ABB REX521GHHPSH51G

Description

Detailed parameter table

ABB REX521GHHPSH51G

Product introduction

The REX521GHHPSH51G is an advanced and highly versatile feeder protection relay from ABB, engineered with precision to meet the complex demands of modern power distribution systems. As part of ABB’s renowned product portfolio, this relay is designed to offer reliable protection, efficient control, accurate measurement, and comprehensive supervision within medium – voltage networks. It also plays a crucial role in safeguarding large or medium – sized three – phase AC motors in circuit – breaker – controlled motor drive systems.

In medium – voltage distribution substations, the REX521GHHPSH51G serves as a cornerstone for protecting incoming and outgoing feeders. By continuously monitoring electrical parameters such as current, voltage, and frequency, it can quickly detect any deviations from normal operating conditions. In the case of an incoming feeder, it ensures that the power supply from the grid is stable and free from faults. If an overcurrent or earth – fault occurs in the upstream grid, the relay’s overcurrent and earth – fault protection mechanisms will be activated, rapidly tripping the circuit breaker to prevent damage to the substation equipment.

For outgoing feeders supplying power to industrial or commercial customers, the REX521GHHPSH51G provides essential protection against faults within the customer’s premises. In the event of a short – circuit in a factory’s electrical system, the relay’s advanced protection functions can detect the fault within milliseconds and isolate the affected feeder. This not only minimizes the impact on other customers but also helps to prevent widespread power outages in the area.

The relay’s ability to interface with both conventional current and voltage transformers, as well as having a version compatible with current and voltage sensors, offers great flexibility in system integration. This means that it can be easily incorporated into existing power distribution setups, whether they are using traditional or more modern sensor – based technologies.

Core advantages and technical highlights

Comprehensive protection functions

The multi – stage overcurrent protection, both in terms of 3 – phase non – directional overcurrent and non – directional earth – fault protection, sets the REX521GHHPSH51G apart from many other relays. The 3 – stage approach allows for a more nuanced response to different levels of current abnormalities. For example, the first stage can be set to detect minor overcurrents and issue an early warning, while the second and third stages can be configured to trip the circuit breaker at progressively higher current levels, depending on the severity of the fault.

The phase discontinuity protection is a vital feature, especially in applications where the proper functioning of three – phase equipment is critical. In a manufacturing plant running complex machinery, a phase discontinuity can cause motors to run unevenly, leading to premature wear and tear or even complete failure. The REX521GHHPSH51G can quickly identify such issues and take appropriate action, such as shutting down the affected equipment to prevent further damage.

The 3 – phase thermal protection, by continuously monitoring the thermal stress on the system, acts as a preventive measure against overheating. In a data center with a high – density of servers, the power consumption can cause significant heat generation in the power distribution system. The thermal protection in the REX521GHHPSH51G can detect the early signs of overheating and trigger actions like increasing ventilation or reducing the load, thereby ensuring the continuous operation of the data center.

The ability to detect transformer inrush and motor start – up currents is a key advantage. When a large transformer is energized or a high – power motor starts up, the inrush currents can be several times higher than the normal operating current. Less – advanced relays may misinterpret these normal transient currents as faults and trip the circuit breaker, causing unnecessary disruptions. The REX521GHHPSH51G, however, can accurately distinguish between these transient events and actual faults, allowing for smooth operation during these critical moments.

Efficient communication capabilities

With support for multiple communication protocols like SPA, IEC, Modbus, and Lon, the REX521GHHPSH51G enables seamless integration into a wide range of control and monitoring systems. In a smart grid environment, where real – time data exchange is crucial for efficient grid management, the relay can communicate with the central control station via Modbus. It can transmit information such as the current load on the feeder, the occurrence of any faults, and the power quality parameters. This real – time data allows grid operators to make informed decisions, such as redistributing load or scheduling maintenance, in a timely manner.

The communication capabilities also facilitate remote control of the relay. Operators can remotely adjust the protection settings, perform diagnostic tests, or even trip the circuit breaker in case of an emergency. In a large – scale power distribution network spread over a wide geographical area, this remote control functionality can save significant time and resources compared to sending technicians to the physical location of the relay.

User – friendly interface

The 6 x 16 character display on the REX521GHHPSH51G simplifies local operation and monitoring. Technicians can easily access important information such as the real – time current and voltage values, the status of the protection functions, and any fault indications. The display is designed to be intuitive, with clear and concise readings. For example, in a substation where quick assessment of the feeder’s condition is necessary during maintenance or in the event of a fault, the technician can quickly glance at the display and understand the situation without having to rely on complex software interfaces or additional monitoring devices.

The display also allows for easy navigation through the relay’s settings. Technicians can adjust the protection thresholds, configure the communication parameters, or view the historical data logs directly from the display. This user – friendly interface reduces the learning curve for operators and enables faster troubleshooting, ultimately leading to reduced downtime in the power distribution system.

Self – supervision and high reliability

Equipped with autodiagnostic circuits, the REX521GHHPSH51G constantly monitors its own performance. These circuits check for any internal malfunctions, such as component failures, communication errors, or incorrect calibration. In the event of an issue, the relay can take immediate action, such as issuing an alarm, isolating the affected part of the system, or switching to a redundant mode (if available). This self – supervision feature ensures high reliability, as it can detect and address potential problems before they lead to false operations or system failures.

In applications where continuous and accurate operation is essential, such as in utility substations or industrial plants with critical processes, the self – supervision of the REX521GHHPSH51G provides an added layer of confidence. The relay can operate with minimal human intervention, as it is constantly self – checking and maintaining its optimal performance.

ABB REX521GHHPSH51G

Typical application scenarios

Medium – voltage distribution substation

In a medium – voltage distribution substation, the REX521GHHPSH51G is a vital component for protecting incoming and outgoing feeders. As an incoming feeder protection device, it monitors the power supply from the grid. If there is a sudden increase in current due to a fault in the upstream grid, such as a short – circuit in a transmission line, the relay’s overcurrent protection will quickly detect the abnormal current. The multi – stage overcurrent protection will first assess the severity of the fault. If it is a minor overcurrent, it may send an alarm to the control room. However, if the current exceeds a critical threshold, the relay will trip the circuit breaker within milliseconds, preventing the high – current fault from reaching the substation equipment and causing damage.

For outgoing feeders, the relay provides protection against faults within the customer’s premises. Consider a substation supplying power to a commercial area with multiple shops and offices. If a short – circuit occurs in one of the buildings due to a faulty electrical appliance or a wiring issue, the REX521GHHPSH51G will detect the sudden change in current and voltage. The earth – fault protection will quickly identify if the fault is an earth – related issue, and the overcurrent protection will determine the magnitude of the fault. Once the fault is detected, the relay will isolate the affected feeder, ensuring that the power supply to other customers in the area remains uninterrupted.

Industrial plant with three – phase AC motors

In an industrial plant with numerous three – phase AC motors, the REX521GHHPSH51G is deployed to protect motor feeders. During motor start – up, the high inrush current can be a challenge for the power system. The relay’s ability to detect inrush currents accurately ensures that the motor is not mis – tripped due to these normal starting currents. For example, in a large – scale manufacturing plant with heavy – duty motors used in production lines, when a motor starts up, the REX521GHHPSH51G will recognize the inrush current as a normal transient event. Once the motor reaches its normal operating speed, the 3 – phase thermal protection takes over.

The 3 – phase thermal protection monitors the motor’s temperature. If the motor starts to overheat due to mechanical issues such as a jammed bearing or excessive load, the relay will detect the increase in temperature – related stress on the system. It can then take appropriate action, such as sending an alarm to the plant’s maintenance team or, in severe cases, tripping the motor to prevent damage. This protection is crucial for maintaining the continuous operation of the industrial plant, as motor failures can lead to significant production losses.

Related model recommendations

ABB RED521 1MRK002003 – BA

This is a more advanced numerical line protection relay. While the REX521GHHPSH51G focuses on feeder and motor protection in medium – voltage networks, the RED521 is designed for high – voltage transmission and distribution lines. The RED521 offers features like distance protection, which is more suitable for long – distance line protection. For example, in a large – scale power grid with long – distance transmission lines connecting different regions, the RED521 can accurately locate faults along the line using its distance protection capabilities. However, in some complex power systems, they can complement each other. The REX521GHHPSH51G can handle the lower – level feeder protection within a substation or an industrial area, while the RED521 protects the main transmission lines, ensuring a comprehensive protection scheme for the entire power system.

ABB REL551 1MRK002480 – AE

A cost – effective overcurrent relay, the REL551 can be used in secondary protection roles in systems where the REX521GHHPSH51G is the primary feeder