Automated system for integrated accounting of fuel and energy resources of the Trans-Baikal Railway

Contents

1 GENERAL DATA

2 HEAT CARRIER DESIGN PARAMETERS AND HEAT LOAD

3 JUSTIFICATION OF EQUIPMENT SELECTION

4 CALCULATION OF HYDRAULIC LOSSES IN PIPELINES

5 INSTALLATION OF ELECTRICAL CIRCUITS

6 ANTI-VANDAL ACTIVITIES

1 general data

1.1 Purpose of metering unit. The cold water metering unit is designed for automated measurement and accounting of the volume flow rate of cold water in the boiler house PM5 RTSTV-2 st. Chernyshevsk .

1.2 Heat supply system characteristic - closed, double-tube.

1.3 The project is carried out in accordance with the "Rules for accounting of thermal energy and coolant," approved by the First Deputy Minister of Fuel and Energy of the Russian Federation V.N. Kostyunin of 12.09.95.

1.4 Technical solutions adopted in the working drawings comply with the requirements of environmental, sanitary, fire and other applicable norms and regulations, ensure safe operation of the facility for life and health of people, subject to the measures provided for in the working drawings.

1.5 The facility is supplied via steel pipeline with diameter Dn of 80 mm. In accordance with the specifications, the place of installation of the metering device is characterized by the following parameters:

diameter of supply pipeline - Dn 80 mm;

nominal water pressure in the supply pipeline - 8 kgf/m2;

1.6 The metering unit includes:

Thermal calculator Logic SPT961.2 (manufactured by AOZT NPF LOGIKA, St. Petersburg);

electromagnetic flow converter PREM (manufactured by CJSC "TEPLOKOM," St. Petersburg) - 1 pc.;

cold water temperature converter TPT13 (manufactured by LLC Teremko);

pipeline valves.

1.7 Metering unit provides measurement of the following parameters of the measured medium:

temperature;

volume flow rate of coolant.

3.2 Selection of thermal transducers

Cold water temperature sensors TPT13 are installed to determine the required amount of heat released to the heat network in accordance with the approved temperature schedule.

3.3 Selection of pressure sensors

Metran55DI515 overpressure converter (manufactured by Metran SG CJSC) is selected for pressure measurement in the pipeline. Operating temperature range 40... 700С. The range of measured pressures is 0- 1.6 MPa .

To protect the pressure transmitter from the high temperature of the measured medium (up to 2000C), an annular (siphon) pipe is used.

3.4 Thermal calculator selection.

The organization of energy carrier consumption accounting is carried out on the basis of SPT961.2 thermal calculator and ADS97 input configuration expander.

Short characteristic of thermal calculator SPT961.2:

heat calculator is intended for application in composite heat meters.

converts the output signals of the coolant flow, temperature and pressure sensors into physical values;

calculates and keeps commercial records of heat and heat carrier mass;

is a measuring instrument and is registered in the State Register of Measuring Instruments;

the device meets the requirements of the Rules for accounting of thermal energy and coolant and recommendation P75 of the International Organization of Legislative Metrology.

The heat calculator can serve up to five pipelines, which can belong to one or two heat supply or heat consumption lines. In different pipelines there may be different coolant from the above and different types of flow, temperature and pressure sensors.

The device allows to monitor thermal and hydraulic modes of heat supply and heat consumption systems.

SPT961.2 is used in automated systems of energy and energy resources accounting and control.

Electrical power supply of the device is carried out from a single-phase AC network of 220 V, 50 Hz. Long-term voltage deviation within ± 30% and frequency within ± 1 Hz from nominal values is allowed.

Power consumed by the instrument does not exceed 7 VA.

Climatic conditions under which the device can be used:

ambient air temperature from minus 10 to plus 50 ° С;

relative humidity up to 98% at a temperature of 25 ° C and lower.

The device is resistant to external magnetic field with intensity of 400 A/m and frequency (50 ± 1) Hz.

The device is resistant to vibration with frequency up to 25 Hz and amplitude not more than 0.1 mm.

Electrical resistance of the device power circuit insulation relative to the housing and other circuits:

40 MOhm - at ambient air temperature (20 ± 5) ° С and relative humidity not more than 80%;

20 MOhm - at ambient air temperature 50 ° С and relative humidity not more than 65%.

Electrical insulation of the power circuit of the device relative to the housing and other circuits at ambient temperature (20 ± 5) ° С and relative humidity of not more than 80% withstands for 1 minute the effect of the test voltage of 1500 V with a frequency of (50 ± 1) Hz.

Average time between failures of SPT961.2 is not less than 40,000 hours.

ADS97 adapters are designed to measure the informative parameters of electrical signals (frequency and number of pulses, current strength, resistance to electric current) corresponding to the parameters of flows of liquids or gases transported through pipelines (flow rate or pressure drop, temperature, pressure, density, viscosity, etc.), convert the measured values ​ ​ of informative parameters into a digital code and then transmit digital data to SPT961.2.

Adapters are designed to work together with the above-mentioned computer as part of measuring complexes (systems) designed to take into account thermal energy and heat carriers, natural and other technically important gases, as well as stable and unstable gas condensates and a wide fraction of light hydrocarbons.

Functionality of the ADS97 adapter:

Instruments are designed to work with input signals of current, resistance, numerical pulse and frequency signals. The following can be connected to the adapter :

• four converters with a current output of 05, 0-20 or 420 mA;

• four converters with output pulse or frequency signal 0-5 kHz;

• four resistance temperature transducers with the characteristic 50P, Pt50, 100P, Pt100, 50M, 100M.

The adapters are provided with an RS485 interface. The digitized measured values of the information parameters are transmitted via the RS485 interface to the corresponding computer. Data exchange with the computer is carried out in master-slave mode, the computer is the master, the data exchange rate is from 2400 to 57600 baud.

In operating mode, adapters cyclically display measured values of informative parameters on the annunciator. Display of information on the annunciator can be disabled if necessary.

In the setting mode, the display displays the version of the adapter program, as well as its tuning parameters: address, exchange speed via RS485 interface, sign of information output to the display in operating mode and sign of filter activation for number-pulse signals. All settings can only be changed when protection is turned off.

When protection is off, measured values of informative parameters are not only not displayed on the annunciator, but are not transmitted via RS485 interface.

Metrological characteristics of ADS97 adapter:

Error in operating conditions does not exceed:

± 0.05% - (relative) by measurement of frequency signals;

± 0.05% - (reduced) as measured by signals 020 and 420 mA;

± 0.1% - (reduced) by measurement of signals 0-5 mA;

± 0.03 Ohm - (absolute) by measurement of resistance signals.

Performance of ADS97 adapter:

Overall dimensions - 178 x 194 x 64 mm.

Power supply - 220 V ± 30%, (50 ± 1) Hz.

Power consumption - 7 VA.

Resistance to operating conditions:

- temperature - from (10) to 50 ° С ;

- relative humidity - 95% at 35 ° С.

The degree of protection against dust and water is IP54 as per GOST 1425496 .

Calculation by the heat meter is made according to the formula:

Q = Mxv

where hv - the pipeline of the cold water used for feed.

5 installation of electrical circuits

Sensors and other external equipment are connected to the computer by multicore cables. After the cable ends are cut for installation:

- a cable tip is put on the cut ends and crimped with specialized ticks (crimper);

- the prepared cables are passed through the cable entries installed on the cover of the installation compartment, after which the swivel nuts are wrapped so as to ensure the mechanical strength of the cables fixation and compression of the gland seals;

- ends of strands are fixed in plugs equipped with screw clamps.

The maximum cross section of each core is 1.5 mm2. The diameter range of the cables used is limited by the design of the cable glands. The declared degree of protection against dust and moisture is provided only when using rounded cables. To protect against industrial interference, it is recommended to use shielded cables, metal shells or metal pipes, but such a decision should be made for a particular metering unit. It is not allowed to lay measuring chains in one metal sleeve (pipe) with power circuits.

Under operating conditions, interference can be caused by various factors, for example, the operation of thyristor and other frequency converters, switching of powerful loads using relays and contactors, short circuits and arc discharges in electrical installations, sharp changes in load in electrical distribution systems, actuation of protective devices in electrical networks, electromagnetic fields from radio and television transmitters, indirect lightning discharges, etc.

The working grounding of the cable screens shall be performed at only one point, usually on the heat absorber side. The braids shall be electrically insulated along the entire length of the cable and shall not be used for grounding of the sensor housings and other equipment. If in the immediate vicinity (within a radius of less than 20 meters) from the equipment of the metering unit there are no industrial units capable of generating the above and similar factors of interference, unscreened cables can be used.

Power supply (~ 220 V) is carried out from the existing power panel .

For mechanical protection, cables are installed in PVC hoses, which are laid in metal boxes.

6 anti-vandal events

To prevent unauthorized access to the equipment of metering units, rooms, cabinets in which the equipment is located should be locked. Measuring instruments shall be sealed.