American SEL-787 transformer protection relay
LEHIY item code: LH-SEL-0039
Quick buying check
This page helps you check American SEL-787 transformer protection relay before you ask for a quote.
Confirm the brand, model number, part number, and quantity. Share a clear nameplate photo when the old item has close variants.
LEHIY can check stock, lead time, packing, shipping documents, and safe replacement options for maintenance orders.
We offer remote or on-site installation and commissioning services for SEL products, including the American SEL-787 Transformer Protection Relay. We source directly from the American SEL manufacturer, guaranteeing authenticity, and utilize group-buying logistics for competitive pricing.
We recommend choosing the SEL-787-2/-3/-4 transformer protection relay instead of the SEL-787. The SEL-787-2/-3/-4 provides additional protection and communication options, such as protection for two-, three-, and four-winding transformers and EtherNet/IP. It also features a color touchscreen display.
SEL will continue to support and provide warranty for the SEL-787.
The main features of the American SEL-787 transformer protection relay are as follows: Complete dual-winding protection – employs dual-winding, dual-slope differential protection with phase, negative sequence, zero sequence, and neutral overcurrent elements as backup protection. Circuit breaker failure protection for two 3-pole circuit breakers.
Additionally, the SEL-787 can be used to protect three-phase autotransformers. Cost-Saving Transformer Monitoring—Extend transformer life by monitoring ambient temperature, on-load tap changer (LTC) tank temperature, and transformer oil temperature using optional 4–20 mA analog inputs or resistance temperature detector (RTD) thermal inputs.
Monitor shoot-through failure counts, cumulative I²t, and failure duration to determine the frequency and impact of external faults on the transformer, preventing catastrophic failures. Fan Group Control—In addition to RTD thermal elements, fan group control and protection are available via optional single-phase CT channels.
Beyond Basic Transformer Protection—Comprehensive transformer protection is achieved through optional single-phase sensitive REF inputs and three-phase input voltages. Eliminate the need for separately installed metering devices using built-in metering functions, including harmonics, power, phase voltage and current, neutral current, and sequential voltage and current.
Reliable Protection in Harsh Environments—The SEL-787 operates under harsh conditions, with a temperature range of –40°C to +85°C (–40°F to +185°F), and is designed and tested beyond applicable standards, including vibration, electromagnetic compatibility, and adverse environmental conditions.
Furthermore, the SEL-787 has passed ATEX and Underwriters Laboratories (UL) Class I 2 certifications, making it suitable for use in hazardous and potentially explosive environments. Our company offers a superior supply of the American SEL-787 transformer protection relay, sourced directly from the manufacturer to ensure authenticity.
The SEL-787 microprocessor-based protection device also features the following functions: Dual-winding differential current protection, overcurrent protection, and circuit breaker failure protection. It employs dual-winding dual-slope differential protection with phase, negative sequence, zero sequence, and neutral overcurrent elements as backup protection.
Circuit breaker failure protection is provided for two 3-pole circuit breakers. Safety and reliability are ensured, providing maximum safety under external faults and transformer inrush current conditions. Under energized or normal operating conditions, it uses combined harmonic blocking and suppression differential elements for rapid detection of internal faults.
For more details on the American SEL-787 transformer protection relay, please contact our sales department.
Plain language sourcing guide for American SEL-787 transformer protection relay
Start with the full model name. Check the brand name. Check the part number. Check the code on the old unit. These small checks help you avoid a wrong order.
Take one clear photo of the front label. Take one photo of the side label. If the part has a cable, plug, port, seal, coil, or screen, take a photo of that area too.
Tell us the quantity you need. Tell us your country. Tell us the date when the plant needs the part. We can then check stock, lead time, safe packing, and the best shipping plan.
If the exact model is no longer made, do not guess. Send the old model and the use case. LEHIY can compare close options and explain which choice is safer for repair work.
Use simple order notes. Write the model in one line. Write the quantity in one line. Write the delivery country in one line. This helps our team reply faster.
Check the old part before removal. Look at the label. Look at the connector. Look at the mounting size. Look at the voltage or pressure rating if it is shown.
Do not rely on a short nickname for a part. Many industrial items have close versions. A small suffix can change the plug, output, range, or software setting.
Ask for a stock check if the plant is stopped. Ask for a lead time if the order is planned. Ask for packing photos if the part is fragile or heavy.
For a replacement order, tell us what failed. Tell us where the part is used. Tell us if an equal model is acceptable. This makes the first answer more useful.
For repeat orders, send the last invoice, old label, or old packing photo. The same reference can help us match the correct product again.
For urgent service, keep the message simple. One model, one quantity, one photo, and one delivery target are enough for a fast first check.
Share Article
| Brand Name: | SEL | Certification: | ISO9001, CE |
|---|---|---|---|
| Place of Origin: | China | Condition: | New |
| Warranty: | 1 year | Customized sourcing: | available |
What are your strengths?
Ans. LEHIY specializes in industrial automation and control components, offering fast sourcing, stable quality, and competitive prices for global customers.
What is your estimated delivery time?
Ans. Most items ship within 3-7 days. Customized or rare models may take 10-30 working days.
What are your primary product offerings?
Ans. Our main products include PLCs, sensors, valves, solenoid valves, actuators, power modules, transmitters, and complete industrial automation solutions.
How can I get in touch with you?
Ans. You can reach us anytime via Email, WhatsApp, LinkedIn, or our contact page. Our sales engineers respond quickly and provide technical support when needed.
What are your payment terms?
Ans. Standard terms are 50% TT in advance and 50% balance before delivery. We also support Alibaba Trade Assurance and L/C for qualified orders.
Feel free to Ask questions
Replacement support
American SEL-787 transformer protection relay
Send the brand, model, part number, quantity, nameplate photos, and application requirements. LEHIY will check availability, suitable alternatives, packing details, and delivery options before quoting.
For discontinued, temporarily unavailable, or configuration-sensitive items, our team can compare the requested model with close variants or compatible replacements for maintenance and spare parts planning.
Use this page as a practical sourcing note for engineers, buyers, and maintenance teams comparing automation components. Check the model name, brand, LEHIY code, application, and replacement requirements before sending an inquiry.
Short, clear information helps our team confirm availability faster and reduce back-and-forth communication during urgent maintenance projects.
- Confirm the complete model number and any suffix printed on the nameplate.
- Share quantity, destination country, preferred shipping method, and target delivery date.
- Include photos, drawings, old purchase records, or datasheets when compatible alternatives are acceptable.
- Ask for stock checking, replacement comparison, packing details, and export documentation before ordering.
Useful details for a faster quote
- Complete model and part number
- Required quantity and target delivery date
- Nameplate photos, drawings, or old purchase records
- Voltage, signal range, dimensions, or accessory needs
Model matching
We review brand, model, part number, nameplate photos, installation environment, and replacement requirements.
Quality and delivery
Each order can be checked for authenticity, condition, packing, warranty, shipping method, and delivery schedule.
Stock alternatives
For urgent maintenance projects, we can help check stock, compatible alternatives, and fast international shipment.
American SEL-787 transformer protection relay verification notes
Please send the full model number, quantity, target delivery date, and nameplate photos. These details help us check the requested product or a close replacement.
LEHIY reviews product name, part number, series, label information, and application requirements before shipment.
If the original model is discontinued or supplied with different accessories, we can explain practical differences before quoting.
For repeat purchasing, we can help organize related models, replacement parts, shipment schedules, and clear communication for your team.
Related Products
Helpful links
Explore More
Product family
More In This Category
Trusted partners
We have collaborated with many well-known enterprises, contributing to their success and establishing a strong reputation as a trusted partner in the industry.
