ABB SPAD 346 C Stabilized Differential Relay

product overview

The ABB SPAD 346 C Stable Differential Relay is a device that plays a critical role in power system protection and other aspects. It is designed specifically to ensure the safe and stable operation of electrical equipment, and through advanced technology and reliable performance, it accurately performs protection tasks in various complex power environments. It is an indispensable and important component in power systems and industrial fields.

Specification parameters

Rated voltage: It usually supports multiple common rated voltage levels, such as 220V, 110V, etc., and can be flexibly selected according to actual application scenarios and power system requirements to ensure compatibility with power systems of different voltage levels.

Rated current: able to adapt to different current ranges, common rated current specifications include 5A and 1A, meeting the current monitoring and protection needs of various electrical equipment under normal operation and fault conditions.

Measurement accuracy: The measurement accuracy of electrical quantities such as current and voltage is extremely high, with a current measurement accuracy of ± 0.2% and a voltage measurement accuracy of ± 0.5%, ensuring the accuracy of equipment operation status monitoring data and providing reliable basis for timely detection of potential problems.

Action time: When a fault is detected and it is determined that a protective action needs to be taken, it can respond quickly with a very short action time, usually between a few milliseconds to tens of milliseconds. For severe faults, the action time can be as low as 5ms, effectively reducing the damage caused by the fault to the equipment.

Control input and output relay module

The control input and output relay module of the differential relay SPAD 346 C is fitted to the

rear panel of the relay in the same direction as the mother board.

To remove the module, the fixing screws have to be undone and the protec tive earth cable of the module plus  the flat cable connecting the mother board to the module have to be disconnected.

The control input and output relay module contains the output relays (8 pcs + IRF), the control circuits of the relays, the electronic circuits of the external control inputs (5 pcs) and the D connector required for serial communica tion.

A flat cable links the output and input signals of the module to the mother board.

The relay module locations U1, U2 and U3 are identical.

The output signals SS1…SS4 and TS1…TS4 of  the mother board control an output relay with

the same designation.

The operation of the protection stages of the relay module is not fixed to any specific output relays, but the stages can be linked to the desired output signals.

In con trast, the output relays TS1, TS2, TS3 and TS4 are the only output relays capable of circuit

breaker control (see “Circuit-breaker control”).

The configuration of the output relay matrix switchgroups of the relay modules is described

in the manuals of the relay modules.

Five external inputs BS1, BS2, BS3, BS4 and BS5 are available to the differential relay SPAD

346 C.

For example, the alarm and trip signals from the power transformer gas relay and the

winding temperature sensor can be linked to the external control inputs.

The external control inputs can be used for:- blocking one or several protection stages of the

relay modules- direct output relay control- the indication of the primary protection relay signals or operations- resetting the operation indicators, latched output relays, registers and recording memory- changing the actual setting values of the relay modules. i.e.switching from main setting val

ues to second setting values and vice versa.

The switchgroups of the relay modules are used to specify the influence of the external control

inputs BS1…BS5 on the operation of the relay and the active state of the control inputs.

The activation of a protection stage, a blocking function and an external control input is indi

cated on the display of the relay module by the red code representing the event.

The codes are explained in the manuals of the relay modules.

Event information is also received over the serial bus, when a protection stage, a blocking func

tion, an external control input or an output signal is activated.

Functional characteristics

Differential protection function: The core function of SPAD 346 C is differential protection. It can accurately compare the magnitude and phase of the current at both ends of the protected device. Once the difference in current between the two ends exceeds the predetermined threshold value, the protection action will be quickly triggered to cut off the circuit in a timely manner, effectively preventing equipment from being damaged due to internal fault currents and ensuring the safe and stable operation of the power system. For example, in important equipment such as generators and transformers, this differential protection function can quickly identify internal faults such as winding short circuits, avoiding the expansion of the fault range.

Excellent stability performance: With high stability, it can effectively resist common interference factors in the power system, such as unbalanced current caused by external short-circuit faults, current transformer saturation, etc. Through advanced algorithms and designs, faults can still be accurately diagnosed in complex power environments, reducing the possibility of misoperation and ensuring the reliability of protection functions.

Measurement and monitoring function: In addition to protection function, it can also accurately measure electrical quantities such as current and voltage. Real time monitoring of the operating parameters of the power system, and transmission of data to the monitoring system through communication interfaces, facilitates operation and maintenance personnel to understand the system’s operating status at any time, discover potential problems in a timely manner, and take measures.

Application scenarios

Power plant: Used for the protection of equipment such as generators and plant transformers in power plants. As the core equipment of power plants, the safe operation of generators is crucial. The SPAD 346 C can detect faults in the internal windings of the generator in a timely manner, such as phase to phase short circuits, turn to turn short circuits, etc., to protect the generator from damage and ensure the normal power generation and output of the power plant.

Substation: Suitable for differential protection of main transformers, distribution transformers and other equipment in substations. Substation is an important link in voltage conversion and energy distribution in the power system, and the reliable operation of transformers directly affects the stability of the entire substation. This relay can quickly respond to internal faults in transformers, ensuring the safe operation of substations and avoiding large-scale power outages caused by transformer failures.

Industrial enterprises: Used in the power supply system of large industrial enterprises, such as steel plants, chemical plants, etc., for the protection of important electrical equipment. The production process of these enterprises relies heavily on electricity support, and the failure of key equipment may lead to production interruption, causing huge economic losses. SPAD 346 C can effectively protect high-voltage motors, large rectifier equipment, etc. in industrial enterprises, ensuring the continuity and stability of industrial production.

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