substation breaker interlock (graphical LD)¶


suite id	`g_substation_breaker`
domain	power_substation
language	LD-graphical
difficulty	medium
validation status	validated
origin	authored
license	CC-BY-4.0

Authored for this suite to cover this domain with genuine control logic

What is proved¶

From benchmarks/power_substation/g_substation_breaker/props.yaml. What each kind claims, and what it becomes on either route, is on The properties we prove.

id	kind	claim	requirement
`P1`	`invariant`	`!(breaker_closed && fault)`	The breaker must never be closed into an active fault (protection interlock).

Variants¶

file	expected verdict	violates	method
`clean.xml`	SAFE	none	expert
`bomb.xml`	VIOLATION	`P1`	fault-injection

Files¶

file	what it is	size	sha256
`benchmark.yml`	benchmark metadata	1.0 KB	`ecd8a8f24c81`
`bomb.xml`	ladder program, PLCopen XML	3.2 KB	`e441d2245587`
`clean.xml`	ladder program, PLCopen XML	2.7 KB	`e09eea087647`
`props.yaml`	property file	0.2 KB	`e5653f52327a`

Structured text, derived¶

Read off the ladder graph by runner/ld_to_st.py: every rung's contacts and coils rewritten as IEC 61131-3 assignments, in the same series/parallel logic the PLCopen XML encodes. This is a reading aid, not a second source of expected verdicts; ESBMC verifies the ladder program shown above, never this rendering.

bomb.xmlclean.xml

PROGRAM g_substation_breaker_bomb
VAR_INPUT
    close_cmd : BOOL;
    fault : BOOL;
    lockout : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    breaker_closed : BOOL;
    alarm : BOOL;
END_VAR


breaker_closed := (((NOT fault OR (fault AND maint)) AND close_cmd) AND NOT lockout);
alarm := fault;

END_PROGRAM

PROGRAM g_substation_breaker_clean
VAR_INPUT
    close_cmd : BOOL;
    fault : BOOL;
    lockout : BOOL;
    maint : BOOL;
END_VAR

VAR_OUTPUT
    breaker_closed : BOOL;
    alarm : BOOL;
END_VAR


breaker_closed := ((NOT fault AND close_cmd) AND NOT lockout);
alarm := fault;

END_PROGRAM

Recorded runs¶

A task can carry two routes. ld is ESBMC's ladder front end reading the program directly. via C is the same solver reached through Beremiz and MatIEC, which is the only route that reaches ST, IL, FBD and SFC; see How ESBMC-PLC works.

g_substation_breaker__bomb (props.yaml, expected VIOLATION): v8.4 VIOLATION
g_substation_breaker__bomb__viac via C (props.yaml, expected VIOLATION): master VIOLATION
g_substation_breaker__clean (props.yaml, expected SAFE): v8.4 SAFE
g_substation_breaker__clean__viac via C (props.yaml, expected SAFE): master SAFE