Gas Metering

Introduction for Gas Metering Wizard

inSCADA provides a wizard for natural gas measuring stations that automatically creates a project for monitoring, control and reporting needs. Using this wizard, you can make all the settings and configurations required for gas measuring stations in a few minutes. The wizard prepares all the configurations of your project such as:

• Connections,

• Devices and Frames,

• Variables,

• Visualizations,

• Trends,

• Alarms,

• Reports,

• Station Calculations,

• KEY-PAD Management,

• C6+ Split Modes,

• Pay/Check Metering,

• Data Sharing (With dnp3 Outstation for central scada applications or with Modbus TCP Server / Client for other local scada systems).

Gas Metering System Model

inSCADA models gas measuring systems as shown in figure 1.

Figure 1 : Gas Metering System Model

As seen in the model, inSCADA Gas Metering System is a general model that models gas entries and exits, even pay and check metering systems that contain measurement groups. Here, the main measurement groups GRP01 and GRP02 to which the gas enters, the INT measurement group modeling the internal consumption, and the GRP03 and GRP04 measurement groups that model additional measurement stations at the station exit are shown.

There is no limitation in the measurement line numbers of measurement groups.

inSCADA uses a discipline in naming parameters and variables when creating projects suitable for gas measurement systems. It can automatically generate the project correctly through the template devices named in this discipline and the variables defined within these devices.

Structure of variable names;

STN{x}_GRP{y}_PAY_STREAM{z}_{NAME}

x in the STN{x} is a station number. Model in the Figure 1 models the case that a project can contain 2 stations. As in the below figure, STN{x} value is 01 and 02 for Station 1 and Station 2, respectively. In this case, the names STN01 and STN02 are used in the naming.

Figure 2 : Station Model

The y value in GRP{y} indicates which measurement group exists in each station. As seen in Figure 2, possible group numbers are shown as 01, 02, 03, 04.

The CHK statement may also replace the PAY statement. PAY means that the line is the share measurement line, and CHK is the check measurement line.

z in STREAM{z} represents the measurement line number. It increments according to the number of measurement lines e.g. STREAM01, STREAM02, STREAM03. STREAM00 has a special definition. It represents all lines of the related group. For example,

STN01_GRP01_PAY_STREAM01_LINE_PRESSURE : 55
STN01_GRP01_PAY_STREAM02_LINE_PRESSURE : 60
STN01_GRP01_PAY_STREAM01_CORRECTED_FLOW_RATE : 100
STN01_GRP01_PAY_STREAM02_CORRECTED_FLOW_RATE : 50

STN01_GRP01_PAY_STREAM00_LINE_PRESSURE = ?

The line pressure of the group 01 measuring group with sample 
values as above is automatically calculated as follows.

STN01_GRP01_PAY_STREAM00_LINE_PRESSURE= (55*100+60*50)/(100+50)=56,66 

{NAME} represents the actual definition of the variable, and the prefix of name refers to where it belongs, as described above. In all variable names, the abbreviations used in addition to the details above have a meaning and are important for the correct operation of the system. They are

Abbreviation	Description	Example
PH	Previous Hour	STN01_GRP01_PAY_STREAM01_PH_LINE_PRESSURE
PD	Previous Day	STN01_GRP01_PAY_STREAM01_PD_LINE_PRESSURE
PW	Previous Week	STN01_GRP01_PAY_STREAM01_PW_LINE_PRESSURE
PM	Previous Month	STN01_GRP01_PAY_STREAM01_PM_LINE_PRESSURE
PY	Previous Year	STN01_GRP01_PAY_STREAM01_PY_LINE_PRESSURE
SSH	Snap Shoot Hour	STN01_GRP01_PAY_STREAM01_SSH_CORRECTED_TOTAL
TOTAL	Total	STN01_GRP01_PAY_STREAM01_UNCORRECTED_TOTAL
CORRECTED_FLOW_RATE	Uses for Flow Weighted Avarage	STN01_GRP01_PAY_STREAM01_CORRECTED_FLOW_RATE

The expressions given in the table above are used in variable names. The order and notation is important. InSCADA decides which variables should be processed by looking at these statements.

Step By Step Practice

In this section, we will go over a natural gas station with examples and see how you can quickly create the most suitable project with inSCADA.

Example 1 : Let our measuring station be 2 parallel Turbinmeter measuring lines, a serial ultrasonic measuring line to this turbinmeter measuring line, 1 fuel line for internal need, 1 gas chromotograph. SPIRIT XP3 model flow computer will be used in the measurement lines and RFLO brand correcter will be used in the fuel line.

Step 1 : Adding Device to Device List