Instructions Explained
VAr Volt-Ampere reactive power, relating to voltage control in the power system Dispatch See National Electricity Rules has the following instructions in a cycle.
Signal
A signal file communicates a new solution is pending and participants must cease outstanding actions. A signal file’s purpose is to terminate the previous instruction set and precede the next instruction set.
Instruction
Instruction files follow a signal file to communicate a new set of instructions for participant devices.
Supplemental
Supplemental instructions:
- Are optional and add to the current cycle’s instruction set, including any other supplemental instructions in the cycle.
- Share the same Run_DateTime as the originating instruction but have an incremented Version_DateTime.
- Can be issued by AEMO Australian Energy Market Operator between zero to five times within one VDS VAr Dispatch Scheduling; the system that produces instructions for reactive plant cycle.
- Can contain one or more additional instructions. They may also contain revocation of one or more previous instructions.
- Are further instructions submitted in addition to the current set of instructions to either, revoke or add an instruction.
- Do not replace the current cycle’s set of instructions, although they can supersede an individual instruction in the instruction set.
- Cannot edit the target value of a previous instruction in the cycle (for example, cannot change a previously requested delta tap or delta kV analog value).
- Only contain the additional and/or revoked instructions for the cycle. They do not contain the full instruction set previously issued.
- Content is cumulative; it does not replace the entire previous instruction file or supplemental files but adds to the instruction set.
- Remain valid for execution, along with the entire instruction set, until the end of that cycle, even if issued earlier in the cycle, except if AEMO issues a revocation.
- Can only follow instruction files or previous supplemental files; they cannot follow a signal file.
- Must be executed by RPOs, as per current instruction set functionality.
- For example, a scenario where AEMO issues a first instruction to switch a capacitor out of service, then after a few minutes, a second supplemental instruction to keep the capacitor in service and the RPO has already switched it out of service. What does the RPO do? They use their discretion whether to inform AEMO or wait for the next instruction.
- Are no longer valid when a new VDS cycle starts. A signal file is sent out and the previous instruction set, including any supplemental instructions become invalid.
- Are added by AEMO controllers manually.
