Custom UPS software empowers more secure pipeline control

Server-shutdown protocols supported by real-time battery-life information.

By William Fox and John Ely August 11, 2017

Power protection and condition are vital for oil & gas installations. Power failures lead to lost time, inoperative equipment, and the possibility of safety issues arising. The industry relies on the uninterruptible power supply (UPS) to guard against unexpected power disruptions.

While UPS systems come in various forms and models, any oil & gas application requires some degree of customization. It might be as simple as adding an analog meter for quick visual reference, or there could be a need for a full-on tailored system that matches unique electrical requirements.

Many oil & gas industry applications, for instance, are in remote, rugged environments and hard-to-reach locations, away from populous areas. A remote pumping station, by nature, is not found in an enclosed facility or near other operations.

A remote installation may be exposed to wide temperature swings, excess humidity, and sources of corrosion, leading to more frequent equipment failures.

On the other hand, most UPS systems are meant to be installed and housed in a facility with electronics and other switchgear. The room may be climate-controlled, as is common with battery rooms. The production site is also likely to include process-control, lighting, and safety systems.

AMETEK Solid State Controls recently addressed a challenge one of its oil & gas industry customers faced. What began as a customization to support a single customer, is today a solution available to address industry-wide challenges of operating increasingly sophisticated equipment in remote locations.

Diagnosing a problem

In remote operations, when a power outage or severe power-quality deterioration does occur, pipelines and pumping systems are programmed to initiate safe network-shutdown procedures. The protocols involved are typically instanced on the various servers that monitor and control system parameters. Some users reported, however, that due to server errors, their systems in operation did not correctly follow the pre-determined powering-down protocols.

As part of their situation analysis, AMETEK engineers noticed that when the UPS approached the end of its backup-battery design life and eventual power loss neared, many-if not all-of the control-system mechanisms deployed at a pumping station or at a point along a pipeline malfunctioned. Moreover, they realized that the system failures were caused either by the servers not sending proper shutdown communications prior to the power loss, or by a complete communications shutdown afterward.

Deeming the situation unacceptable, the engineers warned that improper sequencing of pump-valve shutdown protocols could lead to valves not actuating, ruptured lines, or other possible serious consequences.

Finding a fix

AMETEK engineers determined that the UPS system could monitor the battery-time remaining and control server-shutdown protocols based on real-time information about true battery life. Without that critical information, system errors resulted and the servers lost power before the pump-system shutdown began. Calculating battery-time remaining is essential for creating dynamic protocols for safe-shutdown communications from control-system servers.

The additional software allows users to enter battery specifications. The system then calculates—in real time—the estimated battery-time remaining during the UPS backup operation (battery discharge cycles). The UPS communicates constantly with all servers in the circuit and if a backup-power situation arises, the UPS will determine when—and in what sequence—the servers are to power down.

The system also sends shutdown messages to the servers, allowing sufficient time for them to commence safe-shutdown procedures and eliminating errors caused by servers simply losing power. In the failsafe mode, the UPS will time-out servers based on a pre-determined time interval, eliminating premature server power failure.

Other system parameters and specification include:

  • Storage of up to 2,000 data events
  • User-defined alerts pertaining to data-log storage
  • Data retrieval over Ethernet, including the data log
  • Scheduled equalization of station batteries
  • Constant "heartbeat" monitoring of all servers
  • Control of shutdown time intervals for up to four groups of four servers
  • Specification of static IPs for all servers
  • Time-syncing the UPS to network-time protocol (NTP)
  • Network adapters for redundancy and signal isolation
  • Test and initiate server shutdown from the UPS front panel and Web interface
  • Data-log retrieval over TCP/IP using a web interface

Other features include network services over two Ethernet ports (Network Adapters 1 and 2) and additional functions for the UPS.

Network Adapter 1 allows a) viewing and retrieval of the data log over Ethernet, b) Modbus TCP messages, and c) system parameter and status viewing. The second adapter is for server shutdown, "heartbeat" messaging from the client running on the servers, testing shutdown from the front panel, synchronization of UPS time to NTP server, and simple-network management protocol (SNMP) messaging.

Both network adapters use web servers and associated web pages resident in each adapter’s software to facilitate presentation of UPS information and adapter management.

Final words

Because of the investigations outlined above, Ametek introduced a new UPS with failsafe backup power and control mechanisms. Developing a line of products to meet the very special needs of the customer is not a common practice, but AMETEK successfully met its customer’s  rigorous specifications and ended up with new hardware, software, and sustem design suitable for widespread industry use.

William Fox is a senior development engineer, and John Ely is a marketing manager with AMETEK Solidstate Controls.

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Original content can be found at Oil and Gas Engineering.