VC08 Ground power conversion and grid interface
Depth of coverage
At its target depth of L3. What the depth levels mean.
What this layer covers
DC to AC conversion, transformers, protection, harmonics, fault ride-through, grid code compliance, the connection asset
Where it ends
Ends at the grid connection point
Deep area
This layer is studied in more depth than most. It belongs to the deep area Power electronics and ground segment.
Getting the power into the grid
The grid rules a receiving station would have to meet are published, but no paper found in a research index deals in its title or abstract with whether a station's converters could meet them. A receiving station on the ground turns the beam into direct current. Converters must then turn it into alternating current that meets the grid code, the technical rules for connecting to the grid. In Great Britain those rules already exist for other power stations. A separate security standard limits how much generation a fault on a plant's own connection may remove at once to 1,800 MW (CLM-0780). The grid code also sets how the plant must handle reactive power, which flows back and forth without doing useful work, and voltage dips (CLM-1107, CLM-1108). A separate recommendation sets planning levels on the network for harmonics, unwanted extra frequencies (CLM-0787). No such paper was found (CLM-0799).
Records
31 of the 34 records tagged to this layer are published. The rest are not yet published. A record is published only after a second reader has checked it and it has passed every publication check. What the gate checks.
| Record | In plain language | Tier | Confidence |
|---|---|---|---|
| CLM-0213 | The study assumes that connecting a ground receiving site to the electricity grid costs about GBP 150,000 for every megawatt of power the site handles. | T4 | HIGH |
| CLM-0214 | Six different solar-power-satellite designs each claim that turning the electricity collected on the ground into grid-ready power is 90 to 99% efficient, but nobody has independently checked these numbers. | T4 | HIGH |
| CLM-0215 | Any UK ground receiving station that wants to connect to the electricity grid must be able to supply or absorb a type of power called reactive power, under an existing UK grid rule. | T4 | HIGH |
| CLM-0216 | The UK's fast-response grid support services need a generator to react within seconds, at any moment over a 4-hour period. A ground receiving station on its own could not promise that, so it would need its own battery to offer this kind of service. | T4 | HIGH |
| CLM-0780 | The UK rules for connecting power stations set a hard limit on how much generation one fault may disconnect at once: 1800 MW for a fault on the station's own connection, and nothing at all for a fault on a single transmission line. | T1 | HIGH |
| CLM-0782 | UK rules limit the overhead line between a generating unit and the grid to 5 km for units producing at least 2000 gigawatt-hours a year and 20 km otherwise. A 2 gigawatt plant counted as one unit would cross that threshold even if it ran only about 11 per cent of the time, but the rules define a generating unit as any apparatus which produces electricity, and counted that way a receiving site made of many converters would fall under the 20 km limit. Which reading applies is not settled. | T0 | HIGH |
| CLM-0783 | Under Great Britain's grid code as the system operator's 2024 guidance describes it, an inverter-based generator must be able to export or import reactive power equal to about a third of its rated output, usually measured where it joins the grid, and the guidance says it should reach 90 per cent of a requested change within one second. | T3 | HIGH |
| CLM-0786 | In December 2025 the UK system operator changed its own connection standard to allow a single large direct-current converter to carry more power, because the old 1320 megawatt cap was forcing offshore wind farms to build extra cables, and it priced the extra frequency support at about 12 million pounds a year. | T3 | HIGH |
| CLM-0787 | The UK harmonic planning levels for networks above 230 kV set total waveform distortion at 3 per cent, with the largest single-harmonic level being 2 per cent at the fifth and seventh harmonics. These are levels for the network as a whole, and each connection gets only a share of them. The document is a recommendation, and it is careful to say which of its words are mandatory. | T1 | HIGH |
| CLM-0788 | If the ground station has several hundred converter units and their diversity is declared, the harmonics standard lets their high-frequency distortion partly cancel while their low-frequency distortion adds up directly, so the hardest limits to meet are on the low-order harmonics below the fifth and not on the high-frequency switching harmonics that inverter designers usually worry about. Without that declaration the standard requires all their distortion to be added up directly, and the low-order harmonics are no longer singled out. | T0 | MED |
| CLM-0789 | A UK inverter-based generator must stay connected through a complete loss of grid voltage lasting up to 140 milliseconds, then get back to at least 90 per cent of its output within half a second, and must remain stable for up to 30 minutes afterwards. | T3 | HIGH |
| CLM-0790 | Great Britain does not oblige an inverter-based generator to behave like a synchronous machine; it pays for that behaviour through a market. Plants that do offer it face a demanding specification, including being able to keep operating when the grid at its connection point has a short-circuit level of zero. | T3 | HIGH |
| CLM-0791 | In 2024 the EU was moving towards putting grid-forming behaviour into its connection code, following a December 2023 recommendation, but the draft wording required it only where the national system operator asks for it. Britain and Australia already had their own versions. | T3 | HIGH |
| CLM-0792 | Under the UK's retained version of the EU connection code, any generator connecting at 110,000 volts or more, or above 75 megawatts, faces the strictest category of requirements. Its reactive power envelope is capped, and synthetic inertia is something the system operator may ask for, not something the generator must have. | T1 | HIGH |
| CLM-0793 | Britain's system operator plans to run the grid with less spinning inertia, and it sets that limit from the size of the biggest single generator loss it must survive, currently 1800 megawatts. | T3 | HIGH |
| CLM-0795 | Britain's system operator says that at the lower inertia level it is moving to, losing 2000 megawatts at once would be enough to start disconnecting customers, and losing 3.3 gigawatts at once could cause a nationwide blackout. | T3 | HIGH |
| CLM-0796 | Britain's system operator says its grid needs both spinning inertia and short-circuit strength, and gives a scale: a single 2 gigawatt coal station used to supply over 6,500 megavolt-amperes of that strength. | T3 | HIGH |
| CLM-0797 | In December 2025 Britain's system operator said that 283 gigawatts of generation and storage, out of more than 700 gigawatts that had been waiting to connect, would be prioritised for connection, split between projects needed by 2030 and by 2035. | T6 | LOW |
| CLM-0798 | The American standard often named as the comparator, IEEE 1547, covers generators joining local distribution networks. A gigawatt-scale ground station would join the high-voltage transmission network instead, so a different standard applies, and that one was not obtained. | T4 | MED |
| CLM-0799 | A search of a large research index on 4 September 2026 found 2551 papers on space-based solar power and not one whose title or summary mentions grid codes, fault ride-through, reactive power, harmonic distortion, grid-forming or power quality. | T0 | MED |
| CLM-0800 | A 2025 power-engineering paper does model space-derived solar power inside an electricity network, but it uses a nine-bus textbook test system and only steady-state calculations, so it does not test any of the connection rules a real plant would have to meet. | T2 | HIGH |
| CLM-1081 | The people who would have to buy the power said in 1980 that a five-gigawatt block that could vanish within minutes in the spring and autumn eclipse periods might need six gigawatts of standby, that the ground station would lose two hundred thousand diodes a year, and that American utilities were unlikely to own one until there were some ten. | T3 | HIGH |
| CLM-1098 | The 1977 plan for a cheap rectenna was two flat planes, the front one doing all the work inside a metal shroud that is also the structure, wired in series to reach a thousand volts for the inverters; a five-element piece was built and worked, and the report says the next thing to build is a thousand-volt section. | T3 | HIGH |
| CLM-1107 | The actual Grid Code figure is not a flat 0.95 power factor at all voltages: the plant must push reactive power out when the grid voltage sags towards 0.9 and absorb it when the voltage rises towards 1.1, and full capability both ways is only demanded in a narrow band around nominal. At part load the requirement is a third of rated power either way, easing on the absorbing side below half load. | T1 | HIGH |
| CLM-1108 | After the first 140 milliseconds, the rule is a line on a chart: the lower the grid voltage sags, the shorter the time the plant must hold on, from 0.14 seconds near a full collapse out to three minutes at a 15 per cent sag. Then it has to be back to 90 per cent output within a second of the voltage recovering, and stay on for half an hour. | T1 | HIGH |
| CLM-1109 | The rulebook says the same as the guidance: nobody has to make their inverters behave like a rotating machine, but the grid needs enough plants that do, and it pays for them. If a plant offers it, it must be able to run into a dead network, feed its full rated current into a short circuit for the fault-clearing time, and be tuned within a stated damping range. | T1 | HIGH |
| CLM-1210 | Britain's grid runs at 50 Hz, normally kept between 49.5 and 50.5 Hz. A power station connected to it, which would include a rectenna, must keep running between 49 and 51 Hz without limit, and for set minimum times further out, down to 47 Hz and up to 52 Hz. | T1 | HIGH |
| CLM-1211 | Britain's main transmission grid runs at 400 kV and 275 kV, and parts of the 132 kV network in Scotland. On the 400 kV network the voltage normally stays within 5 per cent of its nominal value and never beyond 10 per cent outside abnormal conditions. The rules read do not say how the connection voltage for a given plant is chosen. | T1 | HIGH |
| CLM-1386 | Great Britain's grid rules put any generator joining the network at 110,000 volts or more into their top class, Type D. A gigawatt ground receiving station would join at 275,000 or 400,000 volts, so it would be Type D. | T1 | MED |
| CLM-1486 | A 1977 NASA study of how receiving stations would join the US power grid looked at two kinds of shadow. For about six weeks around each equinox, the Earth would shade each satellite once a night near midnight; the study judged this easy to cover, because demand then is about half its peak. If more than a hundred satellites were built, they would also shade each other each morning and evening, close to peak demand. By the study's table, that would cut the number of five-gigawatt receiving stations the US grids could take in 2025 from about 360 to about 60. The study added that direct-current links between the regional grids would largely remove the problem, but gave no figures for that. | T3 | MED |
| CLM-1487 | In Britain, the amount of fast back-up power kept ready depends mainly on the biggest single block of power that could be lost at once; the rules do not set it by fuel. So a space solar station would need about the same fast back-up as a gas power station whose biggest single loss is the same size. A 2 GW space plant would be a bigger single loss than the 1,800 MW Britain now plans for, if one fault could take all of it. A satellite in geostationary orbit also passes through the Earth's shadow each night for about six weeks around each spring and autumn equinox, for up to about 70 minutes. Those times can be predicted exactly, and other power stations would have to cover them. | T3 | MED |