Selection Of Switch For Lighting Circuit Of Elevator Shaft

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Time of issue:2021-08-05
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(Summary description)　　Through an example of a road lighting project in a high-rise residential building, the problems of single-phase short-circuit protection setting and sensitivity verification in the elevator shaft lighting power distribution system are discussed. In the TN-S system, the B-type miniature circuit breaker can be used for the elevator shaft lighting power distribution trunk switch. The lamps should be added with compensation capacitors, and the power factor of the lamps should be greater than 0.9.

　　At present, there are more and more high-rise civil buildings, and high-rise buildings are equipped with elevators. For elevator shaft lighting, the code has clear requirements. Article 9.4.5 of the Civil Building Electrical Design Code (JGJ16-2008) stipulates: lighting should be installed in the elevator shaft, and the illuminance should not be less than 50lx, and the following requirements should be met: ① Install a lamp within 0.5 meters from the high point and the low point of the hoistway. One lamp should be installed at a distance of no more than 7m in the middle, and control switches should be installed in the engine room and the pit; ②The power supply for the top of the bridge and the hoistway. Easy to be 36V; when 220V must be installed, a residual current operated protector should be installed.

　　For the elevator shaft lighting distribution lines of high-rise buildings, most people think that the switches and wires should be selected according to the calculated current. This is generally not a problem for buildings that are not very tall, but for 30-story or higher-rise buildings. For buildings, it is not enough to only consider the overload protection of the line. The characteristics of the lamps, the short-circuit protection of the line, and the voltage loss should also be considered.

　　Project example

　　A 32-story residential building with a height of 3 meters. There is a power distribution room in the basement, and the public power is from two outdoor box transformers (capacity 630KVA, box transformer with 3m long copper bus 3 (80x80) + 1x (63x6.3)), respectively lead one 380/220V power supply to For the power distribution cabinet in the basement, both circuits use ZRYJV22-4x150mm2 cables, and the line m1 is 50m long.

　　After being distributed by the power distribution cabinet, they are led to the fan and emergency lighting. For emergency lighting lines, trunk type + radiation type power supply is used, two trunk lines use NHYJV cables, the specification is 4x35+1x16mm2, the line m2 is 100m long, each four floors is equipped with an emergency dual power switch box, and the roof computer room lighting is separately equipped with a pair of power switch boxes , Adopt the main line T connection to connect with the power supply main line.

　　The dual power switch box circuit of the roof machine room includes elevator shaft lighting, machine room lighting, machine room sockets, elevator shaft sockets, aviation obstruction lights and other circuits. The elevator shaft lighting circuit uses 220/36V (capacity 500VA) transformers to supply power. One lamp is installed within 0.5 meters of the low point, with an odd-numbered layer in the middle, a total of 18 lamps. The lighting adopts Philips compact energy-saving lamps, the power is 13W, the luminous flux is 900, the power factor after compensation is 0.9, and the lighting power distribution uses two BV10mm2 wires. The line m3 is 96m long.

　　The protection of the elevator shaft lighting distribution circuit should have overload protection, short circuit protection, and should avoid the starting current of the lamps.

　　When a short circuit occurs at the end of the line of this project, there are seven impedance components in the loop, including high-voltage system, 10/0.4kV transformer, low-voltage bus, low-voltage cable m1, low-voltage cable m2, 220/36V transformer, and low-voltage wire m3. According to the data in Tables 4-22~25 on pages 155~159 of the "Industrial and Building Power Distribution Design Manual" Third Edition, the impedance of the single-phase L-N circuit of each component can be calculated, and then the short-circuit current can be calculated. After calculation, the short-circuit current is, Id=105.2A.

　　The protection of the elevator shaft lighting distribution circuit should meet the following requirements:

　　1) The setting current of the long-time delay release of the low-voltage circuit breaker for lighting should be greater than the calculated current of the circuit. ,

　　2) The setting current of the instantaneous overcurrent release of the low-voltage circuit breaker for lighting should be 4~7 times greater than the calculated current of the circuit.

　　3) In order to ensure the sensitivity of the circuit breaker, the setting current of the instantaneous overcurrent release of the circuit breaker should be less than 1/1.3 times of the small short-circuit current at the end of the line.

　　For this project (18 sets of lamps), th

电梯井道照明线路开关的选择

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Selection Of Switch For Lighting Circuit Of Elevator Shaft

(Summary description)　　Through an example of a road lighting project in a high-rise residential building, the problems of single-phase short-circuit protection setting and sensitivity verification in the elevator shaft lighting power distribution system are discussed. In the TN-S system, the B-type miniature circuit breaker can be used for the elevator shaft lighting power distribution trunk switch. The lamps should be added with compensation capacitors, and the power factor of the lamps should be greater than 0.9.

　　At present, there are more and more high-rise civil buildings, and high-rise buildings are equipped with elevators. For elevator shaft lighting, the code has clear requirements. Article 9.4.5 of the Civil Building Electrical Design Code (JGJ16-2008) stipulates: lighting should be installed in the elevator shaft, and the illuminance should not be less than 50lx, and the following requirements should be met: ① Install a lamp within 0.5 meters from the high point and the low point of the hoistway. One lamp should be installed at a distance of no more than 7m in the middle, and control switches should be installed in the engine room and the pit; ②The power supply for the top of the bridge and the hoistway. Easy to be 36V; when 220V must be installed, a residual current operated protector should be installed.

　　For the elevator shaft lighting distribution lines of high-rise buildings, most people think that the switches and wires should be selected according to the calculated current. This is generally not a problem for buildings that are not very tall, but for 30-story or higher-rise buildings. For buildings, it is not enough to only consider the overload protection of the line. The characteristics of the lamps, the short-circuit protection of the line, and the voltage loss should also be considered.

　　Project example

　　A 32-story residential building with a height of 3 meters. There is a power distribution room in the basement, and the public power is from two outdoor box transformers (capacity 630KVA, box transformer with 3m long copper bus 3 (80x80) + 1x (63x6.3)), respectively lead one 380/220V power supply to For the power distribution cabinet in the basement, both circuits use ZRYJV22-4x150mm2 cables, and the line m1 is 50m long.

　　After being distributed by the power distribution cabinet, they are led to the fan and emergency lighting. For emergency lighting lines, trunk type + radiation type power supply is used, two trunk lines use NHYJV cables, the specification is 4x35+1x16mm2, the line m2 is 100m long, each four floors is equipped with an emergency dual power switch box, and the roof computer room lighting is separately equipped with a pair of power switch boxes , Adopt the main line T connection to connect with the power supply main line.

　　The dual power switch box circuit of the roof machine room includes elevator shaft lighting, machine room lighting, machine room sockets, elevator shaft sockets, aviation obstruction lights and other circuits. The elevator shaft lighting circuit uses 220/36V (capacity 500VA) transformers to supply power. One lamp is installed within 0.5 meters of the low point, with an odd-numbered layer in the middle, a total of 18 lamps. The lighting adopts Philips compact energy-saving lamps, the power is 13W, the luminous flux is 900, the power factor after compensation is 0.9, and the lighting power distribution uses two BV10mm2 wires. The line m3 is 96m long.

　　The protection of the elevator shaft lighting distribution circuit should have overload protection, short circuit protection, and should avoid the starting current of the lamps.

　　When a short circuit occurs at the end of the line of this project, there are seven impedance components in the loop, including high-voltage system, 10/0.4kV transformer, low-voltage bus, low-voltage cable m1, low-voltage cable m2, 220/36V transformer, and low-voltage wire m3. According to the data in Tables 4-22~25 on pages 155~159 of the "Industrial and Building Power Distribution Design Manual" Third Edition, the impedance of the single-phase L-N circuit of each component can be calculated, and then the short-circuit current can be calculated. After calculation, the short-circuit current is, Id=105.2A.

　　The protection of the elevator shaft lighting distribution circuit should meet the following requirements:

　　1) The setting current of the long-time delay release of the low-voltage circuit breaker for lighting should be greater than the calculated current of the circuit. ,

　　2) The setting current of the instantaneous overcurrent release of the low-voltage circuit breaker for lighting should be 4~7 times greater than the calculated current of the circuit.

　　3) In order to ensure the sensitivity of the circuit breaker, the setting current of the instantaneous overcurrent release of the circuit breaker should be less than 1/1.3 times of the small short-circuit current at the end of the line.

　　For this project (18 sets of lamps), th

Categories:Industry News
Author:
Origin:
Time of issue:2021-08-05
Views:0

　　Through an example of a road lighting project in a high-rise residential building, the problems of single-phase short-circuit protection setting and sensitivity verification in the elevator shaft lighting power distribution system are discussed. In the TN-S system, the B-type miniature circuit breaker can be used for the elevator shaft lighting power distribution trunk switch. The lamps should be added with compensation capacitors, and the power factor of the lamps should be greater than 0.9.

　　At present, there are more and more high-rise civil buildings, and high-rise buildings are equipped with elevators. For elevator shaft lighting, the code has clear requirements. Article 9.4.5 of the Civil Building Electrical Design Code (JGJ16-2008) stipulates: lighting should be installed in the elevator shaft, and the illuminance should not be less than 50lx, and the following requirements should be met: ① Install a lamp within 0.5 meters from the high point and the low point of the hoistway. One lamp should be installed at a distance of no more than 7m in the middle, and control switches should be installed in the engine room and the pit; ②The power supply for the top of the bridge and the hoistway. Easy to be 36V; when 220V must be installed, a residual current operated protector should be installed.

　　For the elevator shaft lighting distribution lines of high-rise buildings, most people think that the switches and wires should be selected according to the calculated current. This is generally not a problem for buildings that are not very tall, but for 30-story or higher-rise buildings. For buildings, it is not enough to only consider the overload protection of the line. The characteristics of the lamps, the short-circuit protection of the line, and the voltage loss should also be considered.

　　Project example

　　A 32-story residential building with a height of 3 meters. There is a power distribution room in the basement, and the public power is from two outdoor box transformers (capacity 630KVA, box transformer with 3m long copper bus 3 (80x80) + 1x (63x6.3)), respectively lead one 380/220V power supply to For the power distribution cabinet in the basement, both circuits use ZRYJV22-4x150mm2 cables, and the line m1 is 50m long.

　　After being distributed by the power distribution cabinet, they are led to the fan and emergency lighting. For emergency lighting lines, trunk type + radiation type power supply is used, two trunk lines use NHYJV cables, the specification is 4x35+1x16mm2, the line m2 is 100m long, each four floors is equipped with an emergency dual power switch box, and the roof computer room lighting is separately equipped with a pair of power switch boxes , Adopt the main line T connection to connect with the power supply main line.

　　The dual power switch box circuit of the roof machine room includes elevator shaft lighting, machine room lighting, machine room sockets, elevator shaft sockets, aviation obstruction lights and other circuits. The elevator shaft lighting circuit uses 220/36V (capacity 500VA) transformers to supply power. One lamp is installed within 0.5 meters of the low point, with an odd-numbered layer in the middle, a total of 18 lamps. The lighting adopts Philips compact energy-saving lamps, the power is 13W, the luminous flux is 900, the power factor after compensation is 0.9, and the lighting power distribution uses two BV10mm2 wires. The line m3 is 96m long.

　　The protection of the elevator shaft lighting distribution circuit should have overload protection, short circuit protection, and should avoid the starting current of the lamps.

　　When a short circuit occurs at the end of the line of this project, there are seven impedance components in the loop, including high-voltage system, 10/0.4kV transformer, low-voltage bus, low-voltage cable m1, low-voltage cable m2, 220/36V transformer, and low-voltage wire m3. According to the data in Tables 4-22~25 on pages 155~159 of the "Industrial and Building Power Distribution Design Manual" Third Edition, the impedance of the single-phase L-N circuit of each component can be calculated, and then the short-circuit current can be calculated. After calculation, the short-circuit current is, Id=105.2A.

　　The protection of the elevator shaft lighting distribution circuit should meet the following requirements:

　　1) The setting current of the long-time delay release of the low-voltage circuit breaker for lighting should be greater than the calculated current of the circuit. ,

　　2) The setting current of the instantaneous overcurrent release of the low-voltage circuit breaker for lighting should be 4~7 times greater than the calculated current of the circuit.

　　3) In order to ensure the sensitivity of the circuit breaker, the setting current of the instantaneous overcurrent release of the circuit breaker should be less than 1/1.3 times of the small short-circuit current at the end of the line.

　　For this project (18 sets of lamps), the circuit calculated current IB is IB=P/Ucosφ=18x13/(36x0.9)=7.2A. Therefore, I zd1≥1.1·7.2=7.9A, initially I zd1=16A; the formula for calculating the setting current of the instantaneous overcurrent release of the circuit breaker is: I d /1.3≥I zd3≥Kzd3·IB, that is: 105.2/1.3 ≥I zd3≥6·7.2, that is, 80.92≥I zd3≥43.2.

　　Select TCL miniature circuit breaker with B characteristic curve, short-circuit tripping action current 3~5In, small action current I zd3=3x16=48>43.2, to meet the requirements, large action current I zd3=5x16=80<81.31, to meet the requirements.

　　If the power factor of the lamp is low, such as 0.8, the calculated current of the line is IB=8.1A, I zd3=48<8.1x6=48.6, no matter how you adjust it, it is difficult for the miniature circuit breaker to avoid six times the starting current of the lamp .

　　If you choose a general type C circuit breaker, the operating current is 5-10 In, and the large operating current I zd3=10x16=180>81.31, which does not meet the requirements. Even if the rated current of the circuit breaker is reduced to 10A, I zd3=10x10=100>81.31, which still does not meet the requirements.

　　If two BV6mm2 wires are used for the main power distribution of the lamp, the loop resistance will increase by more than 60%. Since the short-circuit current will be reduced a lot, the circuit breaker operating current will not be able to guarantee the sensitivity and avoid the lamp starting current.

　　The above discussion is for miniature circuit breakers. If a molded case circuit breaker is selected, it is of course much easier because the instantaneous multiple can be adjusted, but it is obviously wasteful to use a molded case circuit breaker here.

　　Concluding remarks

　　For long-distance power supply lines, due to the large resistance and small single-phase short-circuit current, full attention must be paid to the verification of the circuit breaker's sensitivity. When using a low-voltage circuit breaker, the line short-circuit sensitivity is closely related to the line short-circuit current and the circuit breaker's setting current. If the cable cross-sectional area is too small, the switch setting current is inappropriate, and it may not be enough to make it operate and fail to protect.

　　If the cross-sectional area of the wire can be increased, the wire resistance can be effectively reduced, the short-circuit current can be increased, and the short-circuit protection can be facilitated, and the voltage loss can be reduced.

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Selection Of Switch For Lighting Circuit Of Elevator Shaft

电梯井道照明线路开关的选择

Selection Of Switch For Lighting Circuit Of Elevator Shaft

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