# Station UTC-local display boundary

Canonical URL: https://eloragrid.ai/symbols/station-utc-local-display-boundary
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: SUDB
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: substations
Input: Recorded UTC time
Output: Local display time

Separates the common recorded time basis from an operator's displayed local time.

## In plain English

### What this block does

Separates the common recorded time basis from an operator's displayed local time.

### A simple example

In a substation, a station clock can provide precision timing to process equipment and another timing interface to event recorders. The alarm system should distinguish loss of a distribution path from loss of the external time source. For this reference, the drawing identifies “Recorded UTC time” at the input and “Local display time” at the output. Daylight-saving display changes must not alter event identity.

### What the drawings help you do

Start at the named input: Recorded UTC time. Identify its source device or document and the state represented on the drawing. Follow the named output: Local display time. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Recorded UTC time
- Output: Local display time
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Recorded UTC time → SUDB → Local display time
A reading guide. The entry's original illustration and input/output facts describe this application.

- [SEL-2488 satellite-synchronised network clock](https://selinc.com/products/2488/)


## What it represents

Separates the common recorded time basis from an operator's displayed local time. A station time system provides a shared time reference for protection records, measurements and automation. Different devices can use different timing protocols, so the time source, distribution path and quality information must remain identifiable.
In a substation, a station clock can provide precision timing to process equipment and another timing interface to event recorders. The alarm system should distinguish loss of a distribution path from loss of the external time source. For this reference, the drawing identifies “Recorded UTC time” at the input and “Local display time” at the output. Daylight-saving display changes must not alter event identity.
Show the source and client of each time connection. Required accuracy, holdover, protocol profile and loss-of-time behavior follow the selected application; a common timestamp format does not guarantee synchronized events. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation.

## How to read it

- Start at the named input: Recorded UTC time. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Local display time. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Daylight-saving display changes must not alter event identity.
- Show the source and client of each time connection. Required accuracy, holdover, protocol profile and loss-of-time behavior follow the selected application; a common timestamp format does not guarantee synchronized events.

## Information to show or reference

- Label the source and connection reference for recorded utc time.
- Identify the destination and defined state of local display time.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Daylight-saving display changes must not alter event identity.

## Important distinction

Daylight-saving display changes must not alter event identity. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

## Facts

- Representation: Functional block
- Installation focus: Substations
- Input / boundary: Recorded UTC time
- Output / connection: Local display time
- Lookup label: SUDB is a library lookup label, not a standard device designation.

## Public references

- [SEL-2488 satellite-synchronised network clock](https://selinc.com/products/2488/) — SEL. Public technical context for substation timing and event interfaces. PTP, NTP, IRIG-B, pulse distribution, reference failover and timing quality. The application text and educational graphic are independently authored; the publisher does not certify this representation.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.