Ask our team:
  • Phone: +86 181 0690 9650
  • E-Mail sales1@apterpower.com
  • Lifecycle status

    Discontinued / Obsolete by OEM
    Apter Power supports CT-data review, exact matching, and sourcing.

7UT5121-4CB01-0AA0/LL

/ 4.9
1001 reviews | Need a Specific Revision?
Siemens 7UT5121-4CB01-0AA0/LL is a 1 A SIPROTEC 3 differential protection relay for transformers and other protected zones operating at 16 2/3, 50 or 60 Hz.
In Stock
Ships by Wednesday, October 28
Fast Shipping Available
Get a quick price for 7UT5121-4CB01-0AA0/LL
Quantity
*E-mail
Company
*Mobile
*Content
Upload (gif, jpg, jpeg, png, bmp, doc, docx, xls, xlsx, ppt, pdf, csv)

Technical specifications for 7UT5121-4CB01-0AA0/LL

  • Manufacturer:
    Siemens
  • Part Number:
    7UT5121-4CB01-0AA0/LL
  • Product Family:
    Siemens SIPROTEC
  • Product Type:
    SIPROTEC 3 Differential Protection Relay
  • Stock:
    1
  • Rated current:
    1 A
  • Rated frequencies:
    16 2/3 Hz, 50 Hz, 60 Hz
  • Auxiliary supply:
    60/110/125 V DC
  • Protection principle:
    Current differential
  • Application scope:
    Transformer or protected electrical zone
  • Compensation:
    Configured CT ratio and vector-group compensation
  • Restraint:
    Setting-dependent differential stabilization
  • Event evidence:
    Fault and status records available for analysis
  • Weight:
    12.434 lbs (5.64 kg)
  • Estimated shipping dimensions:
    14.9 x 23.4 x 26.7 cm
  • Tariff Code:
    8537101190
  • Country of origin:
    Germany
  • Place of shipment:
    Xiamen,Fujian,China
By purchasing this item, you agree to the Terms & Conditions, ApterPower is not an authorized distributor for listed manufacturers or tradenames and therefore the manufacturer's warranty does not apply. All our products come with ApterPower's 1-year warranty.

More Information

Overview Manuals Applications Diagnostics & Protection Safety Standards

Features:

  • Performs numerical differential protection for a defined electrical zone.
  • Supports 16 2/3, 50 and 60 Hz applications.
  • Uses the 1 A measurement configuration with 60/110/125 V DC supply.
The /LL suffix completes the hardware and option identity of this 7UT51 relay.

Its operating security depends on matched current inputs and the configured restraint characteristic.

Transfer the original asset data and test the CT circuit before closing the case trip links.

Availability is confirmed against the complete 7UT5121-4CB01-0AA0/LL identity, required condition, quantity and delivery destination at quotation.
Verified resources for Siemens 7UT5121-4CB01-0AA0/LL: Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
  • Protect a power transformer through restrained current-differential measurement.
  • Supervise a generator-transformer or bus-connected differential zone.
  • Retain a commissioned SIPROTEC 3 scheme while planning a protection upgrade.
  • Differential and restraint quantities reveal CT or protected-zone abnormalities.
  • Event records identify element pickup and trip progression.
  • Binary-status checks help separate relay logic from external trip-circuit faults.
  • CT secondary circuits must never be left open during live primary service.
  • Trip links should remain isolated until commissioning tests are complete.
  • Use the site's protection-work permit and independent setting verification.
  • Protection testing should follow the utility or plant acceptance procedure.
  • Insulation and terminal practices must match the switchgear design.
  • Setting approval remains governed by the applicable coordination study.
Description
7UT5121-4CB01-0AA0/LL provides numerical differential protection within the SIPROTEC 3 generation. The label identifies a 1 A measuring circuit and operation at 16 2/3, 50 or 60 Hz with 60/110/125 V DC auxiliary power. This order configuration belongs to a protection scheme that measures the differential zone as a complete system, including every CT circuit and the wiring between the protected equipment and relay panel.

The relay compares the currents entering and leaving the protected zone and applies the configured restraint and tripping logic. Transformer vector-group compensation, CT ratios and zero-sequence treatment are defined by the protected asset and the approved settings. It is used on transformers or other important apparatus where fast internal-fault clearance must remain stable during through-fault current, inrush and normal load transfer.

Successful replacement depends on the exact case connections, CT polarity, phase assignment and stored parameter set. Never energize the trip path until bias characteristics, harmonic restraint and every connected binary circuit have been tested. The acceptance program should exercise differential pickup, restraint, harmonic blocking, trip contacts and event recording with the breaker or lockout path controlled by an approved test procedure.
Alternative Names
7UT5121-4CB01-0AA0/LL 7UT5121 4CB01 0AA0 LL 7UT51214CB010AA0LL Siemens 7UT5121 SIPROTEC 7UT51 Differential Relay 7UT51 Transformer Differential Protection Siemens Differential Relay 7UT5121-4CB01-0AA0/LL
Technical notes
CT polarity or ratio errors can create false differential current in 7UT5121-4CB01-0AA0/LL; verify the complete secondary circuit before enabling tripping.
Exceptional Service

Our Mission

  • 100% Satisfaction

    We believe expertise is priceless. With over 20 years of experience, and top engineers on staff, we can help you solve or avoid problems that threaten your business.
  • Trust Guaranteed

    Not only do we have a vast inventory, our team makes sure every piece of equipment is in working condition. Your purchases are also backed by our Warranty.
  • Expertise

    Time is money, especially when your equipment is down. We work quickly to get your equipment on its way so you can get it back up and running.

FAQS

The following is a list of questions commonly asked by our customers. Please contact us if you have a question about our process that is not answered below.
Which frequency systems can Siemens 7UT5121-4CB01-0AA0/LL protect?
The device marking covers 16 2/3 Hz as well as standard 50 Hz and 60 Hz systems.
Why are transformer vector-group data essential to Siemens 7UT5121-4CB01-0AA0/LL?
They determine the phase and magnitude compensation required for a stable differential comparison.
Where is Siemens 7UT5121-4CB01-0AA0/LL placed in a protection architecture?
It supervises the CT-defined zone for a transformer or another protected asset and trips the assigned breakers.
How is legacy availability established for Siemens 7UT5121-4CB01-0AA0/LL?
The quotation records the exact suffix, terminal case, device condition, quantity and achievable delivery time.
What must be reconciled if a newer relay replaces Siemens 7UT5121-4CB01-0AA0/LL?
CT inputs, compensation, restraint settings, binary logic, communications and panel terminals all require engineered conversion.
Which manual sections matter most for a 7UT5121-4CB01-0AA0/LL request?
Supply the connection diagrams, setting list, CT data and differential-test report together with the nameplate image.