Offshore: Microwave Radio use in Explosive Situations

• September 21, 2015
• AATS, ATEX, BATS, flammable gas, FPSO, IECEx Zone 1, Microwave Radio, microwave radios, odu 600, offshore

In oil and gas exploration, danger’s part of the business. In particular, offshore drilling is hazardous (e.g., water inundation, drill-hole blowouts). However, there are acceptable levels of risk, and the industry participants take those into account when they work in the field. But one item that should not be a hazard is the microwave radio installations rigs and other platforms use to communicate to shore.

As all know, microwave radios use a certain amount of electricity in order to operate. And microwave radios, waveguides and antennas emit energy when they transmit. However, onboard an offshore rig or other types of floating production, storage and offloading (FPSO) vessels flammable gasses are always present and have the possibility of becoming explosive in the presence of operating microwave radio equipment.

Until recently there were few solutions that could offer protection against the high chance of calamity associated with using microwave aboard an FPSO. Now there is a solution that has passed ATEX and IECEx Zone 1 certifications for mitigating the danger of explosive gasses: the BATS DVM ExP2 has passed both major safety body equipment requirements for operation in potentially explosive atmospheres.

Pressurized radome keeps flammable gas away from Eclipse radios
The BATS pressurized radome enclosed antenna aiming and tracking system (AATS) combined with one or two Aviat ODU 600s connected with a 0.9m or smaller antenna is the only microwave radio solution for potentially explosive atmospheric situations that is certified for use as per these two leading safety regimes. The system purges any potential flammable gas from the radome and once pressurized keeps any flammable gas out and away from the powered microwave radio.

Gas cannot get inside due to the positive pressure of the system. The only way gas could enter is if there is no longer positive pressure within the dome. In that case, everything in the dome is automatically shut off. The system is designed so that there is no possible way for gas to enter the system and any electronics to be active. All microwave and stabilization systems are plugged into a hardwire PDU/alarm system that automatically shuts power off at the source in the event of a loss of pressure.

Only antenna alignment system based on two technologies
Combined with its AATS capabilities to align microwave antennas onboard floating platforms to shore, a BATS-Aviat microwave radio antenna solution can stabilize the microwave signal on a vessel or platform as it moves—due either to sea motion or sway. This system uses two types of alignment technologies: GPS and Signal Quality Tracking Algorithms (SQTA).

With SQTA, the microwave radio beam is tested for the center of the beam, which is aimed directly at the center of the receiver. This algorithm runs continuously resulting in a dynamically aimed system through the BATS sync system, keeping the link on beam as much as possible as the ocean conditions change and move the floating platform. Systems that rely exclusively on GPS to accomplish microwave antenna alignment between ship and shore—and vessel to vessel—are very inexact, achieving lower quality links that may be off-center with only a portion of the signal strength and capacity of an on-beam signal.

In addition, in emergency shutdown (ESD) situations, it is unwise to have heavy reliance on GPS because if the floating platform is powered down, the GPS units will also lose power. A BATS-Aviat solution has its own internal power and using the signal tracking algorithm, it can maintain a last line of communication to shore or a companion rig when everything else onboard is shutdown.

For more information on the BATS-Aviat microwave radio antenna alignment solution, please download the datasheet.

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