The American SEL-551C protection device overcurrent/reclosing relay

We offer remote or on-site installation and commissioning services for the American SEL-551C overcurrent/reclosing relay protection device! SEL-551C, full model 0551C0CX132X, is sourced directly from the manufacturer. We provide fast quotes and operation manuals and installation instructions.

Original SEL microprocessor protection device factory test reports and SEL relay driver CDs are included with every shipment. The SEL microprocessor protection device, also known as the SEL overload protection relay SEL-551C, functions as an overload current/reclosing relay. The full manufacturer is Schweitzer Engineering Laboratories (abbreviated SEL).

Our popular original American SEL microprocessor protection device product series includes: SE-451, SEL-751, SEL-751A, SEL-351, SEL-351A, SEL-351S, SEL-551, SEL-551A, and SEL-651RA. SEL-551C Microprocessor-based Protection Device Product Introduction: SEL-551C Relay Product Functions: Overload Current/Reclosing Relay.

The SEL-551C microprocessor-based protection device provides overload current relay users with new flexibility in distributed system protection. The SEL-551C offers six inputs and three products with two communication ports for more control options.

SELogic control equations add rising and falling edge triggers and latch-up logic for custom applications.

Measurement/Protection Current Value: Overload Current. Other Features: Digital, Configurable, Adjustable, Programmable. SEL-551C 0551C0CX132X Physical Image: The SEL-551C protection device overcurrent/reclosing relay is an integrated overcurrent reclosing protection and control device that combines protection, measurement, monitoring, and control functions.

We are an authorized distributor of original SEL microprocessor-based protection devices. The SEL-551 relay is a comprehensive overcurrent reclosing protection and control device integrating protection, measurement, monitoring, and control functions.

overcurrent, zero-sequence, differential, and heavy gas protection; it measures input current, zero-sequence ground current, and negative-sequence current, and reports and records events and sequence events.

It also features flexible control logic, allowing arbitrary setting of the relay's current and other collected equation quantities. Through OR, AND, and NOT logic, it controls the alarm, trip, and signal transmission of the circuit to the central control computer.

Reclosing and synchronization functions are primarily for power plants and are not used in our company.

To illustrate the relay's functions, a functional block diagram is shown in Figure

• Taking a feeder as an example, the SEL-551 relay takes the current signal from the feeder's current transformer and connects it to the relay. The relay performs comprehensive comparison and analysis of the signal and acts on the instantaneous overcurrent element
• , the inverse time current element
• , the reclosing element (79, unused) to perform protective action on the circuit breaker. As long as the action conditions are met, it can effectively trip the circuit breaker
• and perform timely monitoring of the line.
• and
• are all types of phase, zero sequence, negative sequence, and neutral point grounding faults, and can play a role in all possible faults. The relay can also issue event reports and sequence event record reports to help effectively and quickly analyze the fault type and take corresponding solutions. The operation introduction of the American SEL relay SEL-551C is as follows: The front panel of the SEL-551 relay includes 8 LEDs, 1 LCD display, and 8 operation buttons.
• LEDS indicator The meaning of the 8 LEDS indicator lights of the SEL relay is shown in Table
• When a new TRIP trip relay reaches the word position, the indicator lights numbered 2 to 6 are updated and maintained. The indicator lights can be reset by pressing the TARGET RESET/LAMP TEST button on the front panel or by sending the TAR R command through the serial port (TAR R - status reset).
• LCD display The relay setting value, input current, zero-sequence ground current, negative sequence current and other measured values can be seen on the LCD display;
• event log reports and relay setting operations can be performed.
• Operation buttons --- SEL relay SEL-551C operation introduction There are 8 buttons on the front panel of the SEL relay function. Through these 8 buttons, real-time data can be read, historical events can be viewed, protection settings can be displayed or modified and local control can be performed. Each button has a dual meaning and is called a primary function button and a secondary function button respectively. SEL-551C Relay Function Operation Introduction
• Setting Values: Relay settings can be viewed and set using the SHOW or SET serial port command and the SET button on the front panel. The SET button on the front panel can only view and set the RELAY, PORT, and PASS settings. Programmable timers, inputs, trip conditions, event report trigger conditions, and output can only be set using the SET command through the serial port on the rear panel. After the computer establishes communication with contacts the relay, the relay can be set through a terminal emulator, or the relay setting software can be used to download the settings to the computer, modify them offline, and then download them back to the relay. (SHOW—View, SET—Set, RELAY—Relay, PORT—Serial Port, PASS—Command) How to install and wire the American SEL-551C relay? This SEL relay is designed for the entire power system. In practical applications, the wiring method and function will depend on the specific situation. Based on the specific conditions of our company's 6.3kV system, some modifications have been made to the wiring diagram in the instruction manual to effectively utilize existing equipment, as shown in Figure
• Original SEL 0551C0CX132X from the US SEL manufacturer, genuine guaranteed quality, good discounts, and fast air freight customs clearance! The SEL relay is connected to terminals 101, 102, 103, 104, 105, and 106 of the SEL-551 relay via leads A411, B411, C411, and N411 of the original current transformer. The polarity input terminals of the current transformer are 101, 103, 105, and 107. The SEL relay operates at a rated power of 220VDV, connected to terminals 215 and 216. Note that the polarity markings are 215 (+) and 216 (-). The relay grounding terminal GND must be reliably grounded. The zero-sequence current transformer input IN signal is located at terminals 107 and 108. The circuit breaker status input is rated at 220VdV. When the rated control voltage is input, each opto-isolated input draws approximately 4mA of current, located at terminals IN1 (201-202) and IN2 (207-208). If the circuit breaker is in the closed position: the auxiliary contact of the circuit breaker connects IN1 (201-202) to inform the SEL-551 relay circuit breaker that it is closed; auxiliary contact of the circuit breaker connects IN2 (207-208) to inform the SEL-551 relay circuit breaker that it is open.

Share Article