# Surge-arrester disconnector indication interface

Canonical URL: https://eloragrid.ai/symbols/surge-arrester-disconnector-indication-interface
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: SDII
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchyards
Input: Arrester disconnector condition
Output: Disconnection indication

Identifies the selected arrester disconnection device or its documented status output.

## In plain English

### What this block does

Identifies the selected arrester disconnection device or its documented status output.

### A simple example

In a switchyard equipment diagram, the primary reference identifies the electrical role of an installed component while the linked equipment schedule and manufacturer drawing supply its exact construction and dimensions. For this reference, the drawing identifies “Arrester disconnector condition” at the input and “Disconnection indication” at the output. Not every station arrester has this accessory.

### What the drawings help you do

Start at the named input: Arrester disconnector condition. Identify its source device or document and the state represented on the drawing. Follow the named output: Disconnection indication. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Arrester disconnector condition
- Output: Disconnection indication
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Arrester disconnector condition → SDII → Disconnection indication
A reading guide. The entry's original illustration and input/output facts describe this application.

- [Gas-insulated switchgear](https://www.hitachienergy.com/products-and-solutions/high-voltage-switchgear-and-breakers/gas-insulated-switchgear)


## What it represents

Identifies the selected arrester disconnection device or its documented status output. High-voltage primary equipment carries, interrupts, measures or conditions the main power circuit. Its function, insulation arrangement and equipment boundaries need to be distinguished from the secondary signals used to control it.
In a switchyard equipment diagram, the primary reference identifies the electrical role of an installed component while the linked equipment schedule and manufacturer drawing supply its exact construction and dimensions. For this reference, the drawing identifies “Arrester disconnector condition” at the input and “Disconnection indication” at the output. Not every station arrester has this accessory.
Read the connected power path before interpreting a secondary output or alarm. These original educational component references provide no product dimensions, dielectric rating, installation clearance or construction approval. 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: Arrester disconnector condition. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Disconnection indication. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Not every station arrester has this accessory.
- Read the connected power path before interpreting a secondary output or alarm. These original educational component references provide no product dimensions, dielectric rating, installation clearance or construction approval.

## Information to show or reference

- Label the source and connection reference for arrester disconnector condition.
- Identify the destination and defined state of disconnection indication.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Not every station arrester has this accessory.

## Important distinction

Not every station arrester has this accessory. 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: Switchyards
- Input / boundary: Arrester disconnector condition
- Output / connection: Disconnection indication
- Lookup label: SDII is a library lookup label, not a standard device designation.

## Public references

- [Gas-insulated switchgear](https://www.hitachienergy.com/products-and-solutions/high-voltage-switchgear-and-breakers/gas-insulated-switchgear) — Hitachi Energy. Public technical context for high-voltage primary equipment references. Primary switching equipment and instrument-transformer interfaces. 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.