Siemens SICAM PAS, SICAM SCC and WinCC OA SCADA

Short answer

SICAM PAS is Siemens' substation automation system: it collects data from relays and controllers over IEC 61850, IEC 60870-5-101/103/104, DNP3, Profibus DP or Modbus and passes it to the control center. SICAM SCC is its operator HMI, built on the SIMATIC WinCC platform. WinCC OA (Open Architecture) is Siemens' scalable SCADA platform, with IEC 61850, IEC 60870-5-104 and DNP3 drivers, used in control centers and large systems.

What they are and where they are used

Siemens has several software products for operating substations, and they are easy to confuse. SICAM PAS (Power Automation System) is the substation automation system: it talks to the relays, controllers and RTUs, processes the information and passes it to the control center. SICAM SCC is the operator HMI installed on top of it. WinCC OA (Open Architecture) is Siemens’ SCADA platform for large, distributed systems. They are found in medium, high and extra-high voltage substations, in generation plants and in industry. The components, redundancy, backup center and operator screens are treated in Control Center Design.

For the general concept, see substation SCADA and HMI systems.

Variants: SICAM PAS, SICAM SCC, WinCC and WinCC OA

Product	Function	Main feature
SICAM PAS	Substation automation, gateway	Modular and scalable; applications can be spread across several computers
SICAM PQS	Central archive of fault records and power quality data	Receives data over IEC 61850 and IEC 60870-5-103; imports COMTRADE and PQDIF
SICAM SCC (version 10)	Substation operator HMI	Built on SIMATIC WinCC; compatible with SICAM 8
SIMATIC WinCC	Industrial HMI/SCADA platform	Base on which SICAM SCC runs
WinCC OA (3.18, 3.19, 3.20…)	Distributed, large-scale SCADA	Windows and Linux, redundancy, drivers licensed separately

Main characteristics

SICAM PAS: Siemens describes it as an automation system to monitor and control the equipment and processes of the substation, with built-in testing and diagnostics for commissioning and maintenance.
SICAM SCC: substation screens, alarm and event lists, select-before-operate control and an operation log. It can be used as an add-on to SIMATIC WinCC.
WinCC OA: distributed architecture, redundancy and documentation per version. Its drivers (IEC 61850, IEC 60870-5-104, DNP3) are licensed separately.
Typical architecture: a SICAM PAS server (sometimes redundant) in the substation control room, one or more SICAM SCC stations for the local operator and a link to the regional control center. In larger systems, WinCC OA brings several substations together in one SCADA.

Communications and integration

SICAM PAS: according to Siemens, it exchanges data over IEC 61850, IEC 60870-5-101, 103 and 104, DNP V3.0, PROFIBUS DP and Modbus.
WinCC OA: IEC 61850 client, IEC 60870-5-101 (serial) and 104 (TCP/IP), DNP3 level 3+ as master (also in redundant systems, if the outstation accepts two connections) and Modbus TCP.
In most substations, the relays reach SICAM PAS over IEC 61850 and the control center receives the data over IEC 60870-5-104 or DNP3. Each protocol has its own guide: IEC 61850 MMS, IEC 60870-5-104 and DNP3.

Frequently asked technical questions

WinCC OA and configurator documentation: Siemens publishes the documentation per version; a project must be opened with the version it was created in, or migrated.
SICAM PAS does not see a relay: outdated SCL file, wrong IP address or IEC 61850 reports not enabled; see SCL files.
A signal reaches the SCC but not the control center: the mapping to IEC 60870-5-104 or DNP3 is independent of the HMI mapping.
Licenses: PAS, SCC and WinCC OA are licensed separately; adding points may require a new license.
Migrating old versions: the change of operating system, licenses and databases has to be planned.

What the SICAM SCC manual says

The SICAM SCC V9.05 manual (November 2019 edition, published by Siemens in English) defines SICAM SCC as the human-machine interface of SICAM PAS/PQS systems, SICAM RTUs, IEC 61850 devices, IEC 60870-5-104 devices and SICAM SAS. SICAM SAS consists of the SIMATIC WinCC visualization system and the SICAM SCC components: the graphic object library, the alarm system extension, the wizards (PAS, IEC, TEA-X and Global), the SICAM functions and the normalization DLLs. It also includes the protocol packages and SICAM Valpro, which evaluates measured-value and counter files.

Technical details of the manual that are easy to miss:

Graphic objects with process states. The library includes switchgear objects with their dynamic properties already defined. A circuit breaker, for example, shows the states closed, open, intermediate position, fault position, not updated, “PAS not OK”, bay blocked, substituted and telecontrol blocked. That list of states is why the screen can tell the operator more than just “open” or “closed”.
Chronological order. The alarm system extension makes sure data are recorded and archived in the correct chronological order.
Topological coloring. A whole chapter is devoted to coloring the single-line diagram according to the state of the network.
Client-server systems and redundancy. A SICAM SCC system can be redundant; if one of the two servers fails, the clients switch automatically to the active server. The manual states that a redundant SICAM PAS system or SICAM RTUs are supported.
Web client. WinCC Web Navigator allows the process diagrams to be published.
System time. One chapter covers the system time, and another the conversion of projects from earlier versions.
Platform. SICAM SCC V9.05 is a 32-bit application that is combined with specific versions of SIMATIC WinCC (V7.3, V7.4 SP1 and V7.5) and with specific Windows operating systems; the combination must be checked in the manual before installing.

This manual belongs to an earlier generation than the one Siemens now presents as SICAM SCC version 10, compatible with SICAM 8. The public sources consulted give no end-of-life date for SICAM PAS and no successor. The lifecycle status of each reference is checked by its article number in the Siemens Industry Mall or with manufacturer support. A SICAM PAS function update number appeared as an active product, but that does not mean the status of the whole line.

Points of attention in commissioning and maintenance

Version compatibility. SICAM SCC has a chapter of its own on the different SICAM PAS versions; before upgrading either one, check which combination is compatible.
One mapping per destination. What is published to the HMI and what is sent to the control center over IEC 60870-5-104 or DNP3 are independent mappings; a signal that shows on screen does not prove that it reaches the control center.
Time. If the server, the relays and the control center do not share a time reference, the sequence of events loses its value; see time synchronization in substations.
Licenses. PAS, SCC and WinCC OA are licensed separately, and so are the WinCC OA drivers; adding points may require a new license.
Migration. Changing the operating system, the WinCC version or the database engine is planned with a full backup and a control test. These checks belong in FAT and SAT testing.

How we can help

At Tiza Group we configure substation automation and HMI: databases, IEC 61850, IEC 60870-5-104 and DNP3 mappings, screens, alarms and point-to-point tests with the control center, on site in Colombia (or elsewhere on request) or remotely, worldwide. The related services are SCADA integration and gateways and control, protection and communications configuration. To modernize an existing system, see engineering design and studies. Write to us through the contact page. If the signal exists in the relay but does not show up in the SCADA, the checking chain is in Case: the signal is in the relay but not in SCADA.

References

IEC 61850 (series); IEC 60870-5-101, 103 and 104; IEEE 1815 (DNP3).
Siemens, SICAM PAS and SICAM SCC product pages, SICAM SCC upgrade catalog and WinCC OA documentation (IEC 61850 and DNP3 drivers, and licensing).

Frequently asked questions

What is the difference between SICAM PAS and SICAM SCC?

They do different jobs and usually run together. SICAM PAS is the automation system: it talks to the field devices and to the control center. SICAM SCC is the operator interface: screens, alarms, events and control for the substation operator.

Is SICAM SCC still current?

Siemens lists upgrades from earlier SICAM SCC versions to version 10 in its catalog, which shows the product is still maintained. For a new project, confirm the version and its compatibility with the chosen automation system with the manufacturer.

Does WinCC OA support IEC 61850?

Yes, as an IEC 61850 client driver with an additional license, according to the WinCC OA documentation. It also documents IEC 60870-5-101 and 104 drivers, DNP3 as master and Modbus TCP.