CSC relays are the protection and control line of Beijing Sifang Automation (SIFANG), a Chinese manufacturer that reaches Latin America with transmission, generation and EPC projects. Among the relays are the CSC-103, a line differential IED; the CSC-211, feeder protection and control for networks below 110 kV; the CSC-326, used on transformers; and the CSC-150, busbar differential protection.
What it is and where it is used
CSC relays are the protection, automation and control line of Beijing Sifang Automation (SIFANG), a Chinese manufacturer of power system equipment. In Latin America they appear mainly in transmission projects, hydro and solar plants, and substations built by Asian EPC contractors. Among the models are the CSC-103, the CSC-211, the CSC-326 and the CSC-150.
For whoever receives a substation with this equipment, the difficulty is usually not the protection itself but the documentation, the configuration software and the integration with a SCADA from another brand. For the general picture, read protective relays.
Variants: CSC-103, CSC-211, CSC-326 and CSC-150
| Model | Application | Main difference |
|---|---|---|
| CSC-103 | High and extra high voltage line | Line differential IED, with a channel between terminals |
| CSC-211 | Line or feeder below 110 kV | Protection, measurement and control; overcurrent, ground and reclosing, for a neutral not solidly grounded |
| CSC-326 | Transformer | Model found in transformer panels; its scope is confirmed in the product guide |
| CSC-150 | Busbars | Busbar differential with stabilization, breaker failure and bus coupler overcurrent supervision |
Sifang’s public online information is scarce and much of its product guides circulates in third-party copies. For that reason, gather the original project documentation before any work.
Main functions
| Function | ANSI | Where it appears |
|---|---|---|
| Line differential | 87L | CSC-103 (guide) |
| Distance (backup, depending on the model) | 21 | Line relays (guide) |
| Phase and ground overcurrent | 50/51, 50N/51N | CSC-211 (guide) |
| Reclosing | 79 | CSC-211 and line relays (guide) |
| Transformer differential | 87T | Transformer relays (guide) |
| Busbar differential and breaker failure | 87B, 50BF | CSC-150 (guide) |
The exact functions of each unit depend on the order code and the software version; the table summarizes what the documentation of each family describes.
Communications and integration
The most recent CSC IEDs integrate over IEC 61850, with MMS to SCADA and GOOSE between units; which edition and which services each one supports is confirmed in its conformance statement (PICS). Older installations also use IEC 60870-5-103 and serial protocols. The CSC-103 also needs its communication channel between terminals, which is designed and tested as part of the scheme. Related reading: IEC 61850 and SCL files.
Documentation and standards of Chinese origin
CSC relays are designed on the standards of the Chinese power sector, and understanding that framework helps in reading their manuals. The CSC-103 product guide that circulates in third-party copies shows version V1.06, dated August 2020, and rights held by Beijing Sifang Automation; it is a useful reference but does not replace the manual of the installed version. For questions to the manufacturer, the corporate site (sf-auto.com) publishes a technical support email.
- IEC 61850 is published in China as DL/T 860. Chinese texts list DL/T 860 as the equivalent of IEC 61850. For example, DL/T 860.5-2006 is declared identical (IDT) to IEC 61850-5:2003. DL/T 860.6-2012 carries the title of substation communication configuration for IEDs. It corresponds to the configuration language of part 6 and is the basis of the ICD, CID and SCD files. If the project arrived with Chinese documentation, those terms are the same as in the international series.
- GB/T 32890-2016 describes the application model of DL/T 860 to relay protection: configuration, models and services for engineering and application in new substations. Ask the manufacturer for the data model and the PICS of the installed version before integrating the unit into a SCADA from another brand.
- GB/T 14285 is the reference standard for relay protection and security automation, and the channel standard DL/T 364 also cites it.
- DL/T 364, on protection communication channels, adds in its revision a ban on a line differential channel using the SDH ring self-healing switching function, the requirement for protections with dual channels, and the definition of the 2 Mbit/s optical interface. The description we saw of that revision is an English summary from a standards site; the current text should be consulted in the official edition.
Line differential communication channel
The CSC-103 compares the currents at both terminals, so it depends on the channel having a known and symmetrical delay. The technical literature on differential protection notes that delay asymmetry arises mainly when transmit and receive follow different routes in a telecommunications network; for that reason, schemes over multiplexed networks require both directions to use the same path. When the network switches route automatically, the delay changes without notice and the protection may block or, in the worst case, measure incorrectly. A 2021 conference paper on connecting protections directly to the 2 Mbit/s optical interface of transmission equipment reports an appreciable delay reduction compared with the scheme using intermediate electro-optical converters. For the CSC-103, the practical conclusion is to ask whoever operates the communications network for the route, the interface and the measured delay, and not to assume them.
Busbars and dead zones with the CSC-150
A technical paper on 220 kV busbar protection cites the CSC-150 among the domestic busbar protections of its category, together with other manufacturers. In this type of scheme, the zone between the bus coupler and its current transformers is the typical dead-zone case: with the coupler breaker closed and a fault in that zone, poorly designed logic can trip a healthy section. The literature proposes using the currents on both sides of the coupler as a criterion to avoid that trip. When a substation is expanded with the CSC-150, checking that logic and the disconnector assignment is part of commissioning, and it is defined by the installation scheme, not by the generic manual.
Frequently asked technical questions
- Documentation for the Sifang CSC-103 and CSC-211 relays: the valid documentation is that of the project and the software version. A guide downloaded from another project may not match your unit.
- The CSC-103 blocks the differential on channel failure: check the channel (fiber, multiplexer, delays and asymmetry) before touching settings. Related reading: multiplexer and fiber optic network.
- Integrating a CSC into a SCADA from another brand: the ICD/CID file and the signal mapping must come from the project; if they do not exist, they are rebuilt from the unit.
- Language of the interface and settings: some units arrive with documentation or menus in Chinese or English; agree with the manufacturer on the local-language version before commissioning.
- Busbar differential in expansions: adding a bay to the CSC-150 requires reviewing inputs, CT ratios and disconnector logic.
If your unit is no longer manufactured
If a CSC is left without local support, the decision between keeping it and replacing it depends on spare parts, available documentation and the scheme. We review the study, design the replacement with the brand the client chooses, and test the complete scheme; the scope is described under engineering design and studies.
How we help
At Tiza Group we configure and review protective relays remotely, worldwide, including those from manufacturers with little local presence, and we rebuild the IEC 61850 configuration when the project did not deliver it. The scope is described under remote relay configuration and IEC 61850. If a CSC tripped and the reason is unclear, we quote the trip analysis. Write to us through contact.
Related guides
- Line differential protection 87L
- Busbar differential protection 87B
- Transformer differential protection 87T
- Multiplexer and fiber optic network
- IEC 61850: overview
- SEL-411L relay
- GE Multilin D60 and L90 relays
- NR Electric PCS-9611, PCS-931 and PCS-978 relays
- Toshiba GRD110, GRT100, GRL100, GRZ100 and GR-200 relays
- Mitsubishi MELPRO-D, Hyundai HiMAP and LS GIPAM relays
References
- IEC 61850 (series), communication networks and systems for power utility automation.
- IEC 60255 (series), measuring relays and protection equipment.
- IEEE C37.2, device function numbers for power systems.
- DL/T 860 (series), the Chinese equivalent of IEC 61850; GB/T 32890-2016; DL/T 364 (protection channels).
- Beijing Sifang Automation (SIFANG), corporate site and product guides for the CSC-103, CSC-211 and CSC-150.
Frequently asked questions
What is the Sifang CSC-103 relay?
It is a line differential protection IED from Beijing Sifang Automation, documented in its product guide. It is applied on high and extra high voltage lines, with a communication channel between the terminals, normally direct optical fiber or a multiplexer.
What is the Sifang CSC-211 for?
It is a numerical line or feeder protection, measurement and control unit. Its documentation presents it for systems below 110 kV with a neutral that is not solidly grounded, with overcurrent, ground fault and reclosing, among other functions.
Where can I get the Sifang CSC-103 or CSC-211 manual?
Sifang supplies manuals and product guides by project and software version. Before requesting them, note the full model, the software version and the serial number: functions and IEC 61850 configuration change between versions.