Page 160 - Decision Making Applications in Modern Power Systems

124 Decision Making Applications in Modern Power Systems

current produced by the generator to an AC current compatible to the grid
frequency.
Small PV systems in homes are usually single-phased. Unless PVs are
uniformly distributed among the phases, the imbalance may increase, result-
ing, for example, in an increase of the neutral current in the cables and a
voltage increase at the point of common coupling (PCC) [9]. System imbal-
ance can drastically alter and affect the operation of induction motors, elec-
tronic devices, and equipment for voltage regulation.
Finally, the clear majority of PV systems are connected to the system
through inverters with unitary power factor (PF). The main reason is eco-
nomical—the PV system should inject as much active power as possible for
maximum revenue to the PV owner, and the grid has to supply the reactive
power required by the load. The PF at the customer’s PCC may be reduced,
which is measured as a surplus of reactive power, subjecting the consumer to
tariff charges for low PF.

5.2.1.4 Operation of the power grid
In order to adapt to the needs of the new electrical network with high DG
penetration, additional investments are required, for example, the update of
protection schemes and the necessity to make enough operational reserve
capacity. Such investments should ensure the user’s electricity reliability and
suitability of lines and substations. Also, policies should promote a fair eval-
uation of the risks over all stakeholders and guarantee an efficient use of the
power system for DG [10].
Procedures related to the connection control of DGs to the grid and the
business models involving DG (e.g., demand response, feed-in, and time-of-
use tariffs) are still subjects of ongoing discussions and research.

5.2.1.5 Socioeconomic impact problems
Not only technical problems arise with the change in the distribution system
and dissemination of DG, socioeconomic impacts must also be analyzed in
the context of changes. The consequences and costs of problems related to
the increased level of penetration of distributed systems may affect a portion
of the population that does not have financial access to such resources, so
there is a concern that the new distribution network does not become an
instrument to promote social balance.
On the side of utilities, there are also concerns about revenue losses and
increased costs with network depreciation and maintenance [1]. The philoso-
phy of technology discussed in Ref. [11] helps one to provoke a critical
reflection about the socioeconomic impacts of engineering. Several issues
and challenges are described in the literature and should be considered in the
analysis of distribution networks.