On 27 October 2018, voltage limits in Queensland changed to 230 volts (+10% and -6%), AS60038 “Standard voltages” specifies this range (216.2 to 253.0 volts). Similar changes happened in other states & territories.
From 1 July 2020, Australian electricity networks established a ‘preferred operating range’ of 230 volts (+6% and -2%) which equates to 225.4 to 243.8 volts and is set out in AS 61000.3.100 “Steady state voltage limits in public electricity systems”.
Previously the voltage limits had been 240 volts +/-6% (ie 225.6 to 254.4 volts)
Nobody can easily see the manually set parameters in old transformers in the national grid - until someone downstream of the transformer installs solar PV and then it becomes visible to the solar installation’s inverter; revealing that the transformer in that area was already set to too high a value, ie, with a maximum above 243.8 volts.
240V +/-6% is … 226V to 254V rounded
230V +10%/-6% … 216V to 253V rounded
Hence the upper limit has not changed except by 1V assuming you have a very high precision calibrated digital meter.
Did anything really change and does it matter? The following comes with a warning that any politician would be proud to own:
One punch line is that the revised standard has a preferred operating range of 230V +6%/-2%, IE 225V-244V. This is much tighter than many may experience.
The standard may have changed, compliance remains an unknown. Observations from two premises in Qld suggests nothing has changed, on that side of the border. If true it makes a joke of the justification including customer savings outlined in Table 1, Option 3.
A Uni of NSW study found that “Even though the nominal voltage on the grid is 230 volts, the researchers found 95 per cent of readings were higher than that level.” (my bolding)
“The Energy Security Board, which commissioned the UNSW study, said the findings pointed to a “material level of technical non-compliance” by the networks, and a “backlog of compliance issues” that needed work.”
It would seem that the gold plating of electicity networks was really done with fool’s gold.
Most of it was done to cater for a massive increase in air conditioning loads in urban areas, something which PV systems have somewhat eliminated. Lack of foresight means the gold plate is all in the wrong place!
In Queensland compliance, to voltage ranges specified in AS 61000 and AS 60038, is required by legislation (Act and Regulations).
Qld Electricity Act 1994
Section 28. It is also a condition of a generation authority that the generation entity must comply with all protocols, standards and codes applying to the entity under this Act.
Section 36. It is also a condition of a transmission authority that the transmission entity must comply with all protocols, standards, and codes applying to the entity under this Act.
Section 45. It is also a condition of a distribution authority that the distribution entity must comply with all protocols, standards, and codes applying to the entity under this Act.
Section 252 (1) A condition that may be imposed under this Act may require compliance with a protocol, standard, code, intergovernmental agreement or another agreement stated in the condition.
Schedule 2 Subject Matter for Regulations 2 Requirements and Standards
(b) electricity qualities, including for example, frequency, voltage and power factor;
Electricity Regulation 2006
Reg 11 Supply at low voltage
(4) The standard voltage for the supply, on or after 27 October 2018, of electricity at low voltage from a 3-phase system or a single phase system is the nominal voltage stated for the system in AS 60038.
Reg 12 Supply at high voltage
If an electricity entity agrees with a customer to supply electricity to the customer at high voltage, the agred voltage is the standard voltage for the supply.
(1) Supply of electricity by an electricity entity to a customer must be maintained at the standard voltage for the supply mentioned in section 11 or 12.
(3) … the supply is taken to be maintained at the standard voltage for the supply if the voltage at the consumer’s terminals -
(b) (i) is within the minimum preferred steady state median voltage and the maximum preferred steady state median voltage stated in AS 61000; or
(ii) if the voltage can not be maintained under subparagraph (i) - does not differ from the standard voltage by more than the percentage stated for the supply voltage range AS 60038.
(6) In this section - “AS 6100” means AS 6100.3.100 (Limits - Steady state voltage limits in public electricity systems) as in force form time to time.
Pardon my feeble attempt at satire and apologies to that time honoured question, ‘If a tree falls in a forest and no one is around to hear it, does it make a sound’
In Australia compliance is required by legislation (Act and Regulations).
Excepting nobody is responsible for checking, just an occasional questionnaire if that. Checked for conformance as required when commissioned and rarely again. If caught out the worst case penalty is to make it right, no conviction recorded, often at one’s convenience. If the power lines are not sparking and causing fires, appliances are not blowing up, and nobody has a recording meter on the line, is it over-voltage?
This is the section of the Electricity Regulations 2006 (QLD) relating to supply voltages…
s13 (3) For the supply of electricity at low voltage on or after 27 October 2018, the supply is taken to be maintained at the standard voltage for the supply if the voltage at a customer’s consumers terminals—
(a) for supply before 1 July 2020—does not differ from the standard voltage by more than the percentage stated for the supply voltage range in AS 60038; or
(i) is within the minimum preferred steady state median voltage and the maximum preferred steady state median voltage stated in AS 61000; or
(ii) if the voltage can not be maintained under subparagraph (i)—does not differ from the standard voltage by more than the percentage stated for the supply voltage range in AS 60038.
I know and you know, but that does not change how it is.
It seemed like a good idea at the time to point out that what Govt Regulations require and how Govt owned enterprises respond is open to question.
If it annoys, apologies. I am just stating my reality. I’m not grumbling or complaining. If the Qld ALP State Govt and Energex are not interested, I suspect the LNP is equally not interested in making solar PV more effective. I do live mostly in a very secure LNP electorate.
Is there scope to take up the challenge? There is. Where is it on my to do list? Somewhere down the list after getting the bush fire preparedness plan refreshed, and the latest batch of feral cats accounted for.
I suspect that the voltage export settings for many of the local PV system may have been set several years past to very loose limits. None of the neighbours have complained at loosing output, despite being connected to the same line or spur.
Gordon is correct. Most people are unaware of times when the grid voltage in their area is more than 6% above 230 V, ie above 243.8 V during day or night. And that includes the people and areas that don’t have solar.
There seems to be several ways of finding out:
if the high voltage from the grid causes an electrical appliance to malfunction or fail.
if the consumer puts something across the input they are getting from the grid that measures voltage (an inverter will do this)
if a study such as the UNSW study is commissioned (they looked at more than 12,000 households)
if the distribution authority has a smart transformer for that part of the grid (that transmits information back to grid control operations)
if the distribution authority has a dumb transformer for that part of the grid and sends a crew out to check voltages downstream from the transformer and what the transformer is doing.
Not sure what was done with respect to gold plating the ‘poles and wires’ when that was done, but maybe there aren’t enough smart transformers out in the grid.
Official document say that the effect of rooftop solar on the grid is (a) very low network loads, at accompanying low prices, when solar output is highest, and (b) a very high and fast ramp in the afternoon.
A search for a document backed up with evidence about the effect of rooftop solar on grid power quality, ie grid voltage, comes up blank except for the UNSW study.
Energy Queensland runs Powerlink, Energex, and ERGON. They are installing more Power Quality (PQ) monitors which provide real-time data on the state of the network in areas where no other measurements are available, and PQ Monitors are the primary source to report on compliance for 230V standard throughout the Energex network.
2020 update - Energex has four PQ monitoring programs monitoring programs (CA15, CA44, CA29 and CA48). One is a new distribution transformer monitoring program to replace the existing Maximum Demand Indicators with power quality (PQ) monitors; and a program that targets the installation of PQ monitors on distribution transformers where no monitoring devices were fitted previously, and the program specifically targets where all three phases require power quality monitoring.
Energex’s Power Quality (PQ) strategic proposal for the regulatory control period 2020/21-2024/25 says "Both the causes and consequences of PQ problems can be diverse and they will not be addressed by a single or multiple solution(s) at the LV network or customer connection level. Network solutions implemented at MV level can target to resolve PQ issues experienced by multiple LV networks.
Currently, the level of MV monitoring is not sufficient to develop solutions that can be implemented to resolve PQ issues potentially originating at 11kV network. Ad-hoc measurements are generally not suitable for this purpose as observation periods are limited and statistically weak, particularly given the daily and seasonal variation of loads and solar PV and the variations in network topology. "
There is another reason that the nominal voltage across Australia was changed and that is imported electrical goods are no longer specifically made for 240v. Australia being one of the last countries to have 240v as a mains voltage.
They can now come in as 220v and will safely “work” on the revised voltage. 216.2 to 253.0 volts.
The problem lies with older equipment that was specifically made for 240v.