2017   Add a pattern check in the XSD, using the set of characters allowed in an XPath expression, for the

Created: 09 Jan 2026

Status: Triage

Part: Part 90-30 (2025)

Links:

Page: 68

Clause: 9.3.3 ProcessResource

Paragraph: Table 25 – Attributes of the ProcessResource eleme

Issue

In table 25, the description of "selector" attribute states:
"The selector indicates searching rules to use during instantiation of a process resource to identify elements which may be used as reference. This selector is defined by an XPath which is a query language for XML. This allows indication of rules to search for specific elements in the SCL (e.g., searching a Bay with a specific name). XPath is a standard defined by W3C consortium freely available at https://www.w3.org/TR/xpath-3/."

However, in the XSD of IEC 61850-6-100, the datatype of the selector attribute is declared as "xs:normalizedString"

Proposal

A pattern should be added in the XSD, to restrict the allowed characters to those that are valid in an XPath expression.

For example :

//Function[@type=‘Protection’]//LNode[class=‘PTRC’]

is not a valid XPath expression, because the caracter ’ is not allowed in XPATH, while it is still accepted by the XSD type "xs:normalizedString"

A pattern check in the XSD would ensure that only allowed characters appear in the selector attribute and prevent invalid XPath expressions from being declared.