Smart Grid Operational functions and Control Challenges by Implementing SSSC Tailored to Optimize performance in between Qatar and KSA on the GCC Electrical-power grid

A R T I C L E I N F O A B S T R A C T Article history: Received: 19 August, 2017 Accepted: 06 September, 2017 Online: 30 September, 2017 This research work is novel technique to control and optimize SSSC (Subsynchronous Series Controller) functions with degree of precision in between Qatar and Kingdom of Saudi Arabia. The SSSC model developed and simulated in order to identify and determine its control and functioning parameters by introducing new tuning parameters based on that the SSSC can be adjusted stringently to witness desired results lead to address outstanding reactive power management issue. The proposed new parameters are contributing significantly to control SSSC functions in multiple directions in a power system network in between QATAR and Kingdom of Saudi Arabia at different time-based transmission contingencies on the GCC Electrical-power grid. Strategically, the SSSC capacity and capability can be utilized fully in between Qatar and Kingdom of Saudi Arabia by introducing and optimizing its control and tuning parameters more tangibly under both steady and dynamic states


Introduction
The SSSC has operational controllability results are clearly indicating that introduction of SSSC in between Qatar and Kingdom of Saudi Arabia power network will equitably improve the power system loadability, curtailing the losses and valueadded sustainability of the power system enactment by addressing control and operational issue throughout the GCC Electricalpower grid.
Hereafter, new SSSC optimization technique can thus be magnificently expended for this type of power system process optimization. This work published in 13 th the IET International AC/DC Conference held in Manchester, February 14-16, 2017. Whereas a SSSC determines and validates the three control and effective limits which have been made-to-order at (minimum (+/-) medium (+/-), and maximum (+/-) compensation. These rheostats functioning limits are regulated by constituting their consequent PI control-values by exercising D.J. Cooper PID regulator Performance to achieve the following [1].
Therefore, FACTS Controllers are convincing candidate technology options centered on that following benefits can be perceived.

GCC Electrical-power grid background
The GCC power-grid is constituted and employed into eight premeditated power system operational directions in order to meet national and industrial customers necessities in a consistent and viable demeanors at the GCC Electrical-power grid-network as shown in Figure 1 as considered and described with facts and figures, this is also published in [1] .

SSSC Operational Analyses
Principally, the SSSC-series counterbalance device location is not very much perilous it can be employed anyplace on the GCC Electrical-power grid. In this case the SSSC has been retained at the borderline to decrease the power-line transmission impedance unnaturally by SSSC which is controlling to upsurge the power flow in the power transmission system in (5) and (6) determine how much line impedance (XC) has been Controlled and Managed after employing series but stable capacitor's Kseries factor. SSSC encompasses of capacitors and reactors to diverge the power-line impedance on domineering need basis vigorously. Predominantly, the SSSC injects the voltage in a series into the power transmission network at the midpoint of Kingdom of Saudi Arabia and Qatar whereas instilled/injected the voltage at midpoint Vr has been computed in (7). The SSSC stipulates or expends reactive-power in capacitive/inductive control-mode of functions on the GCC power-grid, wherein the SSSC instilled/injected voltage in phase quadrature with the line current of the power network.
Figure 2 denotes maroon trend in the graphical presentation of the SSSC processes in capacitive and inductive mode of functions. Practically, blue trends denote how much real power transferred can transferred when electrical-power transmission network compensation carried-out capacitive, inductive mode of operations or neutral without any compensation factor. Figure 3 signifies that a SSSC has a main and great influence on power steadiness and load flow, but ithas limited impact on voltage profile enhancement as exhibited in (28) that Vm, Vs, Vr has negligible or no effect with SSSC [2].

By employing Series Fixed Capacitor to upsurge the Power on the GCC Electrical-power grid
Herein determined conjectural power can be dispensed and distributed without conservative or non-conventional series compensation, the voltage structured transitorily but not vigorously and unvaryingly which is outfitted at 800 km long electrical-power transmission network from Kingdom of Saudi Arabia to Qatar or vice versa along with its attendant substations. Now if series capacitor is connected at midpoint voltage as stated in Figure 3 to resource and expend sufficient reactive power to counterbalance as prerequisite. Equation (5) expended to compute series compensation factor to convalesce the power system steadiness and double the power at power transmission lines reactance XC= 136.626 Ohms as intended in (6) and (7) [3].
Equation (7) reveals the concentrated power by adapting power transmission line reactance by series capacitor Units.

By implementing Series-Capacitor to upsurge the Power on the GCC Electrical-power grid
The SSSC has a tremendous competence to upturn the electrical Power flow and improve dynamic steadiness to supplant usual and uneconomical fixed series capacitors are expended to govern the prerequisite reactive current at midpoint in between Qatar and Kingdom of Saudi Arabia for recompense [4].
Equation (26) expressed the Quadratic function as detailed below with factors.
Equation (27) and (28) Quadratic roles are defined and extracted and resultant in (29) = − 4 ± √8 2 + 2 4 (29) Equation (29)  Equation (34) signifies the concentrated electrical power dispensed and distributed in the GCC Electrical-power grid by retaining SSSC to uphold persistent Vr vigorously in the Midpoint of QATAR and Kingdom of Saudi Arabia as illustrated in Figure  4 [5].  Figure 7. SSSC connected at the midpoint and instilled/injected VQ toward VR Figure 5: signifies that counterbalance device employed in the middle of the of the power transmission line, this is voltage source only dispense reactive electrical power not a real power. Figure 6 displays the influence of location if counterbalance device employment on voltage profile, the voltage on left side of the counterbalance device would be VQL and right side VQR. Figure 7 illustrates that the series counterbalance device employed in the middle the worst voltage-profile occurred at each side of the counterbalance device, whereas the voltage-profile vector aligns with the current vector [5]. Therefore, the midpoint voltage-profile is the same with/without SSSC functions as exhibited in (37)

Maximum level Vr voltage-injection
It has been simulated and authenticated that further real power can be up-surged in the power transmission line to touch its design specification by up-surging the SSSC compensation factor from 50% to 65% reactive voltage instilled/injected voltage would be 0.8864pu which is equivalent to 204kV and current Im = 2.1pu and = .° will activate consequently at different functioning condition total 1200MW power will be produced and distributed on the GCC electrical-Electrical-power grid. This is known as a determined compensation by implementing a SSSC and its compensation factor from 50% to 65% to obtained projected power produced and delivered in the electrical power transmission network on the GCC electrical-Electrical-power grid.

Medium level Vr voltage-injection
As simulated by Matlab/SIMULINK and scientific/ mathematical model Vr instilled/injected voltage 0.5936pu which is uniform and match to 137kV at 50% SSSC reactive voltage compensation whereas the midpoint current Im = 1.4459pu, and = .° will activate consequently in this functioning circumstance to a total 1079 MW power which can be produced and distributed on the GCC Electrical-power grid as validated by the results. Infact, QATAR and Kingdom of Saudi Arabia system has been devised to produce and distribute concentrated 1200MW electrical-power in the GCC Electrical-power grid during a peak load, therefore Margin is obtainable to upsurge the power up to its projected specification. This is also identified as a medium compensation by a SSSC compensation factor from 20% to 50%. Therefore, the Control function block expended to readjust PI controller response as exhibited in Figure 10 to diverge the firing angle of the Thyrister control [7].

Minimum level Vr voltage-Injection
In the third challenge of operations, further this model was simulated and authenticated by exercising SSSC Controller. At minimum compensation of the SSSC compensation real power reduce considerably in the power transmission line to touch its projected specification by decreasing the SSSC compensation factor from 5% to 20% reactive voltage instilled/injected voltage would be 0.3710pu which is equal to 86.67kV and current Im = 0.974pu and = .° will activate consequently in this functioning condition total 986MW power will be produced and distributed on the GCC Electrical-power grid. This is identified as a minutest compensation by using a SSSC Controller and its compensation factor from 5 to 20% to achieve projected electrical power delivery of transmission network on the GCC Electricalpower grid. As instilled/injected voltage up-surged based on compensation from 5% to 20% there is considerable power flow and steadiness enhancement but very insignificant influence on voltage-profile as verified simulated consequences in Figure 8 (a) reactive power injection-waveform 8(b) indicates the total power delivered in between Qatar and Kingdom of Saudi Arabia, this is also computed in equation (34). The PI controller configured and demonstrated its operational response in Figure 9. Detailed configuration discussed as given in the appendices [8].

Conclusion
Fundamental creativity of the SSSC application in the GCC Electrical-power grid transmission line compensation is the subject of extensive significance. In this study, it has been computed and simulated how much maximum power can be produced and distributed in between QATAR and Kingdom of Saudi Arabia without any process vagueness. It has been reasonable how much reactance must be provided by the series capacitance to double the power supply in between Qatar and Kingdom of Saudi Arabia. It also has been also identified and unwavering amount of reactive voltage to be instilled/injected in between Qatar and Kingdom of Saudi Arabia in order to provide concentrated power delivery on the GCC Electrical-Power grid.
If the load angle as decreased below from 65 to 0 amount of electrical-power will be produced by SSSC in between Qatar and Kingdom of Saudi Arabia. Herein, the GCC electrical-power network will exclusively upsurge the power system loadability, decrease the losses and improve sustainability of the electricalpower system functioning. The results also illustrates that SSSC is multipurpose equipment with stupendous active capability to improve power system stability margin on the GCC Electricalpower grid. Based on these results, SSSC is a very strongcandidate to be instigated at GCC Electrical-power grid. It also demonstrates optimistic influence on neighboring countries' power system functions at the GCC Electrical-power grid.

Conflict of Interest
No conflict of interest in this paper has been identified.