【 Weak current College 】 front-end design and maintenance of the UPS power 】

In recent years, the cable TV industry in China is developing rapidly, the audience with a variety of television programmes, enrich our cultural life, especially CNN newly developed versatile value-added services, data services, the more our country informatization has injected new vitality, therefore, to ensure the safe operation of cable television and broadcast quality is essential. CATV is the heart of the system, in order to ensure system stability, the heart work required to use front end UPS uninterruptible power supply. UPS power solves power, voltage, power surge, settlement, decrease of oscillation, power interference, power surge, power fluctuations, switching transients and harmonic distortion, etc. from the mains power supply quality difference on the front-end device hazards.

First, how to design a UPS power supply system

1, UPS does not end the power between works

UPS (uninterruptedpowersupply) power consists of two parts and batteries, according to working methods can be divided into off-line and on-line. Off line ups in normal power supply, power supply 220V 50 Hz AC bypass channel supply power directly to the load, the host of the inverter does not work, just in the city electricity have a power, battery, inverter-driven load. Therefore it is essential to the power quality has not changed.

While the online UPS is different, in the normal power supply, it first AC into DC, and then make the pulse width modulation, filtering, and then restart the DC into AC power supply to the load; once the mains, immediately replaced by battery power inverter to load; therefore, online UPS output is totally isolated power systems with the city of pure sine wave power, greatly improved the quality of electricity supply, protecting load safe and effective work.
　　　　
2. UPS rated output capacity of the choice

First calculate the front-end load power, to ensure that the UPS system efficient and as much as possible to extend the service life of UPS, a general load power should meet UPS power rating of 60-70%. For example, we need uninterrupted power device with satellite receiver, modulator, mixer, light emitting from the computer and network switching, statistical power to 4500VA, therefore we select 4500 ÷ 75% ≈ 6428VA, so I chose 6500W online-host.

3. calculation of the battery operating time

Battery basic parameters: voltage (2V, 6V, 12V, etc.), capacity (65AH, 100AH)

In practice, we summarize the following formula calculates the battery operating time:

Battery capacity × voltage/host rating × 0.75 (power factor) = full time battery operating time

For example our UPS system, host rated power 6500W, three battery Cabinet 30 block lead-acid battery, capacity each voltage 12V 100AH.

So the battery voltage = 12V× 10 = 120V

Battery pack capacity = 3 = 300AH 100AH×

The system when the battery is full working time: 300AH×120V/6500W× 0.75 = 7.4 hours

Description of the system in the event of the battery at least can work 7.4 hours.

To actually load power calculation:

300AH×120V/4500W = 8 hours

Our front end UPS system loses power, up to 8 hours, insist on this result thanks to our multiple discharge experiments proved correct. the above formula if backstepping, according to the local situation, determine battery required hours of work, you can determine the required battery capacity and voltage.

4. wiring options

Reasonable choice wiring is very important that the wire diameter is too small, the current is too large, easy to heat and fire; diameter is too coarse, the wastage. According to the electrical characteristics of metal wire, stranded copper wire General capacity to 6A/mm, wire capacity 4A/mm, determine host power, you can reference the table select wiring and air switch.

5. Select brand

When you purchase your UPS power, should mainly take into account the following factors: the input voltage, output voltage range, output frequency range, the bypass switch and anti-inverter zero or surge, interference and harmonic distortion of capacity, in addition, the after-sales service is also very important. Large practice has proved that if UPS output zero line on the ground of "noise" potential too high can cause computing network data communication error rate increases, if you use high-frequency model, because high-frequency radiation, it will have an impact on computer network, so the selection of these issues should be taken into account.

2. UPS system maintenance

1, host of maintenance and notes

UPS host generally intelligent, environmental temperature is not high, but require indoor cleaning, dust when wet can cause host work disorder; host of parameters in use cannot change; in the case of a power outage, avoid start UPS power load, you should turn off the UPS load, and then open the load after startup, or you will have a lot of load current and supply current moment caused UPS power, serious damage when overload converter; you cannot let UPS power often Laden or overload.

2, battery maintenance and notes

Although using a maintenance-free battery, adopted a broad term certain maintenance or necessary. First of all it requirements to the ambient temperature is high, the work environment General requirements in 20 ℃-25 ℃, below 15 ° c,Its discharge capacity drops, 1 ° c temperature reduction, its capacity drops 1%, while the temperature is too high (greater than 30 ° c) their life will be shortened; Secondly, to avoid a short circuit or depth of discharge, depth of discharge will cause the battery to increase or charging voltage is too low to cause reduced or even lost the degree of charging capacity, discharge, cycle life is shorter; third, to avoid the high current charging and discharging, this will cause the battery plate for expansive deformation, making off plate active substances, the resistance increase, decrease, life shortening capacity; fourth, due to the combination of the battery voltage is high, there is a risk of electric shock, so handling conductive joins, output line should have security; fifth, frequent power outages in the area, it is recommended that the user every other month to UPS a human power, UPS power inverter State for a period of time, preventing electrolyte precipitation to let the battery charge and discharge of maintaining good characteristics, lengthen service life; the sixth, handling batteries do not touch the pole and safe valve; the seventh, which cannot be provided, in the event of fire, carbon oxide available four fire-like; the eighth, the different size, different manufacturers, different performance battery with together, otherwise it will affect the performance of the entire set of batteries.

5. Select brand

When you purchase your UPS power, should mainly take into account the following factors: the input voltage, output voltage range, output frequency range, the bypass switch and anti-inverter zero or surge, interference and harmonic distortion of capacity, in addition, the after-sales service is also very important. Large practice has proved that if UPS output zero line on the ground of "noise" potential too high can cause computing network data communication error rate increases, if you use high-frequency model, because high-frequency radiation, it will have an impact on computer network, so the selection of these issues should be taken into account.

2. UPS system maintenance

1, host of maintenance and notes

UPS host generally intelligent, environmental temperature is not high, but require indoor cleaning, dust when wet can cause host work disorder; host of parameters in use cannot change; in the case of a power outage, avoid start UPS power load, you should turn off the UPS load, and then open the load after startup, or you will have a lot of load current and supply current moment caused UPS power, serious damage when overload converter; you cannot let UPS power often Laden or overload.

2, battery maintenance and notes

Although using a maintenance-free battery, adopted a broad term certain maintenance or necessary. First of all it requirements to the ambient temperature is high, the work environment General requirements in 20 ℃-25 ℃, below 15 ° c, its discharge capacity drops, 1 ° c temperature reduction, its capacity drops 1%, while the temperature is too high (greater than 30 ° c) their life will be shortened; Secondly, to avoid a short circuit or depth of discharge, depth of discharge will cause the battery to increase or charging voltage is too low to cause reduced or even lost the degree of charging capacity, discharge, cycle life is shorter; third, to avoid the high current charging and discharging, this will cause the battery plate for expansive deformation, making off plate active substances, the resistance increase, decrease, life shortening capacity; fourth, due to the combination of the battery voltage is high, there is a risk of electric shock, so handling conductive joins, output line should have security; fifth, frequent power outages in the area, it is recommended that the user every other month to UPS a human power, UPS power inverter State for a period of time, preventing electrolyte precipitation to let the battery charge and discharge of maintaining good characteristics, lengthen service life; the sixth, handling batteries do not touch the pole and safe valve; the seventh, which cannot be provided, in the event of fire, carbon oxide available four fire-like; the eighth, the different size, different manufacturers, different performance battery with together, otherwise it will affect the performance of the entire set of batteries.

At the same time, they should periodically check the battery, measurement, and record. Check the project include: the entire battery of floating charge voltage, single cellsfloating charge voltage, the voltage measuring single cells when the battery discharge status, otherwise the measured results are false voltage, experience is in both ends of the multimeter measured parallel to a 1-3-European female resistance wire; check if the battery is damaged, shell, cover with no leakage, surface dust and other debris, battery holder, connectors, terminals are there loose or rust, etc. Single battery voltage cannot be lower than the nominal value of 70%, judging is leakage or acid mist signs is to observe the pole for Crystal falls out, Crystal falls out proved spills or leakage are acid, concentrated mainly in the battery positive and negative terminals, allowing overflow mainly near the exhaust valve. Once found the battery voltage anomalies, physical injury, electrolyte leakage, etc. of temperature anomalies, should identify the causes and timely replacement of the defective battery.