The Siemens SIPROTEC 4 7SJ61, 7SJ62, 7SJ63 and 7SJ64 are multifunction overcurrent relays for feeders, motors and transformers at medium and high voltage. They are configured with DIGSI 4. Siemens already marks the 7SJ64 as a phase-out product and its current line is SIPROTEC 5, so many of these units are in maintenance or replacement stage.
What it is and where it is used
The Siemens SIPROTEC 4 7SJ6 relay groups four models found in thousands of switchgear cubicles: 7SJ61, 7SJ62, 7SJ63 and 7SJ64. They are multifunction numerical overcurrent relays of the SIPROTEC 4 family, the generation before SIPROTEC 5. They are used as main protection of medium-voltage feeders, as backup in high-voltage bays, and in industrial plants for motors and transformers. This is complemented by SIPROTEC 4: DIGSI 4, matrix and CFC.
They are also identified by their order code, such as 7SJ6215 or 7SJ6225: the first digits identify the model and the rest describe auxiliary voltage, inputs and communications.
If you are looking for the general picture of this type of device, start with the guide on protective relays.
Variants: 7SJ61, 7SJ62, 7SJ63, 7SJ64 and 7SJ80
| Model | Application | Main difference |
|---|---|---|
| 7SJ61 | Feeders and small motors | Current inputs only: phase and ground overcurrent |
| 7SJ62 | Ring feeders, transformers, motors | Adds voltage inputs: directional, voltage and frequency |
| 7SJ63 | Bays with local control | More inputs and outputs, graphic display and control of breaker and disconnectors |
| 7SJ64 | Feeders with transfers or generation | Adds synchronism check (25) |
| 7SJ80 | Medium-voltage feeders | Not SIPROTEC 4: it belongs to SIPROTEC Compact, the compact line that coexisted with the 7SJ6 |
The exact set of functions depends on the order code. Two 7SJ62 units can have different functions.
Main functions
| Function | ANSI | What it provides |
|---|---|---|
| Instantaneous and time-delayed phase and ground overcurrent | 50/51, 50N/51N | Main protection against short circuits (guide) |
| Directional overcurrent (7SJ62 onward) | 67, 67N | Selectivity in rings (directional units) |
| Automatic reclosing | 79 | Overhead networks (guide) |
| Voltage and frequency | 27, 59, 81 | Abnormal system conditions |
| Breaker failure | 50BF | Backup if the breaker does not open (guide) |
| Thermal overload | 49 | Cables, transformers and motors (guide) |
| Synchronism check (7SJ64) | 25 | Safe closing between two sources (guide) |
SIPROTEC 4 relays include programmable logic (CFC), fault recording and an event list.
What the 7SJ62/64 manual says
The 7SJ62/64 manual (edition 08.2016, firmware V4.9) makes it possible to pin down several points that are often confused:
- Application scope. Siemens presents it for lines in networks with grounded, low-resistance grounded, isolated or compensated neutral, radial or ring, with infeed at one or several ends. It also presents it with motor protection for asynchronous machines of any size. It also offers it as backup for differential protection of lines, transformers, generators, motors and busbars at all voltage levels. On this point, read Siemens 7SK82, 7SK85 and 7SK80 relays.
- Overcurrent basis. Three definite-time stages and one inverse-time stage for phases and for ground, with curves from several standards (IEC and ANSI), one user-defined characteristic and two logarithmic inverse ones. Depending on the version ordered, it is complemented with directional, breaker failure and sensitive ground fault detection, directional or not.
- Cold load. Dynamic switching of the overcurrent settings when a cold load condition is recognized, detected by the breaker position or by a current threshold.
- Intermittent ground faults. An optional function detects and accumulates transient ground faults and trips after a configurable total time. A directional version trips after an adjustable number of restrikes.
- Ground fault direction. With zero-sequence quantities (I0, V0) or by the watt-metric method.
- Flexible functions. Up to 20 customizable protection functions, three-phase or single-phase, on any calculated or measured quantity, with configurable pickup and dropout delays. The manual uses that function in a reverse power protection example.
- Fault locator. Calculates the distance in ohms (primary and secondary) and in kilometers or miles; it supports up to three line sections.
- Synchronism and reclosing. Before closing after a three-pole trip, the 7SJ623, 7SJ624, 7SJ625, 7SJ626 and 7SJ64 can check voltage or synchronism. Single-shot or multi-shot reclosing, with different dead times for the first and following attempts and separate programs for phase and ground faults.
- Recording. Events and data of the last 8 system faults, with instantaneous values of up to 20 s in total, and long-term minimum, maximum and average values.
- RTD. An additional interface, only on the 7SJ64, connects an RTD box for external ambient or coolant temperatures.
This explains why two 7SJ62 units with different order codes are not interchangeable: the suffix changes functions such as synchronism check, sensitive ground and communication modules.
Which communication modules it accepts
According to the same manual, the basic protocol of the system port is IEC 60870-5-103, which is also used to integrate them with SINAUT LSA and SICAM. The EN100 module integrates them into 100 Mbit Ethernet networks with IEC 61850, PROFINET or DNP3 TCP, and DIGSI, GOOSE messages between relays and the connection to a SICAM I/O unit pass through that same port. As an alternative, there is fieldbus coupling with PROFIBUS FMS (DIN 19245), PROFIBUS DP, DNP3 and Modbus, the latter without all the possibilities of FMS; and there is a redundant IEC 60870-5-103 interface. See IEC 61850 overview and GOOSE.
Communications and integration
The 7SJ6 units have service and system ports that accept interchangeable communication modules. Depending on the module installed, the unit speaks IEC 60870-5-103, PROFIBUS, DNP3, Modbus or IEC 61850 through an Ethernet module. The IEC 61850 edition depends on the firmware and the module, so to integrate them into a new system both must be checked.
Configuration, settings and IEC 61850 files are handled with DIGSI 4. Oscillography is read with SIGRA or exported as COMTRADE.
Frequently asked technical questions
- 7SJ62 and 7SJ64 manuals: Siemens publishes the SIPROTEC 4 manuals by model and by version. The manual for the exact version is best, because functions changed between versions.
- DIGSI 4 does not recognize the unit: almost always the device file is missing or the DIGSI version does not match the firmware.
- Communication with SCADA: the same 7SJ62 can have different modules. Before changing the protocol, confirm which module it has.
- Cybersecurity: Siemens publishes security advisories that include SIPROTEC 4 devices. Check whether they apply to your firmware and your network.
If your unit is no longer manufactured
Siemens already identifies the 7SJ64 as a phase-out product, and its current protection line is SIPROTEC 5 (for example, the SIPROTEC 7SJ85) together with the compact range. Migrating is not just swapping the box: the settings and CFC logic must be translated, the input and output wiring reviewed, the SCADA integration redone and the new unit tested. We do it in parts: remote configuration of the new unit, retrofit design and commissioning tests.
How we help
At Tiza Group we configure and review SIPROTEC 4 and SIPROTEC 5 relays remotely, worldwide, based on the study and the approved settings, with a backup before and after the change. See the scope in remote configuration of Siemens SIPROTEC relays. If your 7SJ62 tripped and it is not clear why, we quote the trip analysis. If you are going to replace the 7SJ6 line, we do the design of the change in engineering design and studies. Write to us through contact.
Related guides
- Phase and ground overcurrent protection
- Automatic reclosing 79
- Radial feeder protection scheme
- COMTRADE files
- SIPROTEC 4: DIGSI 4, configuration matrix and CFC
- Siemens 7SK82, 7SK85 and 7SK80 Motor Protection Relays
References
- IEEE C37.2, device function numbers.
- IEC 61850 (series) and IEC 60870-5-103.
- Siemens, SIPROTEC 4 catalog and product pages for the 7SJ62 and 7SJ64.
- Siemens ProductCERT, SIPROTEC 4 security advisories.
Frequently asked questions
What is the difference between the 7SJ61, 7SJ62, 7SJ63 and 7SJ64?
All four are SIPROTEC 4 overcurrent relays. The 7SJ61 has current inputs only; the 7SJ62 adds voltage inputs and directional functions; the 7SJ63 adds more inputs and outputs and front-panel control of switching devices; the 7SJ64 adds synchronism check. The exact version is read from the order code on the nameplate.
Which software configures a SIPROTEC 7SJ62?
DIGSI 4, the Siemens tool for the SIPROTEC 4 family. You need the DIGSI version and the device file that match your firmware. DIGSI 5 is for the SIPROTEC 5 family and does not open SIPROTEC 4 devices.
Is the 7SJ64 still manufactured?
Siemens identifies it on its page as a phase-out product. For units of the 7SJ6 line, check the status of each model with the manufacturer and plan the migration to SIPROTEC 5 when spare parts or support run short.