ELECTRICAL AND INSTRUMENTATION INSTALLATION PERIOD IN INDUSTRIAL FACILITIES

ELECTRICAL AND INSTRUMENTATION INSTALLATION PERIOD IN INDUSTRIAL FACILITIES

An industrial facility means a facility engaged in activities such as an agriculture, a forestry, a fishing, a mining, a production, a transportation, a communications or providing services including an electricity, a gas and a sanitary services. There are some on going projects, a huge projects those are Star, Petkim, Tüpraş, Akkuyu and they are focused on oil, gas and energy. In addition to this, over 50,000 factories in 325 organized industrial zones as an industrial facility is available.

The most important period after civil and mechanical construction works in projects is an electrical-instrumental installation period of the project. This period is extremely important for commissioning and monitoring the functionality of the project. So what are electrical and instrumentation?

Electrical and instrumental installation period can be evaluated as a 2 different periods . It can be thought that the electrical period is the process of transmitting energy to all sub-units such as motors, from the moment of plant energization. An instrument is a kind of an industrial sensor. All input such as a flow, a gas, a temperature and a level that are desired to be examined as in information in the plant are reached with these devices. The electrical installation period includes earthing, piping, cable tray installation, cable pulling, installation of equipment such as motors, generators, transformers, cubicles, panels, lighting equipment installation, lighting cable pulling, heating cable pulling and finally the completion of all termination work. Instrument installation period includes the process of installation of instrument supports, instrument cable pulling, installation of instruments, installation of tubing, installation of closed-circuit camera system, installation of equipment such as loudspeakers, telephones, and installation of telecom infrastructure.

Electrical-instrumentation installation progress can be examined in two parts as infrastructure and superstructure. Grounding and conduit installation period can be thought as an infrastructure phase in the electrical installation period. So what is grounding? Grounding is the method of connecting the bodies of the electrical devices to the grounding system with a grounding line buried in the ground against any danger of electric leakage. Grounding equipment consists of yellow-green insulated or uninsulated copper cable, grounding pit, grounding rod, copper busbar and apparatus for connecting them with thermit welding or connector and lugs. Branched yellow-green insulated cables, which are left at the ground level are being used when the superstructure process will be started and to be connected to the grounding line formed in accordance with the engineering calculation, will provide grounding of the elements such as lightning protections, equipments, steels and supports needed. During the installation process, the projects are complied with engineering calculations and cables are pulled underground level in the way of calculated depth. Cables are pulled to earthing rods buried underground at regular intervals. According to the requested installation details, these cables are connected to each other with using connectors or thermit welding. From these cables, branch cables are pulled to the surface as a green-yellow insulated in superstructure period. On the surface, these cables will be connected to copper busbars with using cable lugs and the grounding process will be continued with using green-yellow insulated cables to an any desired point of the substations, structures or a pipe rack. Infrastructure conduit installation process allows the cables to be pulled from the infrastructure to the superstructure. Conduits connected to the underground cable way allow the cables to reach the superstructure through the conduit.

Conduit is usually preferred from galvanized steel material so as to prevent corrosion. A galvanized steel conduit pipe has couplings at front and end points of conduit itself. The muff coupling provides connection of the pipes to each other. The piping function is also used where the cable tray cannot be reached in the superstructure. In general use, although the pipes are not connected to each other, couplings are used at end point of the conduit so as to prevent  contact  of an incoming cable with the sharp edge of conduit pipe. It may cause tearing of the insulation. According to engineering calculations and the demand of a plant a corrugated and similar types are preferred instead of galvanized steel conduit in various plants.

In electical installation period, superstructure works has been continued in itself with equipment installation. What is an equipment? Equipment is the thing that cause the process of transferring energy to the smallest unit in all sub-stations and sub-units. Equipments are installed as motors, transformers, generators, cubicles or panels within superstructure works. A transformer is an electrical device that connects two or more electrical circuits by electromagnetic induction. The motor is a machine that converts an energy form into mechanical energy. A generator is a device that converts mechanical energy into the electrical energy. The source of mechanical energy can be a steam engine, water, an internal combustion engine or a wind turbine. Cubicle or panel as a circuit breaker, a disconnector, a load disconnector, an earth disconnector, a current measuring transformer, a voltage measuring transformer. In fact, energy management in industrial plants is like a very large electronic circuit. We can continue to search this process by giving an example to the refinery installation period in industrial enviroment. In major industrial projects such as refineries, the main substation and substations are available. Finally our project is a refinery with those units and substations and 154 kV is our base point of energy. Energy is firstly taken to the main substation with using of  cables. Cables are connected to the transformers which reduce the 154 kV to 34.5 kV. Connection of cables and transformers are being supplied with using bus duct as an equipment. The bus duct is a sheet metal with copper or aluminum bars for conducting large amounts of electrical current in the distribution of electrical energy. In this period, transformer body is installed by Crane as to be fixed to the foundation with steel bolts. In the second stage, oil tanks and other aparatus will be installed and so on. Equipments of a transformer are installed according to its technical data sheets. As a second step, the transformers have been connected to 34.5 kV circuit breakers with pulled 1x630 mm2 cables or similars. Thus, energy can be reduced. It can also be reduced to 6.3 kV and 0.4 kV with using lowering transformers installed at substations. Now cables can be terminated to panels of related motors and equipments at side from transformers. Systems are running now. The most important feature of these systems is that the facility is redundant for the continuity of operation. In some systems, the 34.5 kV can also be reduced to 0.4 kV. This is an engineering calculation of what the plant needs.

Energy can now be transferred from the main substation to substations. Energy transmitting from a substation to a site has been continued in infrastructure and superstructure. Underground cable ways and conduits are ready in infrastructure. Cables can be pulled from underground cable ways and installed  conduits to the way of superstructure. There are many kinds of cables. Armored cables are generally preferred in industrial facilities such as refineries. Armored cables increase the protection of the cable in such periods like excavation and so on. Grounding of the cable armor may help shut down of the system in the case of damage. In the selection period of cable termination or joint kits or additional apparatuses of these kits to be carefully selected in the way of detailed analizing of termination or joint point. Cables are being pulled in the underground cable way with sand backfilling or a similar method and so on. Generally, medium voltage cables and low voltage cables are pulled apart with using bricks or seperators due to the magnetic field that may occur with the energy to pass through the medium voltage cables between the cables. Medium voltage cables are also pulled in the form of trefoil-clover. The subject of trefoil is also related to the magnetic field emitted by medium voltage cables. Magnetic field cause vibration etc. and it may cause issues. Trefoil kind pulled cables have a same way magnetic field with respect to the phases of the transformer. This is detailed engineering traffic. The cables are not connected directly to the surface level with an equipment in the superstructure. It can be at any height and anywhere in the unit according to need of equipments. Cables are pulled from cable trays in aboveground. A cable tray is the thing that is used to help reaching of one or more cables in the superstructure to a place where cables need to be reached. They are usually being preffered as a ladder or a perforated type. Movable types are also available in mobile lines used in various industrial plants. The installation organization of cable trays is a process that must be carefully planned. For this purpose, scaffolding, manlift and crane organization can be planned simultaneously with cable pulling. For cable trays, first of all, supports of cable trays are welded to the structure by welding method. Supports are angles and u-type profiles. After supports are welded, it is important to paint the structure with anticorrosive primer paint and top paints. Rust can grow over the years, causing damage to the structure. Primer paint is a preparation coating that is placed on the materials before painting. The primer provides better adhesion of the paint to the surface, increases paint resistance and provides additional protection for the painted material. After supports are welded, cable trays are installed. The cable tray can be bolted to the supports at certain intervals according to the weight of the unit meter cable to be passed over cable tray calculated by the project engineering. In this case, it is also important to paint the primed parts with topcoat to prevent rusting of the pierced parts. Cable tray vertical and horrizontal points which are manufactured in accordance to needs at site has to be prevented from sharp edges and after the manufacturing, the cable tray is protected against corrosion by galvanizing spray. If the sharp corners are not taken into manufacturing period, the installation of the cables pulled in the second stage can be torn and damaged. All these steps should be followed carefully and carefully. In general, in such facilities, since the project continues for 2-3 years, some items installed in the first year of the project start to show rust if they are not paid attention in 2 or 3 years. During the intensive installation period, the maintenance period for the missed areas should be considered as a separate item or considered as extra man-hours in the calculations of the installation periods.

Cable tray installation and cable pulling periods consists of the same stages in electrical and instrument installation periods. Instrument cables are also pulled from the main substation-rib to the instruments installed at site as a result of engineering calculations in the field. In this periods, the underground cable ways preffered in infrastructure and cable trays at superstructure. Generally, conduits are preferred in subjects such as aboveground lighting. Conduits are also installed on supports with c-type fasteners. Since the lighting equipment is usually installed in independent areas seperately, 2 ”pipes through which a maximum of 2 cables pass can be preferred for that kind of installation. In the lighting installation period, it is an important subject to install lighting equipments from starting areas that mechanical and civil installation period are completed. Other equipment may damage the lighting equipment during installation in areas where the work is in progress.

The aboveground instrument installation period is usually like the electrical installation period. The only difference here, there are instruments instead of equipments such as motors, fans, and cables of instruments need to be reached to the end point as instruments. The instrument allows the detection of effects such as temperature, level, pressure, flow, flame and gas and monitoring on monitors in areas such as the operator building. Some instruments have indicators on the ground, depending on where the instrument is mounted, for on-site monitoring in the field. Cable pulling is also performed between the instrument and the display. In projects with pipelines such as refineries, instruments can be installed at different heights depending on the level of the pipe and the liquid or gas flowing through it, or can be mounted directly on the pipeline. In the case of instruments mounted above or below the level of this type of pipeline, the instrument and the pipeline are connected to each other by tubing. Tubing is a kind of stainless pipe. Tubing allows liquid or gas to be taken into the instrument. In this way, the instrument can perform the measurement task in accordance with the relevant parameter and convert it to some kind of electrical signal and transmit the data to the monitors via the panels in the instrument room in the substation. Instruments can be mounted on the platform or on the floor with galvanized supports. Support models for instruments are independent. Generally, mounting supports are determined in detail according to types of instruments purchased by the engineering prior to the project. The correct operation of the instruments, which have been assembled to the appropriate places with their supports, is checked during the commissioning process by loop test. Before the commissioning process, the instruments go through the calibration process in the calibration laboratories before the instruments are installed. Calibration is the process of measuring the correct operation of the instrument according to a certain measurement standard and determining its deviations under specified conditions. The instruments are periodically calibrated after commissioning, depending on where they are used. It is an important to maintain instruments installed in or around the pipeline while mechanical operations are in progress. Boxes manufactured in the carpenter's workshop can be placed on instruments for protection against external influences. In the aboveground, telecom system, alarm system, closed circuit camera system and loudspeaker system are also mounted by pulling cables. The tubing assembly can be mounted on air-operated components, except for instruments. The air cover opened and closed for signaling like some valves and so on. The equipment is mounted between the devices with the tubing air line.

Electrical-instrument connection period as a completing of connection must be evaluated separately. In large installations, 5000 to 10.000 connections are planned in just for a unit. The connection is known as a termination. Termination is the thing that the connection of cores to terminals for cables which are pulled to panels, boxes, etc. It is the process of connecting and terminating according to the engineering standards to the terminal blocks within panels. The terminal is called connection place of the cable cores. Continuing with the refinery sample, areas such as refineries are considered to be in accordance with the ATEX standard. ATEX is “ATmosphere EXpolosible” as a defination. Exproof product can be installed according to ATEX instructions. Exproof means flameproof or explosive resistance. The cable glands and accessories, which are preferred for termination, are resistant to explosive environments. Termination aparatuses are glands, adapters, sleeves, earthing rings, reducers, glands and gland jackets. When the termination period is started in industrial facilities, it is an important issue that the cable pulling period is completed. The connection is completed by cutting the waste footage of pulled cable calculated by the project engineering on the cables whose drafting process is completed. In the waste footage, it is determined to be between 3 and 5 meters according to the growth at the connection point of the cable. If this situation is exceeded, cable drums may not complete the project unit. Dressing is an important issue after cable pulling. Dressing is laying of cables in the tray with using clips and so on. The tray cover is closed for dressed cables after then. If the scaffolding can not be organized correctly at high-levels, tray cover closure period may be forgotten and it may cause extra man hour and work as a work front. The termination period is faced on the cores of cable in the panel or the box of medium voltage equipments. It is used to prevent the electrical terminals from being removed from the control panel to prevent them from being affected by moisture and dust and against short circuit stresses. Heat shrinkable, cold shrinkable and plug type cable kits are available. Generally, heat shrinkable kit is preferred.

In the installation periods, the existing works for the electric-instrument process should be planned separately and calculated well according to the field conditions. According to the total number of these items, man-hour planning should be done correctly and employees to be mobilized to the site should be at the right times in the right places. In such areas where open area works such as projects are carried out, the weather conditions should be examined thoroughly and the employees should be backed up accordingly in the ongoing works at winter conditions. If these items are not planned synchronized with each other and are not approached carefully, problems that you cannot foresee may turn into unpredictable man-hour as your project approaches the end. In this way, you may have to direct personnel to the items you previously paid.

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