SPP – distribúcia distributes natural gas to customers in Slovakia through gas pipelines operated at different pressure levels. The gas pipeline network has a total length of more than 32 500 km, of which the length of high-pressure gas pipelines (with pressure above 0.4 MPa) is nearly 6 300 km and the length of medium and low-pressure gas pipelines with pressure up to 0.4 MPA (inclusive) is more than 26 200 km. From the total length of medium and low-pressure gas pipelines, one half is made of polyethylene.
The high-pressure gas pipeline system covers a substantial part of the territory of the Slovak Republic and supplies natural gas to final consumers.
A good condition of the distribution network and its systematic checks and diagnostics are the condition of safe and reliable gas distribution.
The company SPP – distribúcia carries out all required operation and maintenance activities on its gas facilities in accordance with legislative conditions and its internal regulations. The preventive maintenance system serves not only for safe and reliable gas distribution, but also provides information for planning of reconstruction works related to modernisation of the distribution network.
Systém preventívnej údržby slúži nielen na zaistenie bezpečnej a spoľahlivej distribúcie plynu ale poskytuje tiež informácie pre plánovanie rekonštrukčných činností spojených s obnovou distribučnej siete.
Preventive works include e.g. professional inspections and tests, measurements of gas pipeline tightness, as well as so-called internal and external inspections of gas pipelines. The aim of these activities is the detection and removal of potential damage to the gas pipelines.
Technological objects are an integral part of the distribution network of SPP – distribúcia. The basic technological objects are regulation stations and offtake stations (RS and OS) that serve for reduction of gas pressure.
The company presently operates approximately 1 750 RS connected to high and medium-pressure distribution gas pipelines. RS are built as single or two-row and single or two-stage regulation stations.
Offtake stations serve for reduction of gas pressure for high-pressure distribution network. The layout of OS in the distribution network of SR meets the commercial requirements as well as the needs of creation of a multi-circuit high-pressure gas pipeline network. SPP – distribúcia currently operates 35 OS.
RS and OS are situated in buildings equipped by electric and electronic devices. Pressure gas reduction is implemented in the technological part. This contains shut-off valves, filtration equipment, gas heaters, safety equipment (for automatic shutdown in case of exceeding of limit gas pressure values), regulation devices, measuring instruments and safety components.
These devices and equipment are interconnected by pipes with required dimensions with installed pressure and temperature transfer sensors and visual meters serving for their control. The technological part comprises odorization devices or stations. The main objective of natural gas odorization is to ensure an operation status where odorized gas in each point of distribution network or in offtake gas equipment will permanently report a warning intensity of odour not later than upon achievement of dangerous gas concentration in case of its leak from the distribution network or offtake gas equipment.
For the enhancement of the effectiveness of RS and OS operation, these stations are equipped by control systems SCADA (Supervisor and Control Data Acquisition) that ensure reliable monitoring and data transmission to central dispatching. In case of failure or accident the monitoring system enables immediate intervention with optimization of gas transport and distribution management until its removal.
SPP – distribúcia continuously works on improvement of technological components of RS and OS, which significantly increases the operating safety and reliability of natural gas supply to technological units in the gas industry.
The company implements anticorrosion protection of distribution gas pipelines by cathodic protection stations, current drainages and galvanic anodes. Virtually the whole high-pressure gas pipeline system is provided with active anticorrosion protection. The anticorrosion protection of gas pipelines is implemented through about 550 cathodic protection stations and 50 current drainages. Current drainages are located in areas where steel gas pipelines run alongside or in close proximity of unidirectional railway electric traction.
Since the year 1995 the company SPP – distribúcia has also applied active anticorrosion protection to steel gas pipelines of the distribution network under pressure equal or lower than 0.4 MPa. At present approximately 3 500 km of these gas pipelines are provided with this protection. Active anticorrosion protection of these gas pipelines is particularly implemented by their interconnection with high-pressure gas pipelines in sites with sufficient power reserve of cathodic protection stations on high-pressure gas pipelines and by construction of new cathodic protection stations for gas pipelines with pressure not exceeding 0.4 MPa. In both cases the gas pipelines must be properly insulated from ground system.