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distributed photovoltaic is developing very rapidly. There are also some irregular problems in
, such as the lack of strict implementation of standards and specifications, the overcapacity access of distribution transformer , and the excessive power quality of , etc., which have a negative impact on the operation of the power grid and safe power supply.
Recently, Hebei Provincial Development and Reform Commission issued the "Notice on Strengthening the Management of Distributed Photovoltaic Power Generation on Roofs" (hereinafter referred to as the "Notice"), reflecting the pain points and problems in the process of distributed photovoltaic construction.
Several key points are analyzed as follows.
insists on local consumption and balance
The fundamental feature of distributed power supplies is local consumption and balance
The fundamental feature of distributed power supplies is local consumption and balance till nearby.
But now, there is a time mismatch between power generation during the day and electricity consumption at night.
Objectively, there is distributed photovoltaic power generation and a large number of power transmission networks are being used. In some areas, there is even a possibility of reverse transmission of 110kV and 220kV power grids. This is obviously inconsistent with the essential requirements of distributed power supplies. This brings problems to the control of the power grid, line loss, voltage, reactive power, etc.
Therefore, the "Notice" emphasizes that the development and construction of distributed photovoltaic roofs of
should be coordinated with the development of power grid construction and electricity load in the development area to avoid long-distance and cross-regional power transmission.
explicitly has the access capacity
main transformer or distribution transformer can access distributed photovoltaic capacity. In principle, the evaluation should be carried out in accordance with the "Guidelines for the Assessment of the Carrier Capacity of Distributed Power Access Power Grid" (DL/T 2041). For related content, please refer to a previous article "Distributed Photovoltaic Access, Measurement of Grid Carrying Capacity". However, this method lacks flexibility and convenience in practice, which causes operational problems.
Therefore, the "Notice" clearly states that over-capacity access is strictly prohibited by
, and the photovoltaic capacity (including registered capacity under construction or to be built) connected to the main transformer of the power grid (distribution transformer) at all levels shall not exceed 80% of the rated capacity of of the equipment .
Solution for insufficient distribution capacity
distributed photovoltaics are mostly connected to the low voltage side of the distribution transformer.
What should I do if the capacity of the configuration variable is insufficient?
This situation is due to insufficient load-bearing capacity of the power grid. According to relevant specifications, distributed photovoltaics should be slowed down, and the power grid should be transformed at the same time.
If you still need access, you can consider directly accessing the 10 kV voltage level to bypass the limit of distribution capacity.
Therefore, the "Notice" provides another access plan. The photovoltaic capacity (including the registered capacity under construction or to be built) of
has reached 80% of the rated capacity of the equipment. If the superior power grid still has an open capacity, it should be accessed in a 10 kV special-transformation mode in accordance with the requirements of the "Guidelines for the Construction of Distributed Photovoltaics (Trial)".
Of course, it is a basic requirement for the grid to actively transform power grid equipment.
Therefore, the "Notice" requires that in principle, the funds for power grid transformation and upgrading should be given priority to the roof photovoltaic pilot area of the entire county.
Standardized project establishment procedures
Distributed photovoltaic construction unit leases power customer roofs and installs distributed photovoltaics, which is a common construction model.
However, some construction units require power customers to carry out distributed photovoltaic installation. In this way, the contractual relationship between the construction party, power customers, and power grid companies is both complex and has doubts about authenticity, and it also involves sensitive issues such as fee payment. There is a tendency for uncertainty in the relationship between the parties.
Therefore, the "Notice" clearly states that if the network connection application materials submitted by
in the name of a natural person, if the agreement to lease a natural person roof in the name of an enterprise, the relevant enterprise shall be uniformly registered and shall be carried out in accordance with the non-natural person's acceptance procedures.
Distributed photovoltaics should be accepted
Any power construction project should be accepted first and then put into operation. Distributed photovoltaics are no exception.
Therefore, the "Notice" emphasizes that the acceptance of distributed photovoltaic projects for
household roofs is mainly organized and carried out by project owners and power grid companies; the acceptance of distributed photovoltaic projects for industrial and commercial roofs is organized and carried out by county-level energy authorities or commissioned by third-party testing institutions, and the power grid companies participate. Roof distributed photovoltaic projects that have not been accepted or have failed the acceptance shall not be connected to the grid.
Distributed photovoltaic scheduling control
In the early stage of distributed photovoltaic construction, the capacity was small and the quantity was not large, so the impact on the power grid was minimal. The power grid has insufficient monitoring capabilities for distributed photovoltaic power generation, and there is a lack of policy basis for scheduling and control.
But the number and installed capacity of distributed photovoltaic equipment are huge now, so it must be given enough attention.
At the same time, during the construction process, inverter manufacturers, integrators, construction parties and other links have developed various system functions to measure and even control distributed photovoltaics.
measurement is fine, but control poses a huge hidden danger to the safe and stable operation of the power grid. Because of the massive distributed photovoltaics, they are essentially no different from large power generation units.
Imagine whether power grid security can tolerate a large power plant being away from unified dispatch?
Therefore, the "Notice" requires that the
roof distributed photovoltaic power generation system should have real-time monitoring and control functions to meet the relevant specifications and requirements of power grid access, and be connected to the grid for trial operation after debugging and testing, and be uniformly dispatched and controlled by the power grid. Without the permission of relevant government departments, manufacturers, integrators, and installation units of roof distributed photovoltaic power generation system shall not leave remote control interfaces or retain corresponding capabilities.
Distributed photovoltaics have broad prospects, but normativeness is a prerequisite for healthy development, so everyone pays attention.
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