UVR-1 LTC Universal Load Tap Changer Control

For retrofitting onto existing Load Tap Changing Transformers or supplied with new LTC Transformers

Features

The UVR-1 LTC advanced technology control can be retrofitted onto most three-phase power transformers with load tap changers. With a Mil Spec design platform that shares a common bond with the UVR-1 control for single phase line voltage regulators, the UVR-1 LTC control has upgraded surge protection as well as special software for complex tap changer operation. It uses solid-state relays for enhanced reliability and extensive use is made of stainless steel for the panel and housing as well as in adaptor brackets to meet various mounting configurations. The UVR-1 LTC is an attractive solution when upgrading controls on LTC transformers.

The UVR-1 LTC is driven by a 32-bit Motorola processor, an expandable CPU, and has programmable software that can be upgraded in the field.

The UVR-1 LTC has a non-volatile flash memory to store control data and configuration settings in order to eliminate the need for a battery.

The UVR-1 LTC has an optional 8-port programmable input/output - AC or DC optically isolated relay modules - that controls or monitors eight additional LTC or substation functions via the DNP-3.0 communication menu of the UVR-1 LTC.

The DNP-3.0 Level 2 provides over 500 analog and binary data points of Class – 0,1,2,3 and selectable communications modes including RS-232, IEEE-485, Fiber Optics, and Ethernet. The UVR-1 LTC capability for DNP-3.0 Level 2 report by exception was given world-wide certification by ACS (Atlanta, GA) on March 25, 2002 to the new 2001 code library.

An optional 12-24-48-120V DC battery backup is available for the control’s CPU board. If there is a power loss, it provides continuous looped communications on all ports. This is a major benefit when stringing communications serially throughout substation devices to limit inputs to RTU communication devices.

The UVR-1 LTC has been tested and certified by the American Electric Power Dolan Test Laboratory in Columbus, OH as meeting the following ANSI/IEEE standards:

Radio Frequency (RF) Immunity ANSI-IEEE 37.90.2 (1987)
Electro-Static (ESD) Immunity IEC-61000-4-2 (1995-2001)
Oscillatory-Surge Withstand (SWC) Immunity ANSI-IEEE 37.90 (2002)
Fast Transient- Surge Withstand (SWC) Immunity ANSI-IEEE 37.90.1 (2002)

Advantages

Most older and many newer LTC controllers do not have remote communications capabilities, they do not provide data logging nor power measurement information of the electrical system, and they require additional devices to meet customer needs. ICMI has overcome these shortcomings with its UVR-1 LTC control. By upgrading the controls on existing LTC Transformers with the UVR-1 LTC - including those with multiple neutrals - utilities can realize the benefits of current technology. And as an option ICMI can provide a field service engineer experienced in the installation of the UVR-1 LTC for start up assistance.

Tap position monitor -The UVR-1 LTC advanced design provides no-loss tap position indication, even following a loss of power. The non-volatile data storage means there will be no loss of critical data, which includes tap position recall. On a competitive control, an INCON shaft encoder is generally specified in order to ensure that tap position is not lost.

“First House” protection - Redundancy is not needed since the basic design of the UVR-1 LTC includes a configurable “Voltage Limiting” setting providing both upper and lower set points as well as auto run-back.

“Over Current Protection” (Beckwith M-0170A AC Current Relay) - Over current protection is designed into the UVR-1 LTC. Sensing is via a 0.2A current transformer (0.440amp maximum) and ICMI can supply an auxiliary 5.0:0.2 amp current reduction transformer when required.

LTC Back-up relay (Beckwith M-0329B LTC Backup Control) - This relay is not necessary with the proven reliability of the UVR-1 LTC.

Paralleling (Beckwith M-0115A Beckwith Parallel Balancing Module plus Beckwith M-0127M AC Current Relay) - The ICMI approach is to use a “Master/Slave” arrangement using optional XIO boards which is more stable and it negates the need for additional auxiliary CTs while minimizing the level of circulating currents.

On the Top of this page is an example of how the UVR-1 LTC replaces the multiple relays that were previously required. On the next picture is a new installation using the UVR-1 LTC.

The Master/Slave parallel operation of multiple LTC transformers is accomplished via the use of 8-port XIO auxiliary boards. The assigned “Master” will perform the control monitoring and send corresponding raise or lower commands to “Slave” LTC controllers which have been auto-inhibited from doing their own raise/lower and instead receive their commands from the “Master” LTC controller. This keeps all the tap positions synchronized. Each of the individual “Slave” controllers will still create and retain their own log of power measurement values.

The UVR-1 LTC carries a limited 10-year warranty - “If you build them better, you back them better.”