Functional block diagram of the S24/HZ relay
General presentation
The S24/HZ (V7) relay is a digital earth or restricted earth fault differential relay (high impedance). It is intended for the protection of busbars, transformers, generators and motors, where fast tripping in the event of a fault is required, with high stability against external faults and fast, reliable performance against internal faults. It consists of a current unit with 4 inputs.
It belongs to the S24 family, part of the SMARTLINE range. These devices offer a wide set of functions in a compact housing. Among other uses, they are particularly suited to the LV compartments of MV switchgear cubicles.
The particularity of these relays is that, although they belong to the SMARTLINE range, their hardware and firmware are the same as those of the relays making up the PROTECTA range. They therefore share the same physical and electrical characteristics. This provides extensive field experience of their use and operation, as well as consistent and optimum manufacturing lead times. The main difference between the two ranges is the housing.
The EuroCAP configuration tool, available free of charge, provides a user-friendly and flexible application for protection, control and measurement functions, ensuring that the protection devices are fully customisable.
General features
- Native IEC 61850, Edition 2 compatible
- Standard 144 × 144 mm housing
- The predefined factory configuration can be customised to the user’s specifications with the EuroCAP tool
- Various types of HMI:
- Colour touch screen
- Monochrome (B&W) alphanumeric display with 4 touch buttons.
- Built-in web server as well as extended measurement, control and monitoring functions.
- User-configurable LCD displays for the colour touch HMI, able to show single line diagrams with position indication and control of the switching devices, as well as measurement values of the controllable objects
- Adaptive protection
- Circuit breaker monitoring and control
- High-capacity disturbance recorder (DRE) and event logging:
- DRE supporting up to 32 analogue signal channels and 64 digital signal channels
- The event recorder can store more than 10,000 events
- Various mounting types:
- Flush-mounted;
- Semi-flush-mounted;
- DIN rail
- Wide range of communication protocols:
- Ethernet communication: IEC 61850; IEC 60870-5-104; DNP3.0 TCP; Modbus TCP
- Serial communication: DNP3.0; IEC 60870-5-101/103; MODBUS, SPA
- Legacy network protocols over 100Base-FX and 10/100Base-TX (RJ45)
- Optional communication ports:
- Ethernet over optical fibre (MM/ST, SM/FC),
- RJ45,
- POF serial,
- Serial over optical fibre,
- RS-485/422
- Simultaneous support of several communication protocols
- Built-in self-monitoring function (hardware and software) – Watchdog
- Various time sources available:
- NTP server;
- IRIG B
Applications
The S24/HZ relay is a high impedance digital relay. Its full set of functionalities allows it to be used on a busbar, a transformer, a generator or a motor for restricted earth fault detection. This operating principle requires stabilising resistors on each phase, and a non-linear resistor (Metrosil) is generally required across the relay circuit terminals.
The high impedance relay can be configured either for three-phase protection applications (87T, 87B) or for restricted earth fault protection applications (87N), according to the ordering option named “Number of differential currents“:
- By selecting a “CT+/5153” current input module, only the 4th current channel is assigned to high impedance differential protection, while the first 3 input channels of the unit are used for overcurrent protection.
- By selecting a “CT+/5116” current input module, its first three channels (three phases) are assigned to high impedance differential protection with phase segregation.
The built-in current transformer supervision function (CT50), with its sensitive differential element, detects an open circuit in the secondary wiring circuits of the current transformers.
Field of application
- High impedance differential protection for busbar, transformer, generator, reactor and motor applications
- Built-in current transformer supervision function
- Depending on the relay configuration:
- High impedance earth fault protection (87N) with conventional current-based protection functions such as 50, 51, 50N, 51N, 50BF
- Three-phase high impedance differential protection (87T, 87B)
Protection and control functions
Depending on the option chosen, the S24/HZ (V7) relay measures either the three phase currents and one differential current (87N), or only the differential currents of the three phases. The main functions are the high impedance differential function (single-phase or three-phase) and its counterpart, current transformer supervision.
Note that the additional functions (50, 50N, 51, 51N, 60, 68) are only available in the option with a single differential current (87N).
Click on the following link to download the general documentation : S24 General documentation
Click on the following link to download the operation manual : Please contact our Sales Department
Click on the following link to access the technical documentation to attach to your order : DOCACOM_S24
