Shulou(Shulou.com)11/24 Report--

The serious problem of base station power outage communication base stations will face AC power outage, so they will be equipped with batteries for a rainy day, and the battery as a backup power supply time is limited. If the alternating current fails to call in time during the discharge of the battery, it will face two serious problems:

1. The consequence of power outage of important main equipment is very serious. if some important main equipment in the base station is powered off, it will cause serious consequences. for example, if the power outage of the transmission equipment, it will affect the transmission ring network and lead to the interruption of base station transmission in most areas. causing more serious communication failures.

2. Battery overdischarge does great damage to battery life. Battery overdischarge does great damage to battery life, and it is irreversible. The following table shows the relationship between the discharge depth and the life of a storage battery.

Discharge depth

(%)

Designed number of charge and discharge

(lifespan)

five

10000

twenty

2000

fifty

eight hundred

one hundred

three hundred and fifty

As can be seen from the above table, the discharge depth of the battery is too deep, which will seriously affect its service life. The price of the battery is high, so overdischarge of the battery should be avoided.

Therefore, if the base station AC power outage, in the battery power supply process, the AC power failed to call in time, the base station equipment power down, resulting in the inevitable loss of business. We have no way to avoid business losses, but we can reduce business losses and damage to batteries through scientific management of batteries.

As a result, the primary power-down and secondary power-off functions of the base station communication power supply came into being.

What is the primary and secondary power down base station main equipment can be divided into: important primary equipment (such as: transmission equipment) and secondary primary equipment according to importance. When there is a power outage, there is only one way to ensure that the battery can power the important main equipment for longer: cut off the power supply to the secondary main equipment.

In the process of battery power supply, the action of cutting off the power supply to the secondary primary equipment for the first time is called a power down. What people say is: the battery is not enough! Power off all the relatively unimportant main equipment. Because it is the first time, so call a power down!

So, what is a secondary power outage?

After a power outage, the battery continues to discharge, but sometimes, the battery discharges to close to the discharge depth warning line, and the alternating current has not come yet!

In order to ensure that the battery does not cause great damage due to overdischarge, the communication power supply cuts off the power supply to the important main equipment for the second time. What people say is: the battery will not play with you, and all the power will be cut off!

So, how is the primary power-off and the secondary power-off realized in the power system?

The implementation mechanism of primary power outage and secondary power outage. First of all, let's look at two features:

1. Battery characteristics during the discharge of the battery, the terminal voltage of the battery will decrease according to the rules, so the remaining capacity of the battery can be roughly known by measuring the terminal voltage of the battery. Using this feature, the CSU (centralized management unit) of the communication power supply can roughly understand the amount of battery power.

2. DC contactor characteristics DC contactor is a kind of electronic device, which has a characteristic: when the DC contactor is energized, its state (closed or disconnected) will change. Before power up, the DC contactor usually closes, as shown in the following figure.

After electrification, the coil has a current flow to produce a magnetic field, and the static iron core attracts the moving iron core and drives the moving contact to close with the normally open contact. The DC contactor state changes from closing to disconnecting, as shown in the following illustration.

Taking advantage of this characteristic, DC contactors are often used as automatic switches in DC circuits.

The communication power supply uses the above two characteristics to realize the primary power-off and the secondary power-off, and the implementation steps are as follows:

The main results are as follows: 1. The CSU of the communication power supply detects the battery terminal voltage in real time, the two contactors of the primary and secondary power shunt are closed, and the primary and secondary power supply is normal.

2. After the power outage, the battery discharges. When the terminal voltage of the battery is lower than the primary voltage value (which can be set in CSU), the CSU disconnects the power supply to the primary power shunt contactor. Once the power-off contactor is disconnected, all the secondary main equipment is powered off, and a power-down is completed.

3. After the primary power off, the battery continues to discharge. When the terminal voltage of the battery is lower than the secondary voltage value (which can be set in CSU), the CSU disconnects the power supply to the secondary power shunt contactor. The secondary power-off contactor is disconnected, all the important main equipment is off, and the first power-off is completed.

Do you think you have mastered the functions of primary power-off and secondary power-off? But if someone tells you that I have tested that the voltage at the end of the battery has not reached a power-down voltage, I have done a power-off for Shenma? Do you think there must be something wrong with the system?

The answer is no, because you haven't mastered the advanced knowledge of electrification. In fact, the terminal voltage of the battery is not the only primary and secondary power-down condition.

Some people think that the trigger condition of power-down voltage is not intuitive enough, and want to use the more intuitive parameters such as battery remaining capacity or power outage time as power-off trigger conditions.

The so-called remaining capacity of the battery refers to the percentage of remaining power in the process of battery discharge. For example, 60% means that the current battery has 60% left.

The so-called blackout time refers to the accumulated time after the AC power outage, for example: 60 minutes, refers to the current AC power outage for 60 minutes.

It should be noted that both the remaining capacity of the battery and the outage time constitute the power-down trigger condition together with the power-down voltage. In other words, when one of the remaining capacity / outage time and power-down voltage of the battery reaches the power-down condition, the primary power-off / secondary power-off is triggered.

How to set the primary power-off and the second power-off can be seen from the previous article. CSU determines whether to issue the primary power-off and secondary power-off instructions by detecting the battery terminal voltage. Then, there must be some parameters related to primary power-off and secondary power-off in CSU to support the judgment of CSU. Indeed, let's take a certain CSU of ZTE Corporation as an example to describe the parameters related to primary and secondary power outages (see table below).

Parameter name

Default value

Value range

Description

Power-off mode

Battery voltage

Battery voltage

Power outage time

Battery remaining capacity

Prohibited

The power-off mode determines the conditions for the power-off judgment of the system. Due to possible errors in outage time and battery capacity, the battery voltage will take effect no matter which power-down mode is chosen. For example, when the remaining capacity of the battery is greater than the "primary power-down capacity", the battery voltage is less than the "primary power-down voltage", and a power-down is still performed. The load is powered on at one time

Allow

Prohibit / allow

Whether the system is allowed to power off the load once according to the power-down mode.

Load secondary power-off enable

Prohibited

Prohibit / allow

Whether the system is allowed to power off the load for the second time according to the power-off mode.

Primary power-down voltage

45.0 V

38.0 VFT 45.0 V

When the "power down mode" is set to "battery voltage" and "load once power down enable" is set to "allow", when the battery terminal voltage is less than this parameter, and the battery is discharging or the system is power off, a power down will be carried out.

Secondary power-down voltage

44.0 V

38.0 VFT 45.0 V

When the "power down mode" is set to "battery voltage" and "load secondary power off enable" is set to "allow", when the battery terminal voltage is less than this parameter, and the battery is discharging or the system is power off, the secondary power off will be carried out.

One power-off time

300 Min

3 Min~1000 Min

When the "power down mode" is set to "outage time" and "load once power down enable" is set to "allowed", when the battery terminal voltage is less than "primary power off voltage" or the power outage time is greater than "one power off time", then a power off will be carried out.

Secondary power-off time

600 Min

3 Min~1000 Min

When the "power down mode" is set to "outage time" and "load secondary power off enable" is set to "allowed", when the battery terminal voltage is less than the "secondary power off voltage" or the power outage time is greater than the "secondary power off time", then the secondary power off is carried out.

Primary power-down capacity

0.6C10

0.4C10 ~ 0.64C10

When the "power down mode" is set to "battery remaining capacity" and "load primary power-down enable" is set to "allowed", when the battery terminal voltage is less than "primary power-down voltage" or the minimum effective battery capacity is less than "primary power-down capacity", and the battery is discharging or the system is powered off, a power down is carried out.

Secondary capacity

0.6C10

0.4C10 ~ 0.64C10

When the "power-down mode" is set to "battery remaining capacity" and "load secondary power-down enable" is set to "allow", when the battery terminal voltage is less than "secondary power-down voltage" or the minimum effective battery capacity is less than "secondary power-off capacity", and the battery is discharging or the system is power off, the secondary power off is carried out.

By setting the above parameters, you can set the primary power-off and secondary power-off functions. For example, if we want to set the battery terminal voltage lower than 45.2V to power off once, as long as we make the following settings.

Parameter name

Battery voltage in power mode at set value

The load is powered on at one time

Allow

Primary power-down voltage

45.2 V concluding remarks after the AC power outage, if you can not call in time, it will cause business loss and battery damage. Therefore, for base stations with frequent power outages, there are the following suggestions:

It is recommended to configure a battery with sufficient capacity to ensure that the main equipment will not be cut off before the AC call.

It is recommended to be equipped with a generator, which can be used to power the communication power supply after a power outage in the city.

It is recommended to make a good configuration of primary power-off and secondary power-off to minimize the loss as far as possible after the AC power outage.

This article comes from the official account of Wechat: ZTE documents (ID:ztedoc)

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