Optimization of Power Plant for Telecom Sector Based on Embedded System

Modern Telecom Sector is eventually facing exceptionally tough challenges because of continuous and unexpected increase in power density requirement for the communicating machinery and equipment. To fulfil the power requirements for the equipment, a significant architecture and an optimal technique must be introduced. In this paper, a microcontroller-based optimization use of power-density has been carried out. Meeting above requirements, various equipment and electronic devices are employed. We have designed a microcontroller-based system via PROTEUS Virtual System Modeling to acquire efficient and effective results. The main focus of our work is to supply the power to Telecom equipment in meantime. The power is feeding on batteries and DG (Diesel Generator) set, depending on the condition of the power requirements. The changeover operations are performed by different relays, which are dully programmed via a microcontroller in Keil software. The power capacity of Telecom ((Telecommunication) equipment is ranged from 39-48 Volts DC. The rectification process is done by switch mode rectifiers instead of linear rectifiers. Because the switch-mode rectifier technology has brought fabulous improvements in power density as compared to linear rectifiers. This is done via simulation of the smart switch in PROTEUS software. The outcomes of the proposed system are cost-effective in terms of fuel consumption of DG.


INTRODUCTION
is impossible to avoid power shortages. Because of this, not only the economic growth and commercial Sector of our country is badly affected, but Telecom sector is one of the major victim. So, an alternate technique, a standby power system is introduced to overcome this issue as given in [1][2][3][4][5].
In [1], authors have proposed a simple energy conversion system based on the fuel cell to supply energy for Telecom equipment. Their system has curtailed significant operation and maintenance cost of Telecom machinery and equipment. In addition, they also presented a closed loop and a controller with a genetic algorithm to perform voltage regulation at the base transceiver station for the power conditioning. That system was simulated in MATLAB/Simulink software.
In [2], authors have also worked on energy conversion and voltage regulation by proposing multicell converterbased approach.
In [3], authors have proposed some effective approaches like cost-effective and implementation of change-overs for the optimization of the system. By employing these approaches, the system will meet at high ranks. The costeffective approach can only be made possible by applying different techniques of implementing changeovers to the system, like manually operated changeover system and automatic changeover system. These changeover systems can be operated by automatic transfer switch or electromechanical relays. EMR (Electromechanical Relays) are also used for the security and safety of electrical system by measuring the electrical parameters such as, current, voltage and frequency. Then the measured values are sent at remote stations by GSM (Global System for Mobile Communication) network [8].
The relays will be activated automatically whenever above electrical parameters go beyond the thresholds. A circuit breaker is operated with that relay, which turns-off the whole circuitry.
Another mechanism for shutting down the whole unit is via radio frequency [11]. This technique is very useful in case of a rapid increase in current, voltage and temperature of the system. So far, the system is predicted from rapid rise of electrical and environmental parameters.
For continuous measurement of electrical parameters, viz. voltage, current, frequency generation, the speed of the turbine, etc., embedded systems are now widely used in Telecom Sector [12]. For the provision of adequate energy to the system from storage devices such as batter ies and super-capacitors, energy conversion methods have been introduced in [7]. In this system, the main intention is to provide a prescribed active and reactive energy to the system. Their system is very useful for avoiding the high charge and overcharge states of the batteries, with an aid of a dedicated control system. In [9], a microcontroller-based management scheme has been presented to monitor the low voltages for battery operated systems. The designed system has features of optimized usage of energy resources, reduction of cent percent operation of DG sets to curtail maintenance cost, reduction of fuel expenditures, and elimination of a human interference.
Telecom power plants conventionally consist of grid, DGs, backup power system, rectifiers and switches [21]. In [22][23], a microgrid based Telecom power plant are designed to provide uninterrupted power to Telecom equipment.
Mostly, batteries and super capacitors are used as a backup power system. For the provision of a continuous power supply, UPS (Uninterruptible Power Supply) are also incorporated [14][15].
Our objectives are as under: Ensure smooth/uninterrupted functioning of Telecom services (ii) To reduce the cent percent operation of DG to curtail the fuel expenditure.
(iii) Optimal utilization of battery banks within safe limits.
(iv) To reduce the human interferences by proposing a smart switch.
The paper organization is: section II covers the problem statement, quoted from early presented work regarding changeover system and techniques. Section III is all about Telecom power plant, in which power requirements and considerations are described. Section IV illustrates the complete system design, software and operation scenario.
Experimental results are mentioned in section V.
Conclusion is given in section VI.

PROBLEM STATEMENT
Standby power system is the prime requirement for the industrial, comsmercial, Telecom and domestic electrical power systems. The load, which is directly connected to the grid power must be backed up with any source which is capable to run that electrical power system continuously.
In addition, there must be a system which can transfer the electrical load without any trouble; this can be done by monitoring power plants as suggested in [13]. For this, smart switches are widely used to switch the load from grid power to the backup power system for the smooth operations and self-protection [18]. These smart

Manual Changeover Switch Box
The main task of manual changeover switch box is to isolate the sources between public supply and generator [3,19]. The changeover is operated manually by a human when the power becomes fail and the same is restored manually when power is restored. Performing this task, there is a substantial risk of electrical shocks and spars, as well as a lot of noise, are also present. Beside this, other limitations of manual changeover could be highly laborious to operate, high operation and maintenance cost, chances of damage and the time consumption as well.

Electromechanical Relays Based Automatic Changeover System
A relay; it is a type of a switch that works on the principle of electromagnetic and activated whenever its inputs are varied, and desired output will be achieved. There are two types of relays used commonly, the normally open switch and normally closed switch [3,20]. Nowadays, the EMRs are used in the electronic circuitry with many other

Optimization of Power Plant for Telecom Sector ased on Embedded System
devices to perform automatic changeover operation. An automatic system based on the electromechanical relay is shown in Fig. 1. In Fig. 1, EMR is used to oppose the return flow of AC (Alternating Current) signals into the electronically controlled devices.
The automated changeover switching system is superior to manual changeover switching system, because, it is faster, reliable, automatic, but despite various advantages, there are some hurdles yet, that are described below [3]:

Changeover with Automatic Transfer Switch
An automatic transfer switch is also used in the changeover system [20][21], this observes the AC voltage failure conditions coming from a power distribution company like HESCO (Hyderabad Electric Supply Company) in Pakistan. The predetermined conditions are set normally when the power failure occurs from Distribution Company (i.e. main supply), then a standby system (generator) will be turned into the active state.
Meanwhile, the load will be toggled to standby system (generator) from the main supply. Whenever main power supply is restored, the load will be switched back automatically.

Optimization of Power Plant for Telecom Sector ased on Embedded System
from 120, 220, or 240V with 60Hz (Hertz) frequency, whereas 220-240V single phase AC with 50Hz frequency may also be countered with [14]. A generic architecture of power supply to Telecom equipment is depicted in Fig. 2.

Power Requirements and Consideration
While selecting a power system, the configuration of its and 200,000 hours [14]. It is observed that too many parallel rectifiers' applications increase conversion equipment failure. According to AC power engineer's viewpoint, the use of N+1 parallel redundant rectifier will make the system stable and reliable, in which N is to be kept too small so that the no of parts to be reduced and avoid the failure of rectifiers [15]. Also, you may say that, if we use many devices and machinery, then the chances of the failure of components would increase accordingly.
DC power systems that run on the configuration of 48VDC, due to their low discharge rates may utilize back up battery systems for a considerable time. The system only utilizes a bank of 24 cells in series combination and the system is applied at reasonable discharge rate.
Whereas an AC UPS system uses considerable no of cells i.e. as much as 120-240 cells in series combination and have a very short back up time of 10-20 mints due to their high discharge rate with per cell discharge voltages may be down to 1.65 V or less [14]. Due to these main differences, batteries are more reliable as back power systems than AC UPS systems.

Requirements of a Telecom Power Plant
We have concluded some major requirements of a Telecom power plant from [21][22][23]. The cost must be kept minimum while designing a Telecom power plant. It must be reliable because a break in the power supply interrupts conditions. An electrical noise of the plant must be below the specified limits.

Grid Power/Main Supply
Traditional Telecom equipment is manufactured so that they require input power as AC source with single phase, generally, the available configurations are starting from 120, 220, or 240V with 60Hz frequency, whereas 220-240V single phase AC with 50Hz frequency may also be countered with.

Diesel Generator
DG set are extensively used as both primary and standby sources of power for Telecom equipment. AC DG sets are used at stations for providing a standby power source whenever main AC power supply fall occurs.

Rectifier
Usually, the Telecom equipment requires an input power of -48VDC. These types of power systems have multiple numbers of redundant rectifiers; these rectifiers are here to convert 220/240 VAC input power to -48 VDC output power. AC power is converted into -48VDC using multiple parallel rectifiers.

Battery
On occasion of AC power supply failure or rectifier failure, the essential Telecom equipment should be supported by standby batteries for some period until the main power is restored. Batteries are charged from the output of the rectifiers. Rechargeable batteries are used as a battery bank. Critical load equipment is also powered by this source.

Smart Switch
Smart switches are now extensively employed for the switching purposes, i.e. to route the power from grid power to the backup power system or any other substitutes for the continuous operations. So far, in this paper, a smart switch system has been designed and simulated at the hardware level, which has a feature to control the system operation smoothly with the help of a microcontroller.

Telecom Equipment
A Telecom sector consists of various equipment to provide communication facility for their customers.
Telecom equipment is the set of numerous devices and cannot be enlisted. A telephone transceiver set is a very common example of Telecom equipment.

Software
In

System Operation
The simulation design of smart switch is shown in Fig. 4, there are three relays RL1, RL2, RL3. RL1 is connected to the rectifier's output 48 VDC, the output of RL1 is connected to the backup battery for charging. When grid power will go down the backup battery will be utilized by the Telecom load. Fig. 4, a comparator compares the battery voltage level. If the battery will be discharged by 45V the comparator's output will be 0V. This indicates that battery must be charged again to give the continuous power to the system. For charging of the backup battery, the microcontroller will give a command to the RL2 to start the DG-set automatically. When DG-set will be started the backup, the battery will be recharged again through the RL1. After half an hour RL1 will be disconnected from the battery and the battery strength will be measured automatically by the comparator. If the battery gets charged by the 49VDC the DG-set will be stopped with the help of RL3.

Experimental work has been performed in Nawabshah
Exchange, STR-V Region, PTCL (Pakistan

Optimization of Power Plant for Telecom Sector ased on Embedded System
In is also reduced as shown in Table 2. By comparing Tables 1-2, it is justified that the fuel consumption of DG is comparatively minimized. When batteries go down, this system starts the DG automatically and utilizes its power with help of proposed smart switch and changeover system. Table 2, different rated DG sets are also listed before installation of automatic changeover switching system.
In Table 3, operation cost of DG set is tabulated. The summary of whole results is represented in terms of a graph is shown in Fig. 5

CONCLUSIONS
The optimized power plant is very much effective in terms of the cost of operation. The cost of operation is minimized up to 40%, which can be justified from the results, described in the previous section. This proposed system has provided an uninterruptible power supply from the battery banks to the Telecom equipment with the help of smart switching system. Optimal utilization of battery banks within safe limits is also described in this paper.
The main advantage of battery banks is to provide an uninterruptible power to the Telecom equipment at the specified limits. The power requirements of Telecom equipment are the maintained to facilitate the customers of a Telecom company without formal delays. This directly impacts on the quality of service of the company, which is the core value of the company. Well, besides power requirements, protection against overload and faults were also located for the betterment of the equipment. Electrical noises were also kept below the prescribed ranges.
This work can also be extended by increasing the reliability of the battery sets and minimizing the