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INTRODUCTION
Electricity is the crucial requirement for leading a comfortable life .It is to be properly used and managed. But in our country there are places where the electricity theft is done and also no proper planning of power distribution in the country is leading to calculation problems. Also there are many statistical errors prevailing in the customer’s monthly billing process.
This idea of wireless data transmission is being proposed to reduce the human dependency to collect the monthly reading and to minimize the technical problems regarding the billing process .This also helps in obtaining the monthly electricity reading from any remote location to a centralized office through GSM. This helps in considerable reduction of power thefts as well as the average consumption of a particular locality will be known and so this helps in proper power scheduling mechanism .The idea is very economical as well as efficient .this implementation is done in the form of SMS which is very cheap now a days.
The purpose of the project is to remotely collect the energy meter reading in a flexible manner and reduce the burden in technical billing mechanism.
An energy meter is a device which is used to measures the consumption of energy of any residence or other industrial establishment. In Conventional metering system to measure electricity consumption the energy provider company hire persons who visit each house and record the meter reading manually. These meter readings are used for electricity bill calculation and this bill sent to consumer house by post. This is only a sluggish and laborious. The process of calculating the tariff in the conventional or any type depends on the power generation, transmission and distribution. The tariff is calculated on both generation and utilization. All these costs when added together constitutes the total cost of electricity which in the consumers have to share according to the quantum of electricity consumed taking into account the nature and time of use of electricity by each category of consumers.
Calculation process consists of two terms:
1. Fixed cost components:
In fixed cost we consider Cost of setting up a Power Plant, Inverter, Plant & Equipment, Personnel Employed, Raw Material Inventory, Costs that are fixed. As per recent norms fixed cost cannot be recovered fully from the consumers if the capacity is not available for generation above a certain percentage of declared capacity.
• Return on equity capital
• Taxes and Duties
• Depreciation
• Interest on loan component of capital
• Interest on working Capital
• Operation & maintenance expenses
• Employment Cost
• Insurance Premium Payable
• Costs arising out of Foreign Exchange Rate Variation (FERV)
• Bad Debts
2. Variable cost components:
In variable cost we consider Cost of generating the quantum of electrical energy and cover the fuel costs for generating this quantum of electricity. The Fuel in a coal fired Thermal Power Station is coal (Primary fuel) and Oil (Secondary fuel).
• Cost supplied to the Power stations are graded as grade A, B, C, D, E, F and G according to the heat value of the particular “quality of the coal”. These heat values an expressed in Useful Heat Value (UHV). GCV of particular grade of coal is higher than its useful heat value or UHV and we also consider Auxiliary consumption and specific oil consumption.
In Conventionally metering system people try to manipulate meter reading by adoption various corrupt practices such as current reversal or CT reverse tampers, partial earth fault condition, bypass meter, magnetic interference etc . There is a stark amount of revenue loss being incurred by our country. This metering system becomes very difficult especially in rainy season. If any consumer did not pay the bill, the electricity worker needs to go to their houses to disconnect the power supply. In Power line communication ZIGBEE technology also use for meter reading. The stability and reliability of meter reading data are low in power line communication because the carrier wave signal (power/telephone line) is very easily disturbed by noise.
[1]. The ZIGBEE devices are extremely limited in resources including processing, memory, and power, short operating range.
[2]. GSM based automatic meter reading system is a succor.
AMR eliminates any possibility of electricity theft. Automatic meter reading (AMR) system is an effective way of data collection, that allow substantial saving through “the reduction of meter read, greater accuracy, allow frequent reading, improved billing, reduced tempering. It provides better customer services, by sending alert of power cuts and consummation updates.” AMR is the technology for remote monitoring and to control domestic energy meter and reduces current pilfering. Network communication technology enables energy Provider Company to read the meter reading regularly without the person visiting each house by using GSM communication technology. AMR system is very useful for remote area or small villages which are not connected by any means of transport such as an island or remote precinct. This GSM based data collection system can be very swift, accurate and efficient.
In GSM Technology, after a predefined time, the no of units consumed by the consumer will be transmitted to main super computer, with consumer code no within the specified time given in the microcontroller. This is achieved by sending the SMS to main server of service provider. One dedicated mobile will be interfaced to the PC of service provider, which will go on receiving SMS from different users. This will result in, no need of person visiting the place and noting down the readings, which then will be passed to the operator. Thus automatic meter reading helps the consumer, the energy services provider to access the latest and accurate information from the metering devices and provides saving in time, man power and helps in efficient energy management. The major advantage of this system is making use of GSM network which helps for a wireless transmission, when compared to RF module. RF network is used for only to a certain distance and cannot transmit the data due to high noise occurrence.
. MICRO CONTROLLER
3.1 INTRODUCTION:
A microcontroller (sometimes abbreviated µC, µ C or MCU) is a small computer on a single integrated circuit containing a processor core, memory and programmable input/ output peripherals. Program memory is in the form of both erasable and non erasable forms and often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.
Intel 8051 and 8052 are members of Intel MCS-51 family of 8-bit microcontrollers. In addition to on-chip clock oscillator, 2 16-bit timers, 4 I/O ports and a serial port, all 8051 and 8052 chips have 128 bytes of RAM and 4 KB masked ROM. If necessary, 8051 memory can be expanded up to 128 KB by adding up to 64 KB of external program and data memory. Here we are using the micro controller AT89C52 due to its extra features when compared to 8051, some of them are it provides more amount of Flash memory and RAM memory by which more amount of data can be stored and hence can be used for various applications.
3.2 FEATURES OF AT89C52:
• 8K Bytes of In-System Reprogrammable Flash Memory
• Endurance: 1,000 Write/Erase Cycles
• Fully Static Operation: 0 Hz to 24 MHz
• Three-level Program Memory Lock
• 256 x 8-bit Internal RAM
• 32 Programmable I/O Lines
• Three 16-bit Timer/Counters
• Eight Interrupt Sources
• Programmable Serial Channel
• Low-power , Idle and Power-down Modes
VCC: Supply voltage.
GND: Ground.
Port 0: Port 0 is an 8-bit open drain bi-directional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high impedance inputs. Port 0 can also be configured to be the multiplexed low order address/data bus during accesses to external program and data memory.
Port 1: Port 1 is an 8-bit bi-directional I/O port with internal pull ups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pull ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pull ups.
Port Pin Alternate Functions
P1.0 T2 (external count input to Timer/Counter 2), clock-out P1.1 T2EX (Timer/Counter 2 capture/reload trigger and direction control)
Port 2: Port 2 is an 8-bit bi-directional I/O port with internal pull ups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pull ups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pull ups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that uses 16-bit addresses (MOVX @ DPTR).
Port 3: Port 3 is an 8-bit bi-directional I/O port with internal pull ups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the internal pull ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pull ups.
Port Pin Alternate Functions:
P3.0 RXD (serial input port), P3.1 TXD (serial output port), P3.2 INT0 (external interrupt 0), P3.3 INT1 (external interrupt 1), P3.4 T0 (timer 0 external input), P3.5 T1 (timer 1 external input), P3.6 WR (external data memory write strobe), P3.7 RD (external data memory read strobe).
RST: Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device.
ALE/PROG: Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. This pin is also the program pulse input (PROG) during Flash programming. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external
PSEN: Program Store Enable is the read strobe to external program memory. When the AT89C52 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory.
EA/VPP: External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. This pin also receives the 12-volt programming enable voltage (VPP) during Flash programming when 12-volt programming is selected.
XTAL1 & XTAL2: Input to the inverting oscillator amplifier, internal clock operating circuit. Output from the inverting oscillator amplifier.
3.4 SPECIAL FUNCTION REGISTERS:
SP (Stack Pointer, Address 81h): This is the stack pointer of the microcontroller. This SFR indicates where the next value to be taken from the stack will be read from in Internal RAM. If you push a value onto the stack, the value will be written to the address of SP + 1. This SFR is modified by all instructions which modify the stack, such as PUSH, POP, and LCALL, RET, RETI, and whenever interrupts are provoked by the microcontroller.
DPL/DPH (Data Pointer Low/High, Addresses 82h/83h): The SFRs DPL and DPH work together to represent a 16-bit value called the Data Pointer. The data pointer is used in operations regarding external RAM and some instructions involving code memory. Since it is an unsigned two-byte integer value, it can represent values from 0000h to FFh (0 through 65,535 decimal).
PCON (Power Control, Addresses 87h): The Power Control SFR is used to control the power control modes. These modes of operation are controlled through PCON. Additionally, one of the bits in PCON is used to double the effective baud rate of the serial port.
TCON (Timer Control, Addresses 88h, Bit-Addressable): The Timer Control SFR is used to configure and modify the way in which the 8051's two timers operate. This SFR controls whether each of the two timers is running or stopped and contains a flag to indicate that each timer has overflowed. Additionally, some non-timer related bits are located in the TCON SFR. These bits are used to configure the way in which the external interrupts are activated.
TMOD (Timer Mode, Addresses 89h): The Timer Mode SFR is used to configure the mode of operation of each of the two timers. Using this SFR your program may configure each timer to be a 16-bit timer, an 8-bit auto reload timer, a 13-bit timer, or two separate timers. Additionally, you may configure the timers to only count when an external pin is activated or to count "events" that are indicated on an external pin.
TL0/TH0 (Timer 0 Low/High, Addresses 8Ah/8Ch): These two SFRs, taken together, represent timer 0. Their exact behavior depends on how the timer is configured in the TMOD SFR; however, these timers always count up. What is configurable is how and when they increment in value.
TL1/TH1 (Timer 1 Low/High, Addresses 8Bh/8Dh):These two SFRs, taken together, represent timer 1. Their exact behavior depends on how the timer is configured in the TMOD SFR; however, these timers always count up. What is configurable is how and when they increment in value.
SCON (Serial Control, Addresses 98h, Bit-Addressable): The Serial Control SFR is used to configure the behavior of the 8051's on-board serial port. This SFR controls the baud rate of the serial port, whether the serial port is activated to receive data, and also contains flags that are set when a byte is successfully sent or received.
SBUF (Serial Control, Addresses 99h): The Serial Buffer SFR is used to send and receive data via the on-board serial port. Any value written to SBUF will be sent out the serial port's TXD pin. Likewise, any value which the 8051 receives via the serial port's RXD pin will be delivered to the user program via SBUF. In other words, SBUF serves as the output port when written to and as an input port when read from.
IE (Interrupt Enable, Addresses A8h):The Interrupt Enable SFR is used to enable and disable specific interrupts. The low 7 bits of the SFR are used to enable/disable the specific interrupts, where as the highest bit is used to enable or disable ALL interrupts, regardless of whether an individual interrupt is enabled by setting a lower bit.
IP (Interrupt Priority, Addresses B8h, Bit-Addressable): The Interrupt Priority SFR is used to specify the relative priority of each interrupt. On the 8051, an interrupt may either be of low (0) priority or high (1) priority. An interrupt may only interrupt interrupts of lower priority.
PSW (Program Status Word, Addresses D0h, Bit-Addressable): The Program Status Word is used to store a number of important bits that are set and cleared by the instructions. The PSW SFR contains the carry flag, the auxiliary carry flag, the overflow flag, and the parity flag. Additionally, the PSW register contains the register bank select flags which are used to select which of the "R" register banks are currently selected.
ACC (Accumulator, Addresses E0h, Bit-Addressable): The Accumulator is one of the most-used SFRs since it is involved in so many instructions. The Accumulator resides as an SFR at E0h.
GSM MODEM
4.1 INTRODUCTION:
GSM has been the backbone of the phenomenal success of mobile communication in the previous decade. Now at the dawn of true broadband services, GSM continues to evolve to meet new demands. GSM is an open, non proprietary system with international roaming capability.
GSM was originally known as Grouped Special Mobile but nowadays it is commonly referred as Global System for Mobile Communication. It is a set of standards developed by the European Telecommunications Standards Institute (ETSI) to describe technologies used for second generation digital communications, commonly referred as 2G technologies. It was developed as a replacement to the first generation analog communications. It originally described a digital circuit switched network optimized for full duplex voice communications.
The standard was expanded over time to include first circuit switched data transfer, then packet data transport via GPRS (General Packet Radio Service). Packet data transmission speed was later increased with the help of EDGE (Enhanced Data Rate for GSM evolution) technology. The GSM standard is succeeded by third generation (3G) UMTS standard developed by the 3GPP.
4.2 TECHNICAL DETAILS:
GSM is a cellular network which means that compatible devices connect to it by searching for cells in the immediate vicinity. There are five different cell sizes in a GSM network viz. Macro, Micro, pico, femto and umbrella cells. The coverage area of each cell varies according to the implementation environment.
• mast or building above roof top level.
• Micro cells are those in which base station is installed below the average roof top level. They are typically used in urban areas.
• Pico cells are the cells whose coverage area is a few dozen meters in diameter and are mainly used indoors.
• Femto cells are cells designed for use in residential or small business environment and connect to the service provider’s network via a broadband internet connection.
• Umbrella cells are used to cover shadowed reasons of smaller cells and fill in gaps in coverage between those cells.
COMPONENTS
6.1 POWER SUPPLY COMPONENTS:
This unit consists of a transformer which steps down the 230V AC into the required 12V and then the full wave rectifier rectifies the AC into DC and the voltage regulator regulates the output to exact value.
The current transformer and voltage transformer are used to calculate the power consumed by the load .It almost acts as energy meter by calculating the power consumed by the load.
In alternating current the electron flow is alternate, i.e. the electron flow increases to maximum in one direction, decreases back to zero. It then increases in the other direction and then decreases to zero again. Direct current flows in one direction only. Rectifier converts alternating current to flow in one direction only. This unidirectional property of the diode is useful for rectification. Double diodes arranged back-to-back might act as full wave rectifiers as they may allow the electron flow during both positive and negative half cycles. Four diodes can be arranged to make a full wave bridge rectifier. Different types of filter circuits are used to smooth out the pulsations in amplitude of the output voltage from a rectifier. The property of capacitor to oppose any change in the voltage applied across them by storing energy in the electric field of the capacitor and of inductors to oppose any change in the current flowing through them by storing energy in the magnetic field of coil may be utilized.
Here in this project we have used voltage transformer to give supply voltage to all the components involved in the circuit and to measure the voltage used by the load, also we have used a current transformer to measure the current flow in the circuit by means of which we can calculate the power used by the load.
6.1(A) CURRENT TRANSFORMER:
A current transformer is defined as "as an instrument transformer in which the Secondary current is substantially proportional to the primary current (under normal conditions of operation) and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connections." This highlights the accuracy requirement of the current transformer but also important is the isolating function, which means no matter what the system voltage the secondary circuit need be insulated only for allow voltage. The current transformer works on the principle of variable flux. In the "ideal" Current transformer, secondary current would be exactly equal (when multiplied by the turns ratio) and opposite to the primary current. But, as in the voltage transformer, some of the primary current or the primary ampere-turns is utilized for magnetizing the core, thus leaving less than the actual primary ampere turns to be "transformed" into the secondary ampere-turns. This naturally introduces an error in the transformation. The error is classified into two-the current or ratio error and the phase error.
RECTIFICATION:
Rectification is a process of rendering an alternating current or voltage into a unidirectional one. The component used for rectification is called ‘Rectifier’. A rectifier permits current to flow only during the positive half cycles of the applied AC voltage by eliminating the negative half cycles or alternations of the applied AC voltage. Thus pulsating DC is obtained. To obtain smooth DC power, additional filter circuits are required.
A diode can be used as rectifier. There are various types of diodes. But, semiconductor diodes are very popularly used as rectifiers. A semiconductor diode is a solid-state device consisting of two elements is being an electron emitter or cathode, the other an electron collector or anode. Since electrons in a semiconductor diode can flow in one direction only-from emitter to collector- the diode provides the unilateral conduction necessary for rectification.