Electrical Power Monitoring Remote Metering System

Introduction

Currently, scientific and technical research is underway around the world to transmit information through electricity transmission networks. The implementation of the federal energy saving program is associated with the introduction of modern means of accounting for electricity at all stages of its production, transmission, distribution and consumption .

The traditional measuring network with the use of laid information cables, with certain advantages, has a number of significant drawbacks: high installation costs, the need to fully finance the laying of lines and the installation of communication equipment, a low degree of vandalism and protection against data distortion.

Low-cost radio access options have low information transfer rates, with a selected frequency range, the need to increase the information power of the system encounters competition with other services. In addition, radio bands around the world prefer to leave for mobile communication systems, including wireless personal communications. The cost of GSM equipment and the absence of a continuous coverage area do not allow planning its wide implementation in our country.

It should be recognized that the underdevelopment of telecommunications infrastructure in most regions of Russia makes it necessary to choose low-voltage electric networks as the medium of data dissemination.

A number of organizations and industrial companies, both foreign and domestic, are actively working on the creation and development of PLC systems.

Currently, much attention is paid to automating the technical accounting of electricity. Automated power metering systems allow you to take into account power consumption and energy at the lowest cost of time and money.

The theme of this diploma project is the development of a device for technical accounting of electricity. The system allows you to record the amount of electricity consumed from the central control panel (CDP). Indications of the measuring instrument of power are brought in Flashpamyat from where at any moment on demand with CDP are read out and transmitted on alternating current main 220B through the Network transceiver on Kr1446khk1 base. A distinctive feature of this system is the possibility of using 220V AC networks for information transmission, which eliminates the need to lay additional communication channels, and this in turn leads to a noticeable cheaper energy metering systems.

Review

for the student's diploma project

The diploma project was completed in full accordance with the task. The development uses the latest achievements in the field of digital electronics of our profile.

Detailed analysis of SOW was carried out in the project. The operation of the entire circuit and its individual units is described in detail.

The selection of the element base for the devices was carried out, based on minimizing the overall equilibrium parameters and power consumption while maintaining its functional capabilities and technical characteristics. The chosen element base (BMK 1537HM2) provides unification in production and also to improvement of key parameters of the device.

Electrical schematic diagrams of the devices are developed taking into account the specifics of their application, the requirements of technical standards and modern trends in the production of radio equipment. The specialized software "NEVOD 4.3" and the widely distributed software package OrCAD 9.1 have been mastered.

In addition, the project contains sections dealing with environmental and safety issues, as well as a business plan.

The explanatory note and the graphic part are carefully and carefully executed.

The author showed himself as a competent professional, showed sufficient knowledge in the field of digital technology, technologies for the development and production of radio equipment.

Feasibility study and substantiation of the structural diagram of the remote energy consumption accounting system. Substantiation of power meter structural diagram

1.1 Feasibility Study

Due to the transition to a market economy, it has become necessary to improve energy management efficiency, as this is in the economic interests of electricity suppliers and consumers. One of the areas of solving this problem is accurate control and accounting of electricity. It is this direction that should provide a significant part of the total energy saving, the potential of which is more than 1/3 of the total current energy consumption.

New economic relations in energy management are manifested in the formation of a single electricity market. Based on the above, the electricity market should be a multi-component mechanism for harmonizing the economic interests of electricity suppliers and consumers.

One of the most important components of the electricity market is its tool providing which represents set of systems, devices, devices, communication channels, algorithms, etc. for control and management of energy consumption parameters. The basis for the creation and development of instrumentation is automated systems for monitoring and accounting for electricity consumption, built using PLC technology.

In 2007, the experiment was completed, the purpose of which was to practically determine the characteristics of communication channels formed on the basis of PLC technology.

PLC technology is a digital telecommunications technology that allows the use of power electrical cables and wires for information transfer instead of traditional telephone lines or radios.

The results obtained during the experiment confirmed that power cable lines allow creating communication channels based on them that provide an information transfer rate of up to 30 mbps or more.

In Ukraine, the Neptune plant and Integral LLC (Odessa) are producing and actively introducing high-frequency and low-frequency communication equipment through high-voltage power lines. In Russia JSC Shadrinsk Telephone Plant (Shadrinsk) releases the equipment of communication channels on power lines of AKST "LiniyaU"; IAC STC Kontinium (Moscow) offers an automated energy monitoring and accounting system (AIIS KUE) using low-voltage electric lines for data transmission; the Angstrom plant (Zelenograd) produces transceiver chips for transmitting data through power supply lines;

However, one cannot fail to note the factors that hamper the development of this area: inertia in solving standardization issues, as well as a significant difference between electric networks and western ones.

Implementation of the AIIS CMS data collection system enables:

Keep up-to-date accounting of electricity consumption by each network subscriber without the need for direct access to metering devices for verification of readings;

Monitoring of technical condition and detection of faulty power meters;

Eliminating the possibility of unpunished theft of electricity and other violations by end-users of electricity;

Provide the possibility of calculating for consumed electricity at several rates;

Calculate the balance of electricity released and consumed by subscribers to reduce technical and commercial losses.

Currently, there are many variants of PLC modems on the market. Consider the main ones:

EM10 is used for transmission of digital information via 220/380 V, 50 Hz power grids within one transformer substation.

EM10 can be used in multi-family residential and industrial buildings for transmitting information through the electric network from energy consumption meters of various types (electricity, heat, water, gas), for alarm and communication, for the "last mile of the Internet" - without laying special communication lines.

EM10 has the following main characteristics:

max. data transfer rate in the electrical network 2400 bps;

carrier frequency in the range up to 150 kHz ;

length of telecommunication lines - 200-500 m (depends on noise and electrical characteristics of the network);

maximum number of electromodems operating in one information network - 200 pcs.;

standard mains connection connector;

modem connection indicator to the mains;

galvanically isolated RS232 data input (connector 9 DIN) with CTS signal;

The rate of communication through the RS232 port is 4800 bps .

Programmable modem numbers for a masterslave system

possibility of modem operation in CENELEC EN standard

500651;

software majoring of information transmitted via the electrical network;

ambient temperature 0... 40 deg. C;

plastic housing (150 * 100 * 59 mm).

In a masterslave information collection system, the EM10 can be used as a master modem or slave modem.

The specialized "slave" electromodem can be quickly developed using the technical solutions used in the EM10 modem and manufactured in the necessary quantities on the basis of a special TA that determines the requirements for the design of the electromodem, for the input interface, and other customer requirements.

At the moment, the EM10 electric ship is manufactured using pilot production technology. Modem price EM10 = $250 USD.

As can be seen from the reference material, the price of such a modem is quite high.

Consider an example of a PCP1 transceiver.

The network transceiver module is based on the KP1446XK1 network transceiver chip and the KN1871E1 microcontroller (there is a modification with the Intel AT2051 microcontroller). Designed to transmit information to an AC 220V visitor. Its features:

Using frequency keying to transmit information;

Ability to select carrier frequency;

Programmable rate up to 992 bps;

Overall dimensions: 95x58mm (84.5x54.5mm - without microcontroller).

Currently, the main manufacturers of electric meters in Russia, such as MZEP, Ryazan Instrument Plant, MATZ, Frunze Plant, Elektromera, etc., have mastered the standard nomenclature of single-phase meters: single-tariff, two-tariff (with an external tariff meter) and multi-tariff (with an internal tariff meter). The accumulated positive experience of their operation, especially those made using surface installation technology, allowed a number of energy retail companies to decide on the preferential use of electronic meters. The analysis of technical solutions used in the meters of Russian enterprises allows you to make the following generalizations. As a current transmitter, as a rule, a toroidal current transformer with a closed magnetic circuit of amorphous iron is used. At the initial stage, this was the optimal solution, since it made it possible to produce high-precision single-phase meters on existing metrological equipment and the inexpensive element base that existed at that time. However, such a counter does not take into account the power consumption when feeding the load through a half-period rectifier due to saturation of the transformer magnetic circuit and therefore does not fully comply with the international standard IEC 1036. Therefore, a number of Russian manufacturers began to produce in limited quantities meters with a current transmitter based on a low-power precision shunt with a resistance of about 0.5-1 mOhm and imported power converter chips. The main technological disadvantage of the shunt is the presence of galvanic connection of input and output circuits, which requires special metrological equipment for group tests of meters, including in repair and periodic verification services. An alternative but rather complex solution is the use by some enterprises of inductive converters with an unsaturated magnetic circuit in combination with a precision integrator.

1.2 Substantiation of the structural diagram of the remote power consumption accounting system

In the draft of the new Russian standard, introduced from January 1, 2008, the requirement of correct behavior of direct switching counters at non-sinusoidal with a constant component of load currents becomes mandatory. In addition, a number of new tests are being introduced to verify accuracy in the presence of harmonics in current and voltage circuits. The counter core is the power converter integrated circuit. They use high-speed analog-to-digital information processing methods and allow them to create counters of the required accuracy class. On the Russian market there are integrated circuits of a power converter of domestic and imported production. Their parameters and functionality are largely the same, and often the choice is dictated by subjective reasons and opportunistic considerations. In this regard, I would like to pay attention to the family of inexpensive integrated circuits of the ADE7751 power converter manufactured by ANALOG DEVICE Corporation. The ADE7751 IC is a chip for high precision power meters. The technical characteristics of this IE exceed the accuracy requirements of IEC61036. The analog part of the ADE7751 consists only of analog-to-digital converters and a reference voltage source. All further signal conversions, such as multiplication, filtering and addition, are performed over the digital signal. This approach provides very high stability and accuracy at ambient limits and over a long period of time.

Most enterprises in simple single-tariff meters use electromechanical meters, based on the principle of action, with non-volatile memory. And this corresponds to world practice. At the same time, at a relatively low cost, they are sensitive to strong magnetic fields, however, many times exceeding international test standards. The issue of quality of Russian reference devices is also not removed from the agenda. In multi-tariff counters with the display of additional information, LCD indicators are used everywhere. However, it must be borne in mind that they have a limited service life (10-12 years) and often do not provide the required temperature range, and if the LCD indicator fails, there is a technical and, possibly, legal problem of restoring meter readings.

Typically, electronic meters have a standard pulse output used for verification and remote transmission of readings. With all the simplicity, the pulse output has a serious drawback: after restoring the faulty communication channel, it is necessary to reinstall the counter readings in the data collector. In order to eliminate this and for other reasons, ASKUE developers insist on equipping counters with digital interfaces. Today, for household meters, this leads to their noticeable increase in price.

The main feature of ASKUE for household consumers is that, firstly, it is necessary to organize communication with a large number of meters, secondly, the amount of information transmitted from each meter and the number of communication sessions per day are small and, thirdly, there is a high probability of vandalism and inaccessibility to meters after settlement of the house. It is also obvious that it is inexpedient to unify technical solutions when creating ASKUE for urban mass development, elite housing, cottage settlements or rural settlements. Existing ASKUE of domestic consumers mainly differ in the method of physical implementation of the communication channel with meters.

More advanced are twisted pair or power grid systems. At the same time, conventional counters with pulse output can be used in combination with an intermediate "floor" hub installed with counters in one panel, or so-called "smart" counters with a digital interface or an integrated communication modem over a power network. The choice of the AESCO architecture and the method of communication are determined by the characteristic of the object, price factors, as well as the achieved level of development of technical means. The best prospects for ASKUE household consumers, of course, have a way of transmitting information over the power network, since it does not require the laying of communication cables and is actually protected from vandalism, and the technology of the so-called PLCmodems is actively developing around the world. GSMcs should also not be missed. The introduction of tariffs differentiated by the time of day, days of the week, etc., makes it necessary to use non-volatile hours with a calendar. In this regard, it is important to emphasize the peculiarity of counters with an internal charging device. The fact is that the electronic clock is prone to failure under conditions of real radio interference, without external support does not provide the required accuracy of travel, and the presence of a lithium battery in each meter necessitates a procedure for its repeated replacement during the life of the meter. As a result, and taking into account the increased cost of such devices, the proposal to create ASKUE for domestic consumers on the basis of meters with an internal charging device is controversial. Any ASCUE has a two-way connection of counters with a data collector, and only one common clock at each local level is enough.

Automated systems for energy control and accounting "Mercury Energy Accounting" are focused on use in residential and small-engine sectors, cottage and summer cottage villages, designed for measurements, automated registration, storage, processing, storage and display of data on electricity consumption, transfer of primary and analytical information to control and calculation centers, as well as for the implementation of functions of energy consumption and marketing management. ASKUE "Mercury ENERGY ACCOUNTING" includes the following devices :

1. Electric energy meters: single-phase Mercury 200, Mercury 201 with an integrated power network data modem (PLCmodem). Counters provide (depending on the modification) the accumulation and storage of energy consumption as a cumulative result.

2. Concentrator "Mercury 225" (single-channel digital data receiver over the power network and power storage).

- the concentrator synchronizes transmission and receives data from power meters in one phase and transmits them through the selected communication channel to the central control room.

- correction of values of internal parameters of counters by command from DPC;

- monitoring the state of power networks and counters with recording of failed and "abnormal" situations ;

- transmission of load control commands to metering devices and actuators via the power network.

3. A central computing device equipped with the necessary interface modules, a typical telephone modem, a printer, designed to:

- communication with DRC devices - for reception and processing of counter readings;

- generation of commands for energy consumption and marketing management. The functions of the central computing device can be performed by a portable personal computer (such as NoteBook) or a specialized console, with the help of which information is taken from a counter of any subscriber.

In ASKUE "MERCURY ENERGY ACCOUNTING" the measuring channel is built as follows. Counters with digital output provide information transmission to the Mercury 225.1 hub using the ESM as the interface.

The ESM is designed to exchange information between devices over the 220V power distribution network. The frequency range corresponds to CENELEC EN 500651. The communication channel type is half duplex. Data transfer rate over power lines 600/1200 Baud. The type of carrier frequency modulation in the communication channel is FSK. Transmission range without relay on hidden power lines - up to 500 m., On air power lines - up to 2000 m. Information interaction between devices is carried out according to the "response" scheme. The exchange protocol provides reliable control of the received information. The program logic of information exchange ensures the guaranteed delivery of information. Work planning, accumulation of information and its analytical processing is carried out using special software installed on the DPC computer. The exchange of information between the DAC and the DRC is usually initiated by the DAC. The exchange protocol includes mutual identification of subscribers.

Based on the analyzed systems, modems and electric meters, a remote energy consumption accounting system (DRE) is proposed, the structural diagram of which is shown in Figure 1.1 and on the poster.

Automated remote energy metering system using power meters is designed for automated metering and remote control of electricity consumption in the residential sector.

Development of schematic electrical diagram

4.1 Description of power meter schematic diagram

The electrical schematic diagram of the power meter for DRE is given in Appendix B and is also shown on the poster.

The power meter includes: matching device, power source, power converter, microprocessor, network transceiver.

Energy measurement is carried out by a power meter using a digital method with sample frequency equal to 4000 Hz (period 250 μs) of the measured voltage or current value. The numerical values corresponding to the input voltage in the current channel and the voltages are further multiplied, thus giving a value proportional to the instantaneous active power consumption. Based on the results of measurements for the network period, active power is calculated. Further, the power values thus obtained are accumulated in intermediate accumulators.

In order to provide communication with the network transceiver and then combine power meters into a local network at the site, the power meter is equipped with a current loop type interface. Physically, this interface consists of a pair of optical receiver transmitters, which are usually connected in series. For stable operation of the interface, it is enough to ensure that a current of about 10 mA flows in the loop. Each power meter has its own individual network address, which is initialized by zero and can subsequently be overridden by any desired value.

The command and information exchange of the control computer with the power meter is carried out in batch mode according to the "command response" principle. As a physical medium of information transmission, an ESM interface with the following parameters is used:

The transmission rate is 992 baud.

Transmission mode - 8 bits with odd parity check, 1 stopbit, lower bits forward.

The method of presenting information is binary byte. Each command consists of several fields transmitted one after the other without time breaks.

The power meter, as part of the system, is always driven, that is, it cannot transmit information to the channel without requesting the master, which is the control computer.

The control computer sends address requests to the power meters in the form of a sequence of binary bytes, to which the addressed power meter sends a response in the form of a sequence of binary bytes. The number of request and response bytes is not constant and depends on the nature of the request and the status of the counter. The bytes in the request and response sequences must follow each other, without time breaks, i.e. the stop bit of the previous byte must be followed by the start bit of the next byte, if any. The termination criterion of any sequence (frame) is a guaranteed timeout, the duration of which depends on the selected rate and is equal to the transmission time 6.. 7 bytes at the selected rate:

about 20 ms for a rate of 2400 Baud;

The request or response of the power meter to the request cannot be sent before the timeout, after the end of the previous request. Each request and response starts with a network address byte, and ends with two CRC checksum bytes.

To convert the current into voltage, a shunt is used, which is connected in series with the load of the consumer, and has a linear characteristic from milliampere units to 100A.

Two current sensors are connected to the AD7751, one of which is connected to the phase load wire, the other to the neutral one. The main one is the measurement in the phase wire, but if the output voltage of the current sensor drops by 12.5% compared to the sensor voltage in the neutral wire, the latter will automatically turn on. In general, when the chip is operating, the current sensor will be turned on, the voltage of which will exceed the voltage of the other by the indicated 12.5%. This mismatch, regardless of which sensor is on, will be signaled by the "1" level on the FAULT output. IE ADE7751, monitoring the current in both wires of the same two-wire circuit, provides maximum protection against unauthorized electricity consumption.

Input amplifiers of the current measurement channel ("Date. I ") have four gain values ​ ​ KycI = 1, 2, 8 and 16, corresponding to the maximum input voltages ± 660, ± 330, ± 82 and ± 41 mV (peak values ​ ​ at the differential input). Maximum channel input voltage "Date. U "is ± 660 mV. The negative power measurement in the ADE7751 is accompanied by "RevP" positive pulses corresponding to CF pulses.

In ADE7751, the output signal F1/F2 is proportional to the active power, and the output signal CF, being more high frequency, is also proportional to it, but contains residual pulsations of 100 Hz available at the output of the LPF turned on after the multiplier .

The voltage divider is used to obtain a voltage low enough to operate the ADC.

The power supply module is implemented on C5, C6, VD1, VD2 elements. The DA2 chip stabilizes the voltage at 5V to power the power meter .

VD2VD4 diodes, C11C22 capacitors and DA2 chip implement a 5B source galvanically isolated from the network to power and tie the microprocessor.

The PIC16F76 (DD3) microcontroller is synchronized from the ZQ2 quartz resonator.

The watchdog timer is implemented on the DD1 chip, and R23R24 elements. In normal operation, the microprocessor generates WDT braking pulses to output 6 of DD1 chip. If the microprocessor does not generate pulses, the WDT at terminal 7 generates reset pulses of the microprocessor. If the voltage level from the output of the supply voltage divider (R23, R24) is lower than the reference level WDT (1, 25V), then the low level from the output 5 WDT prevents the microcontroller from operating.

4.2.5.1 Transceiver features:

- using frequency keying to transmit information;

- possibility of carrier frequency selection;

-programmed rate up to 992 bps;

Interference-proof information encoding: single correction and double error detection;

-standard 22-pin DIP housing.

The location of conclusions of a chip of KP1446XK1 is given in figure 4.8.

4.2.5.2 Transmission of information

Transmission of information is carried out using frequency keying of the signal - "1" and "0" are transmitted at different frequencies slightly different from the central one upwards and downwards. The frequency-manipulated signal is transmitted through the decoupling transformer to the ~ 110 the 380V line. The buffer stage is designed to match the high output resistance of the microcircuit with the low input resistance of the line when transmitting the signal to the line and to filter the alternating voltage of 50Hz when receiving. It is recommended that you use an external filter to improve reception .

4.2.5.3 Reception of information

The receiver continuously analyzes the input data. If a synchronization word code comes in, followed by an address code that matches its own address (or a common address = 10111001ml), then the following 2 bytes of information are considered intended for this transceiver. They are written to the receive buffer, and at the output of the RX, the transceiver sets a high level, which is a flag that new information is received. As a result of interference in the network, information may be distorted. In each of the received bytes (address and data), the receiver corrects errors in one bit and detects double errors (in this case, the transceiver sets high at the output of ERR2). The obtained information will be stored in the reception buffer and can be read once or repeatedly at any convenient time regardless of the operation of the receiver and transmitter units. Figure 4.10 shows a diagram of information reception, where B [0:7] is the first byte of received information, B [8:15] is the second byte of received information.

The process of reading information from the receive buffer can be started immediately after the RX flag appears. To do this, set the high level at the W/R input and output 16 CLK pulses. The W/R front is required to perform the read procedure correctly, so if the W/R input was already high before, you must reset it to "0" and then set it to "1." The first CLK pulse resets the RX and ERR2 flags. The transceiver changes the DATA input information by the low CLK level. Both bytes of the received data are output in lower bits forward.

In order to perform the procedure of writing information to the transmission buffer, it is necessary to set the W/R input low and output 24 CLK pulses. The W/R slice is required to perform the read procedure correctly, so if the W/R input was already low before, it must be set to "1" and then set to "0." The DATA input information should be changed by the low CLK level. The address of the transceiver to which the information is addressed is transmitted (or the common address = 10111001ml in this case, the information will be received by all transceivers in this network) and 2 bytes of information. All bytes are transmitted with the least significant bits forward.

Once the information is written to the transmission buffer, it can be output once or repeatedly to the network. Transmission is started by START pulse front. The transmission time depends on the programmed rate. During the transmission process, the BUSY output is set to "1" and the receiver is blocked.

In the simplest case, it is possible to transmit the signal from one transceiver to another without first writing the transfer buffer and programming the settings. To do this, you need to reset all transceivers with the RESET signal, after which all addresses, data, speeds and frequencies are set to their default value of 01h. Then send START signal. The information 01h, 01h sent in this way to the address 01h will be received by all transceivers in this network, which will be marked by the appearance of the RX flag. RX reset is performed by RESET signal. or the 1st CLK pulse while reading the receive buffer .

4.2.5.4 Transceiver Programming

After powering on, all transceiver units must be reset to low RESET. RESET signal duration must be at least 1 ms. The RESET signal resets the RX, ERR2 flags, sets the transceiver native address to 01h, the transmission frequency to 100 KHz, the transmission rate to 248 bits/s, and sets the transmission address to 01h, the 1st data byte to 01h, and the 2nd data byte to 01h in the transmission buffer.

To perform the programming procedure, it is necessary to set the PROG and W/R inputs low and output 12 CLK pulses. The DATA input information should be changed by the high CLK level. The time limits are the same as for the recording procedure. At the DATA input, the address, frequency, and bit rate codes are sequentially set. In order for transceivers in the network to "hear each other," they must be programmed with the same frequency and transmission rate values.

4.2.6 Microcontroller Selection

Currently, devices operating in real time often contain a microcontroller as the main element of the circuit. The PIC16Ftraditix microcontrollers have power saving modes and the ability to protect program code.

5.2.6.1 Microcontroller Characteristic

High-Speed RISK Architecture

35 instructions

All commands are executed in one cycle. In addition to two-cycle hop instructions

Clock speed:

DC - 20 MHz, clock

DC - 200ns, one machine cycle

Up to 8k × 14 FLASH words program memory

Up to 368 × 8 bytes of data memory (RAM)

Up to 256 × 8 bytes of EEPROM data memory

Power On Reset (POR)

Reset Timer (PWRT) and Generator Start Wait Timer (OST) after Power On

Watchdog timer with native RC generator

Select Clock Parameters

Programming in the Finished Device

Low-voltage serial programming mode

Wide range of supply voltages from 2.0V to 5.5V

Multi-channel 10-bit ADC.

5.2.6.2 Electrical characteristics

The limit worker tempernaturaot-55 wasps up to +125 wasps

VDD voltage relative to VSS ----------------------------- 0.3V to + 7.5V.

MCLR voltage relative to VSS --------------------------------------0 to + 14V

Voltage RA4 relative to VSS ------------------------------------------------0 to + 8.5V.

Voltage at other leads relative to VSS ---------from -0.3V to

VDD + 0.3V

Dissipated power ------------------------------------------------------------------------------------- 1W

Maximum output current VSS --------------------------------------------------------------------- 300mA

Maximum output current VDD ----------------------------------------------------------------- 250mA

Input shut-off current IIK (V1 < 0 or V1 > VDD) --------------------- ± 20mA

Output closing current IOK (VO < 0 or VO > VDD) ----------------- ± 20mA

Maximum I/O channel drain output current 25mA

Maximum input/output source current 25mA

Maximum port drain output current

PORTA, PORTB and PORTE 200mA I/O

PORTA I/O port source maximum output current,

PORTB and PORTE 200mA

Maximum output drain current of PORTC I/O ports and

PORTD 200mA

Maximum input drain current of PORTC I/O ports and

PORTD 200mA

5.2.7 Power Supply Selection

For normal operation of this device, a low-voltage stabilized voltage of + 5 V is required, to power the digital-to-analog converter, microcontroller .

The power supply unit is made according to the classic circuit - rectification circuit, RC filter and + 5 V voltage stabilizer .

Organizational and Economic Part

The following issues are discussed here:

substantiation of the necessity and advisability of this development;

assessment of cost-effectiveness of decisions taken during diploma design;

Acquisition of theoretical and practical business planning skills.

This diploma project is dedicated to the development of a power meter, which is part of an automated system for technical accounting of electricity.

6. 1 Summary

In the diploma project, a power meter is being developed for the system of technical accounting of electricity. The customer and investor of this device is PromEnergo Scientific and Industrial Association CJSC. The performer is the Department of Information Radio Systems of the Nizhny Novgorod State Technical University. The department has a technical base and qualified personnel.

The proposed project does not involve repetitive production. A batch of ten units will be produced. The customer's investments will be spent on the purchase of necessary materials, components, labor and testing of the manufactured product.

6.2 Characteristics

This project is proposed by the Volga branch of the Research Institute of Electronic Emergency Forecasting Systems at the Nizhny Novgorod State Technical University, which carries out orders for research and development work.

The branch is a state-owned enterprise.

Address of the branch of N.Novgorod st. Minin d.24.

The development is carried out with the participation of the following structure:

- Radar systems (68%);

- Communication complexes (19%);

- Control systems (13%);

6.3 Project Description

The purpose of this diploma project is to develop a power meter for the power metering system. Most measuring devices continuously output measurement results to indicators. A distinctive feature of this power meter is the output of data only in cases of a request from the control panel, which allows you to connect a large number of power meters to one low-speed transmission line and use one control panel.

This project is focused on implementation within N. Novgorod, but can be adapted for enterprises of other cities.

The implementation of this project does not lead to environmental consequences because, first, the devices being developed are installed in power cabinets and at transformer substations, and second, all devices operate from electricity and, accordingly, do not pollute the environment.

This project makes extensive use of technological advances. The dispatcher workstation consists of two PCMs (one of which is standby) and a printer. Controllers use specialized microprocessors.

6.4 Services offered

It is proposed to develop a system of technical accounting of electric power and their automated control during operation and to create a demonstration area for pilot operation on the basis of developed tools.

The competing system is AIIS KUE Mercury Energy Accounting, the developer and manufacturer of which is INCOTEX Moscow.

The system as a whole allows:

Keep electric power records in automated mode;

remote reading of information in digital form (EPM interface) from power meters, storage and transfer of stored information via power lines of power grids upon request from the central control room (DPC);

- log system operation and operations of dispatchers.

A competing system meets the same needs, but costs a lot more.

The developed system has a number of differences that reduce the price: in particular, there is no indication and control unit, and all data are displayed on the screen of the manager computer.

6.5 Marketing Plan

The concept of marketing management, called "production improvement," was applied in the development of the UEE system, that is, a focus on increasing labor productivity and reducing the cost of products.

There is no need to take into account other factors due to the fact that the customer and his needs are clearly defined. At the same time, successful competition in price can be the key to long-term cooperation.

The promotion of technologies in the market is carried out by receiving development orders.

The price is determined after studying the demand of consumers and setting prices acceptable in the target market .

The price/performance ratio should be higher than the competition. The developed system belongs to the middle class, that is, it is designed for consumers who want to receive goods with average parameters for a moderate price. The cost of development is many times less than the cost of implementation.

Technology advertising is carried out in specialized publications and this allows you to focus on the target market.

Sales promotion is carried out by paying great attention to the organization of maintenance of installed systems.

The warranty life of the ESP systems is 2 years from the moment of commissioning.

6.6 Market Assessment

The main markets are large and medium-sized cities of Russia.

Consumers of such systems can be divided into three categories:

those for whom the high characteristics of the developed device are in the first place. For such consumers, there is AIIS KUE MERCURY ENERGY ACCOUNTING.

those for whom the price and characteristics of the device are equally important, that is, the price/performance ratio is the main one.

those who order the development of low-cost devices with low performance.

Potential customers for the development of TUE systems are enterprises engaged in the production of consumer goods (TNPs). Our company occupies a leading position in the development of middle-class ACS. The market share for such products is approximately 25% of the total market.

6.7 Competitive Analysis

There is monopolistic competition in this market.

Similar systems were developed in Omsk by LLC NPO Mir and INCOTEX Moscow.

Competing systems have higher manufacturing and operating costs, and they are oriented towards residential applications and require adaptation for small and large scale production.

In the future, competition from scientific centers of other cities is possible, since any automated control system can be adapted to any operating conditions.

6.8 Production Plan

Equipment for the demonstration site will be manufactured at the NSTU acoustic measurement laboratory, and equipment for the system itself will be manufactured at the M.V. Frunze plant. Three workshops will participate in the production: mechanical, galvanic, assembly.

The raw materials and materials used to make the block are purchased. Here is the calculation of the cost of materials and purchased products.

The cost of raw materials and materials for the production of the prototype is determined by price lists.

6.9 Organizational Plan

The development of ASU is carried out by order of Nizhnovenergo by the Volga branch of the Research Institute of Radioelectronic Emergency Forecasting Systems at the Nizhny Novgorod State Technical University.

6.9.1 Determination of general labour intensity of development and stages of ROC

The Operational Schedule (OCP) is the main calculation document for planning work on the development of the measurement module. It provides the basis for the preparation of quarterly and annual plans. The OCP specifies the stages of development on the topic with separation into stages, the number and composition of the development team, the timing of implementation and the labor intensity of the corresponding stages and stages. The starting point for the development of the OCP and the estimated costing of the topic is the legislative time frame for the development of the topic and its labor intensity.

We will use the method of expert assessments to determine labor intensity. As a basic option for determining labor intensity, the labor intensity of one of the previously developed topics was used: TB = 280 people/day. In order to determine the labour intensity of the new version, it is necessary to find a reduction factor, for which an expert commission was created, which included:

lead engineer

Category I Engineer

Grade II Engineer

Category I programmer

programmer of category II.

6.9.2 Determining the number of the development team

Based on the general labour intensity of development and the directive period of ROC implementation, we choose the following composition of developers:

lead engineer

Category I Development Engineer

Category II Design Engineer

Category I programmer

category II programmer

In addition, production workers take part in the creation of the prototype.

6.10 Legal Plan and Capital

The Volga branch is a state-owned enterprise that performs development at the expense of the customer.

The funds received are allocated for the purchase of raw materials and parts for models and prototypes of developed products, as well as for the salary of specialists involved in the development.

6.11 Risk Assessment

The risk on the part of the customer is that he will pay money for the development and will not receive the expected result.

The risk from the developer is that he will conduct the development and will not receive the promised money.

To reduce risks, all work is divided into several stages, each of which is financed separately.

Safety and Environmental Friendliness

The purpose of this section is to develop measures to ensure labor safety in the development of a system for remote accounting of electricity consumption, as well as to prevent the possibility of environmental pollution and the prevention of emergency and emergency situations. The development of the system is carried out at the Department of Information Radio Systems of the Nizhny Novgorod State Technical University. The workplace is a chair and a flat table with shelves on which the following devices are installed: a microwave oscillator, an oscilloscope, power supplies, a tester, and a personal computer with a monitor.

7.1 Analysis of hazardous and harmful production factors during development

Hazardous and harmful production factors acting on the development engineer during development and adjustment may be:

1) physical:

OPF:

increased value of voltage in the electric circuit, short circuits that can occur through the human body;

increased static electricity.

VPF:

increased or decreased air temperature of the working zone;

increased noise levels in the workplace;

increased or reduced air mobility;

increased or reduced air humidity;

increased level of electromagnetic radiation;

absence or lack of natural light;

insufficient illumination of the working area;

increased pulsation of light flux.

2) psychophysiological:

VPF:

physical overloads:

- static;

- dynamic;

neuropsychiatric overload:

- mental overvoltage;

- overvoltage of analyzers;

- monotonicity of labor;

- emotional overloads.

Conclusion: the most dangerous production factor in the development of a remote electricity metering system is psychophysiological VPF.

7.2 Analysis of hazardous and harmful production factors during operation

According to GOST 12.0.00374 * SSBT "Hazardous and Harmful Production Factors" at the dispatcher's automated workplace (AWS), the following factors related to physical VPF can be identified:

1. increased or decreased air temperature of the working zone;

2. increased noise levels in the workplace;

3. increased or reduced air mobility;

4. increased or reduced air humidity;

5. increased level of electromagnetic radiation;

6. absence or lack of natural light;

7. insufficient illumination of the working area;

8. increased pulsation of light flux.

Factors related to physical OPF: an increased value of voltage in the electrical circuit, the closure of which can occur through the human body.

Since the work of the dispatcher is associated with the use of personal computers, this leads to the emergence of harmful psychophysiological factors associated with mental overvoltage.

7.3 Production sanitation

7.3.1 Air Protection

Microclimate is defined by the following parameters:

- room air temperature t, ° C;

- relative humidity of air B,%;

- air speed U, m/s.

Meteorological conditions of the working area are given in Table 7.1 in accordance with SanPin 2.2.4.54896 "Hygienic requirements to the microclimate of production premises ."

7.3.2 Maintaining microclimate

According to SNiP 41012003 "Heating, ventilation and air conditioning" we select:

- radiator water heating is used to maintain the microclimate in the room in which this work is carried out;

- natural ventilation.

7.3.3 Production Lighting

The nature of the work performed in the room is the work with the computer and peripheral equipment of the computer, as well as recording. This is a high-precision operation with the smallest object size from 0.3 to 0.5 mm and according to SNiP 230595 "Natural and Artificial Lighting," this work has a discharge IIb. Table 7.2 shows lighting standards for this operation grade.

In daylight, combined lighting is used, in the dark - general artificial.

7.3.4 Noise Protection

The sources of noise in the central control room are computer cooling fans, peripheral equipment, gas discharge lamps, CRT devices.

The noise is constant broadband. Permissible sound pressure levels normalized in octave bands, in dB, are given in Table 7.3 according to GOST 12.1.00383 "Noise. General safety requirements "and MN 2.2.4/2.1.8.56296" Noise at workplaces, in premises of residential, public buildings and on the territory of residential buildings. "

Since the noise level in the working room does not exceed the specified values, special noise protection measures may not be provided.

7.4 Safety precautions

7.4.1 Safety of production equipment

In this case, the equipment requiring security measures is a computer and a modem.

In addition to electrical safety measures, a number of specific features of working with computers should be taken into account.

It is known that hours of observation of the CRT screen causes severe visual fatigue. Therefore, only special monitors with reduced tube radiation, rather than conventional home TVs, should be used as displays.

The optimal color is black and green. When working in color mode (with graphic information, when using CAD), it is advisable to use no more than 3-4 colors at a time.

7.4.2 Electrical safety

The department room according to the "Rules of Electrical Installations Devices" (PUE) belongs to the class of rooms with an increased danger of electric shock, since it is possible to simultaneously touch a person who is connected to the ground, metal structures, etc. - on the one hand, and the metal body of the electrical appliance - on the other. The department uses a three-phase four-wire network with a voltage of 220 V, alternating current with a frequency of 50 Hz with a blind-grounded neutral. There are electrical equipment units having a voltage of 220 V on one side and connected to the "ground" (grounded) metal structures on the other. The lighting network is also powered by a voltage of 220 V. The type of protection in the network is noise.

According to the requirements of SSBT GOST 12.1.01979 "Electrical safety. General Requirements "The following methods and means shall be used to provide protection against accidental contact with live parts:

- isolation of the workplace.

The following methods are used to provide protection against electric shock when touching non-conductive metal parts that may be energized by insulation damage:

- protective grounding;

- zeroing;

- protective shutdown;

- protection of the mains from mechanical damages;

- use of hidden wiring and location of non-detachable connecting devices of the network in inaccessible or inaccessible places;

-Indition of inscriptions on sockets or next to them about the value of supply voltage .

Protective grounding or grounding shall comply with the requirement of GOST 12.1.03081 "Protective grounding. Zeroing. "

Organizational arrangements:

- training;

- admission to work;

- appointment of persons responsible for the organization;

- organization of work supervision.

An AC network of 220 V, 50 Hz frequency is used to supply measuring instruments and devices at the workplace.

In a network with a de-grounded neutral during a single-phase closure to the housing, it is necessary to provide automatic disconnection of damaged electrical equipment. In case of short-term emergency mode, maintenance safety and safety of electrical equipment are created. However, short-term can only be ensured by creating a certain multiplicity of the short-circuit current to the housing with respect to the nominal current of the protective device. This can only be achieved by laying a special wire of sufficient conductivity - a zero wire to which electrical equipment enclosures are connected.

7.5 Organization of the workplace according to ergonomic requirements

The organization of the workplace depends on the nature, severity, monotony of work, as well as on the presence of harmful and dangerous factors.

7.5.1 Ergonomic requirements for the workplace

The workplace shall comply with the requirements specified in GOST 12.2.03278 "Workplace during sitting work," provide the possibility of convenient performance of works SanPiN 2.2.2/2.4.134003 "Hygienic requirements for personal electronic computing machines and organization of work."

When the dispatcher operates, it is important to determine the radius of the work area, depending on the position of the working area, its mobility, force and features of the activity. Table 7.4 shows the workplace parameters.

The following basic conditions must be met:

- Create free and adequate space to allow for all necessary movements and movements in the course of employment;

- To ensure sufficient physical, visual and auditory communication between the working person and the equipment, as well as between people in the course of the general work task;

- optimal placement of workplaces in the production room, provision of passageways for working people;

- determine permissible values of operating medium factors (noise, vibration, illumination, etc.);

- To create the necessary means of protecting workers from hazardous factors at work.

Conclusion

The diploma project was completed in full in accordance with the task .

Structural and functional diagrams of the power meter are compiled. Electrical calculation of bands - transmission filter, attenuator, which are part of receiver, and amplifier of low frequency unit is carried out.

Calculation has been made:

- transmitter capacity;

- limit sensitivity of receiver;

- potential and root-mean-square errors of radar meter of reflecting characteristics of ground surface.

Designed mirror antenna. Antenna geometry, directional pattern, directional factor, gain factor are calculated. Based on the results of the calculation, a prototype antenna was made and the directivity pattern and gain were experimentally measured. The experiment showed that the results of the calculation are consistent with the experiment.

This work covers APCS BP systems. Their main characteristics are shown. An analysis of the modern market of electric network modems showed that it is possible to build systems for technical accounting of electricity using ESM for transmitting data on electric networks.

As a result of the development of the DRE system, I have gained experience in designing such systems. The possibility of sharing analog and digital devices to implement specific operations has been studied. Knowledge of the foreign element base was obtained (there was no such knowledge before the development of this project), as well as some experience in the design of combined analogue-to-digital devices.

During the graduation project, software packages were used for calculations. MathCAD The AutoCAD package was used to execute the drawings.

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