Reyrolle is the Siemens relay line for subtransmission, distribution and industry. The Argus family includes the 7SR10 and 7SR11 (non-directional) and 7SR12 (directional) overcurrent and earth fault relays, the self-powered 7SR45 for compact switchgear and MV/LV transformers, the 7SR2 range (7SR210/7SR220) and the 7SR242 Duobias transformer relay. They are configured with Reydisp Evolution.
What it is and where it is used
Reyrolle is a historic British protection brand that is now part of Siemens. Siemens presents it for subtransmission, distribution and industry, and it coexists with the SIPROTEC line. Reyrolle relays of the Argus family (7SR1) and the 7SR2 range are common in medium-voltage switchgear, compact units (RMU), distribution substations and industrial plants.
Each unit is identified by the model number (“7sr10”, “7sr11”, “7sr12”) and by the full order number (“7sr1004-3ka20-2ca0”). For the general picture, see protective relays.
Variants: 7SR10, 7SR11, 7SR12, 7SR45, 7SR210/220 and 7SR242
| Model | Application | Main difference |
|---|---|---|
| 7SR10 | Distribution and industry | Non-directional overcurrent and earth fault; IEC 60870-5-103, DNP3 or Modbus RTU protocols |
| 7SR105 | Motors | Motor relay of the 7SR10 platform |
| 7SR11 (Argus) | Feeders | Non-directional overcurrent and earth fault |
| 7SR12 (Argus) | Feeders | Adds voltage inputs: directional and voltage |
| 7SR17, 7SR18, 7SR157, 7SR158, 7SR191 | Motor, differential, synchronism check, voltage and frequency, capacitors | Other members of the 7SR1 range |
| 7SR45 | Compact switchgear and MV/LV transformers | Self-powered or dual-powered, non-directional |
| 7SJ45 / 7SJ46 (SIPROTEC easy) | Compact switchgear and MV feeders | Numerical overcurrent of the previous generation; the Siemens site now refers the 7SJ46 to the 7SR45 |
| 7SR210 / 7SR220 (7SR21, 7SR22) | Feeders | 7SR210 non-directional, 7SR220 directional; arc detection |
| 7SR224 | Recloser control | Independent reclose sequences for phase, earth and sensitive earth |
| 7SR242 Duobias | Two-winding transformers | Percentage differential and restricted earth fault |
The self-powered 7SR45 and the older 7SJ45 and 7SJ46
The Reyrolle 7SR45 is the Siemens self-powered overcurrent and earth fault relay: it takes its energy from the current transformers themselves, so it protects even if the switchgear has no battery or auxiliary supply. In its dual-powered version it uses the auxiliary supply when present and switches to the current transformers when it is missing. Siemens presents it with four current inputs, up to four configurable binary inputs and four binary outputs, a pulse output, programmable LEDs, an optional flag indicator, a display and a front USB port. Its functions are definite-time and inverse-time, non-directional.
Its typical application is compact switchgear (RMU) and MV/LV distribution transformers. Before it, Siemens offered the SIPROTEC easy 7SJ45 and 7SJ46, numerical overcurrent relays still found in older switchgear; the 7SJ46 page on the Siemens site now refers to the 7SR45. See compact medium-voltage substation.
Main functions
According to the Siemens Reyrolle product catalog:
| Function | ANSI | Models |
|---|---|---|
| Instantaneous and time-delayed phase and ground overcurrent | 50/51, 50G/N, 51G/N | All (guide) |
| Directional phase and ground overcurrent | 67/50, 67/51, 67G | 7SR12, 7SR220, 7SR224 (guide) |
| Thermal overload, negative sequence, broken conductor | 49, 46NPS, 46BC | 7SR2 and optional in 7SR242 (49) |
| Breaker failure | 50BF | 7SR2, 7SR242 (guide) |
| Transformer differential with restraint | 87 | 7SR242 (guide) |
| High-impedance restricted earth fault | 64H | 7SR2, 7SR242 (guide) |
| Under and overvoltage, neutral displacement | 27/59, 59N | 7SR220, 7SR224, optional in 7SR242 |
| Reclosing | 79 | 7SR224 and other models depending on the order code (guide) |
| Trip and close circuit supervision | 74TC/CC | 7SR2, 7SR242 (guide) |
The 7SR242 also includes second and fifth harmonic blocking and optional overexcitation; the 7SR210/220 add arc detection (50AFD), cold load pickup and CT supervision.
Communications and integration
Siemens states that Reyrolle relays use IEC 60870-5-103, Modbus RTU, DNP3 and IEC 61850. The 7SR10 and the 7SR45 work through a front USB port and a rear RS-485 (the 7SR45 with IEC 60870-5-103 and Modbus). In models with IEC 61850, the communication is added with the EN100 module and the IEC 61850 versions include PRP, HSR and RSTP redundancy. Configuration, event reading and fault records are done with Reydisp Evolution. See IEC 60870-5-103 and IEC 61850 overview.
Frequently asked technical questions
- Order code: the full number (for example 7SR1004-3KA20-2CA0) defines the hardware; a common mistake is to assume functions that the variant does not include.
- Drivers and USB connection with Reydisp: the software must match the version of the unit.
- 7SR45 with no indication after a trip: being self-powered it depends on the available current; the local or remote flag is the reference.
- Arc detection in the 7SR210/220: it is combined with light sensors and overcurrent; its use is defined in the arc flash study.
- Eight setting groups in the 7SR2 range: a group change by input or by communication leaves settings active that differ from the expected ones.
If your unit is no longer manufactured
The 7SJ45 and 7SJ46 are from a previous generation. Moving to a 7SR45 is not a matter of copying settings: the available functions, the trip method, the inputs and outputs and the communication change, and you must check that the minimum current of the switchgear is enough to power the relay. We review the study, design the change and test the new unit; see engineering design and studies.
How we help
At Tiza Group we configure Siemens relays remotely, worldwide, with a backup before and after the change. See remote configuration of Siemens relays and remote relay configuration. If the relay has already tripped and it is not clear why, we quote the analysis of the event in trip review, or write to us through contact.
Related guides
- Protective relays
- Phase and ground overcurrent protection
- Radial feeder protection scheme
- Medium-voltage switchgear
- Distribution transformer
References
- IEEE C37.2, electrical power system device function numbers.
- IEC 60255 (series), measuring relays and protection equipment.
- Siemens, Reyrolle product catalog and catalogs of the 7SR10, 7SR45, 7SR11/7SR12 and 7SR242 Duobias.
Frequently asked questions
What is the difference between the 7SR11 and the 7SR12?
Both are Argus overcurrent and earth fault relays. The 7SR11 is non-directional; the 7SR12 adds voltage inputs for directional protection and voltage functions. Both come in variants with one and four current inputs.
What is a 7SR1004-3KA20-2CA0?
It is an order number (MLFB code) of a relay on the 7SR10 platform. Each position of the code defines options such as inputs, outputs, power supply, case and communications. To know exactly what a unit has, compare the code on its nameplate with the ordering table in the Siemens catalog.
Does the 7SR45 need auxiliary power?
Not necessarily. The 7SR45 is self-powered from the current transformers, or dual-powered (CTs plus optional auxiliary). Siemens aims it mainly at compact switchgear (RMU) and MV/LV transformers, where there is not always a battery. In older switchgear it performs the role formerly filled by the SIPROTEC easy 7SJ45 and 7SJ46.