Page 47 - From Smart Grid to Internet of Energy

36 From smart grid to internet of energy

disturbances or provide instant information to manage real time pricing and
detecting losses and fraud usage if applicable.
The power flow is unidirectional in conventional grid where the power
generated at power plants are supplied to consumers over transmission and
distribution networks. The deployment and distribution of power is managed
by using distribution substations where medium and low voltage levels are
obtained. The improvements on distributed generation and penetration of RESs
forced the conventional grid infrastructure to provide two-way power flow.
Therefore, efficient and reliable operation of a such grid transformation brought
some monitoring and control requirements. The transformed grid infrastructure
requires secure, interoperable and cost-effective use of sources by the contribu-
tion of information and two-way communication technologies [26]. The funda-
mental structure of a power network transformation to smart grid has been
shown in Fig. 1.9 with source and load types. Although the conventional gen-
eration is based on centralized power plants as CHP, large scale hydroelectric
power plants, and nuclear power plants where most of them use fossil-fuels,
smart grid infrastructure allows decentralized generation and microgrid power
plants. In a such scenario, all the sources should be integrated to widespread
monitoring and control system. Thus, generation and consumption balance
are effectively managed and DSM requirements are met in a reliable way.
The power control and management systems include demand forecasting
(DF), automatic generation control (AGC), automatic voltage regulator
(AVR), and load frequency control (LFC). The challenges and requirements
for modernizing the conventional power network are summarized by four titles
as environmental challenges, consumer requirements, infrastructure challenges,
and innovative technologies in [27]. On the other hand, the proposed solutions
to address these challenges are listed as digitalization, intelligence, flexibility,
resiliency, sustainability, and customization. A collection of smart grid appli-
cations has been presented in Table 1.5 according to power system level,
measurement and control applications, ICT technologies and used device types.
The critical applications are real time monitoring, power plant control, RES and
alternative energy sources integration, distributed generation monitoring and
quality of service (QoS) detection in generation level of smart grid. These appli-
cations can be performed by using Metropolitan Area Network (MAN), WAN,
LAN and SCADA networks to provide power control and DSM measurements.
The most important devices used to ensure these tasks are AVRs, PMUs, IEDs
and smart transformers in generation level.
The transmission level applications include substation automation, trans-
mission line control and monitoring, and power monitoring applications based
on power loss and leakage measurements, fault localization and prevention,
phasor measurements, network topology analyses, and security monitoring.
These operations are performed by use of PMU, FPI, RTU, and GPS systems
with WAN and LAN communications or EMS and SCADA systems. The sub-
station automation is required in addition to smart transformer control, DLC,
AMI and AMR applications in distribution level.