Remote Control Overrides let you open or close a valve or turn a Pump Station or Compressor Station on or off, based on conditions that exist on other nodes or legs elsewhere in the system.

For example, if there is an increase in demand at the downstream end of a natural gas transmission system due to a cold front, you might turn compressor stations on at the upstream end of the system as soon as you detect the increased flows at the downstream end in anticipation of the increase in throughput and line pack that will be required even though it may be several hours before the effect is actually felt on the upstream end.

Or for a crude oil pipeline, you might have a line from an oil well feeding into a storage tank, but when the tank reaches its capacity, you want to close one valve to stop the flow into the tank, and open another one to open a bypass line, perhaps even turn on a pump to empty the tank.

For example, in the two images shown, when the tank volume reaches 90% of the tank capacity, we use Remote Control Overrides to close the valve at the top of the tank, open the bypass valve, and turn on the pump to empty the tank. When the tank has been emptied and the volume falls below 10% capacity, the Remote Control Overrides automatically turn the pump off, close the bypass valve, and open the valve at the top of the tank. All of this happens automatically using remote control overrides, without needing to create any schedules.

You could of course duplicate this by creating schedules, but then you would have to know ahead of time at what time the tank will be full, when it will be empty, and you would have to repeat the schedules for every full/empty cycle.

Using Remote Control Overrides is much easier since they don’t rely on a specific time, but rather trigger when certain thresholds are reached, and in this case, the cycle of the tank filling up and being emptied will repeat itself indefinitely even with varying injection and withdrawal rates.

Remote Control Overrides work in Steady State, Sequential Steady State, and Transient, and are supported in both Gas and Liquids Modes.

There are four Remote Control Overrides currently supported:

• Remote Control Valve Open Override
• Remote Control Valve Close Override
• Remote Control Compressor or Pump Station On Override
• Remote Control Compressor or Pump Station Off Override

Any or every valve in the system, or pump or compressor station can have individual remote control overrides defined.

For each one of these overrides that you want to implement, you must go to the specific valve or station element, define what other element and variable will be used to test against, for example a specific node pressure or check meter flow rate, and define the upper or lower threshold that the value must reach for the override to trigger.

The value used to open a valve does not have to be the same value used to close the valve. For example, you might use the pressure at one node to trigger a valve to open, but use the flow rate through a process plant to trigger the same valve to close. The same applies to pump or compressor stations.

Remote Control Overrides add a whole new dimension to how you can control your models, and let you automatically control valves and compressor or pump stations using current conditions on the pipeline, rather than having to create cumbersome time schedules that can easily be out of sync with the actual pipeline operation.

Remote Control Overrides are available to all NextGen users and do not require additional licensing.