reliable operation of the protective appliances in the case of ground fault, it is required that the circuit breaker's Instantaneous rectifying current or short delay rectifying current, fuse fuse rated current should be less than the ground fault current. That is: KrIr≤Id (4.4.8-3) KdIzd≤Id (4.4.8-4) where Id - earth fault current Ir - fuse rated current Izd - instantaneous or short delay rectification current of circuit breaker, fuse rated current of fuse should be less than the earth fault current. - circuit breaker instantaneous or short delay rectification current Kd - coefficient used for circuit breaker, take 1.3; Kr - coefficient used for fuse, see Table 4.4.8. Table 4.4.8 coefficient used for fuse Kr Fuse rated current (A) 4 ~ 10 16 ~ 32 40 ~ 63 80 ~ 200 250 ~ 500 ≤ 5s 4.5 5 6 7 ≤ 0.4s 8 9 10 11 - in the TN system neutral grounding transformer low-voltage side of the distribution line when a ground fault occurs, the value of its ground-fault current can be determined by the following formula: Id = Kr? -(5) where Rφp, Xφp - transformer and conductor phase resistance, reactance sum. If the requirements can not be met, leakage current protection should be used. Fourth, the computer power distribution circuit of the protection of electrical appliances 1), ground fault protection using leakage current switch protection should be taken into account and each computer leakage current to prevent false action. General 17 "monitor computer, power capacity of 300W (including the monitor for 220W or so), COSφ = 0.5 ~ 0.7, each computer leakage current of about 3.5 mA; BV-4mm2 wire through the steel pipe when the leakage current of about 52 mA / KM. 2/3 HomePrevious123NextLastIn order to protect personal safety. Leakage protector set the action current to take 30mA, if 10 computers work at the same time, the distribution circuit length of 50 meters, the leakage current of the circuit sum of 37.6mA, greater than 30mA, will occur false action. Therefore, it is advisable to limit the number of computers in the circuit. General requirements of the distribution circuit of the leakage current protector set the action current to take 2.5 times the sum of the circuit leakage current. 2), the computer distribution circuit of the operation of the overcurrent if the distribution circuit is connected to the computer socket 8, and used at the same time. Its rated operating current is: Pe1 300 Ie1 = = = 1.95 Ue * COSφ 220 * 0.7 so, IΣ = 19.5 * 8 = 15.6 A, the design selection of circuit breaker protection, the rated current to take 20 A. In practice, for example, the school's computer classroom, the students almost do not turn off the monitor during class, the class once the circuit is often closed to cause a trip. Analyze the reasons are as follows: computer power factor of 0.5 ~ 0.7, but it is capacitive load. When the switch is closed, it is equivalent to adding a step voltage. Because the characteristics of capacitive circuit is the voltage can not be sudden change, so the current in the circuit will produce a sudden change, causing the operation of overcurrent. The process of sudden change in the loop can be described by a second-order differential equation of R-L-C. X(t) is the current variable, which is written as follows after substituting some parameters: (Note: the following parameters are for illustration only.) There are many ways to solve this second-order differential equation. The results show that: the amplitude of the inrush current is 0.825 units, the amplitude of the AC steady state current is 0.131 units, and their ratio is 6.3 times. See the following characteristic curve: according to the miniature circuit breaker action time characteristics, about 0.01-0.02s, so the circuit breaker action to cut off the current should be the circuit of the full current of the inrush current. According to the different types of miniature circuit breakers, in order to prevent false tripping, should increase the rated rated current or multiplier. Table 1 for household and similar places with circuit breaker release characteristics Table 1 release type circuit breaker release rated current In Passing current Specified time (release or non-release limit time) Expected results B, C, D ≤63 1.13In ≥1h non-detachment ＞63 ≥2h B, C, D ≤63 1.45In ＜1h detachment ＞63 ＜2h B, C, D ≤32 2.55In 1s B, C, D ≤32 2.55In 1s ～60s Detachment＞32 1s～120s B All values 3In ≥0.1s No detachment C 5In D 10In B All values 5In ＜0.1s Detachment C 10In D 50In Note: B, C, D is the instantaneous detachment type: B detachment current＞3～5In, C detachment current＞5～10In, D detachment current＞10～50In. users can choose it according to the needs of the protection object, or select it according to the needs of the protection object. The user can choose one of them according to the need of the protection object.
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