SIS and ITCC as well as unit control

This post was last edited by ssln123 on 2016-10-11 at 15:57. SIS is used to assess the risk level of a device in order to determine whether it is necessary to implement it. ITCC is a comprehensive protection system for turbine and compressor systems, and it is required for large-scale units. 3500 is a status monitoring system, and it is also essential for large-scale units. Generally, 3500 is not sufficient; the ITCC also handles functions such as turbine speed control and anti-surge control. If a SIS is in place, the ITCC can use a system that is integrated with the SIS, while in the absence of a SIS, a system that meets the required specifications should be chosen. 3500 is merely one component of the ITCC.

This issue has been discussed in many posts before; you can search for it.

Thank you for the answer. I searched through many posts these past few days and finally understood it!

The ITCC (Integrated Turbine & Compressor Control System) is a comprehensive control system for compressors; it integrates functions such as speed control and extraction steam control for steam turbines, anti-surge control for compressors, performance control, decoupling control, load distribution control – all of which are specific to such units – as well as self-protection and interlock logic controls. The ITCC itself already possesses the ESD safety interlock level. For air separation units, if ESD is installed for the process controls other than the compressor units, the same controller can be shared with the ITCC provided that its load rate meets the requirements. The ITCC is formed by combining 3500 and TRICON in order to achieve control, regulation, and interlock protection of the on-site compressor units. (3,500 pairs of vibration displacements are monitored; TRICON controls and regulates the unit as well as issuing interlock commands.)

ITCC has no connection to SIS. ITCC is unit control and does not have the safety level requirements of SIS. The reason why ITCC and SIS can be combined is that the controllers used in ITCC meet the safety requirements and can be used in SIS systems. In short, controllers can be used for ITCC and SIS, but ITCC cannot be used for SIS.

You really know a lot about this; after hearing you explain, I have a deeper understanding of these concepts – that’s great. I’d also like to ask you: is my understanding of that passage correct?

Hello, it’s really lucky to meet you; you allow me to learn so much! First of all, thank you here for your perfect answer! There is another point that I’m not clear about, and I would like to ask for your opinion. Here is an example of this issue: for instance, a centrifugal compressor along with its associated auxiliary systems (lubricating oil system, dry gas seal system, etc.). The system interlocks related to the compressor – such as those triggered by changes in temperature, vibration, or displacement – as well as the switching between high and low pressure in the lubricating oil pump – are all handled within the ITCC system, or is a SIS system used for such interlocked shutdowns? The second question is: if it is not a cascade in the compressor system but rather a cascade based on process parameters that requires the compressor to stop, should the SIS send a stop signal or should it go to the ITCC to initiate a cascaded shutdown?

Hello, it’s really lucky to meet you; you allow me to learn so much! First of all, thank you here for your perfect answer! There is another point that I’m not clear about, and I would like to ask for your opinion. Here is an example of this issue: for instance, a centrifugal compressor along with its associated auxiliary systems (lubricating oil system, dry gas seal system, etc.). The system interlocks related to the compressor – such as those triggered by changes in temperature, vibration, or displacement – as well as the switching between high and low pressure in the lubricating oil pump – are all handled within the ITCC system, or is a SIS system used for such interlocked shutdowns? The second question is: if it is not a cascade in the compressor system but rather a cascade based on process parameters that requires the compressor to stop, should the SIS send a stop signal or should it go to the ITCC to initiate a cascaded shutdown?

Hello, it’s really lucky to meet you; you allow me to learn so much! First of all, thank you here for your perfect answer! There is another point that I’m not clear about, and I would like to ask for your opinion. Here is an example of this issue: for instance, a centrifugal compressor along with its associated auxiliary systems (lubricating oil system, dry gas seal system, etc.). The system interlocks related to the compressor – such as those triggered by changes in temperature, vibration, or displacement – as well as the switching between high and low pressure in the lubricating oil pump – are all handled within the ITCC system, or is a SIS system used for such interlocked shutdowns? The second question is: if it is not a cascade in the compressor system but rather a cascade based on process parameters that requires the compressor to stop, should the SIS send a stop signal or should it go to the ITCC to initiate a cascaded shutdown?

Hello, it’s really lucky to meet you; you allow me to learn so much! First of all, thank you here for your perfect answer! There is another point that I’m not clear about, and I would like to ask for your opinion. Here is an example of this issue: for instance, a centrifugal compressor along with its associated auxiliary systems (lubricating oil system, dry gas seal system, etc.). The system interlocks related to the compressor – such as those triggered by changes in temperature, vibration, or displacement – as well as the switching between high and low pressure in the lubricating oil pump – are all handled within the ITCC system, or is a SIS system used for such interlocked shutdowns? The second question is: if it is not a cascade in the compressor system but rather a cascade based on process parameters that requires the compressor to stop, should the SIS send a stop signal or should it go to the ITCC to initiate a cascaded shutdown?