Advanced Control Techniques for Enhance the Power

——ONLINE FIRST(NOT Peer-Reviewed)——

Title：Advanced Control Techniques for Enhance the Power System Stability at OOS Condition Author：Amer Nasr A. Elghaffar, Ali M. Eltamaly, Yehia Sayed, Abu-Hashema M. Elsayed Institute/Affiliation：Minia University, Mansoura University Received：2018-04-28 Online First：2018-09-20 Process：1、First trial(Field and check) 2、Peer review 3、Editing and three trials 4、Published online

PiscoMed Publishing Pte. Ltd. Singapore Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Advanced Control Techniques for Enhance the Power System Stability at OOS Condition Ali Eltamaly1, Amer Nasr A. Elghaffar2, Yehia Sayed2 and Abu-Hashema M. El-Sayed2 1 Electrical Engineering Department, Mansoura University, Mansoura, Egypt 2 Electrical engineering Department, Minia University, Minia, Egypt [email protected], [email protected]

Abstract: The stability of the power system is the accurate operation of the electric grid by recovering a state of operating balance after being subjected to an abnormal condition such as faults, line switching, load rejection, and loss of excitation. Protective equipment's in high voltage substations should be providing fast, reliable localizes faults and selectivity. But, some abnormal condition in power system such as out-of-step (OOS) condition which mechanical power for the generator not equalized with electrical power for the load which is not a real fault, but the protection equipment’s will consider this condition is a fault. This situation will cause the loss of synchronism between areas within the power system or between interconnected systems that's will lead to blackout for the national grid. This paper study the OOS condition, philosophy of protection relay device and how to overcome this condition by optimal method to avoid the false operation for distance function by Out of Step Blocking (OSB) to improve stability of power system by using the advanced protection relay. Key words: Power System, OOS, Advanced Relay and Transient. 1. Introduction It’s important to use the protection system with Over-Head Transmission Lines (OHTL), since, it’s mostly extended across large geographical regions to transport the power from generators to load centers. So, it is possible to simulate faults along the OHTL which ranges from conduction that failure to loss of insulation [1] [2]. Power Swing Condition (PSC) can be defined as a variation in three phase power equalized for voltage and also three phase current flow. The power flow from generator to the grid is a high dynamic network connecting via (OHTL). Fig. 1 shows the single line diagram for the two sources power system, at stable conditions in power system, its operate very compact to their nominal frequency (50 or 60 Hz) and typically maintain absolute voltage differences varies between 5%. The frequency in stable system varies between ± 0.02 Hz. The equalized in active power and reactive power between power generated and consumed exists during stable operating conditions [13]. The power flow in the power system, its effect by any change or unstable in the loads or power generated, this change in power flow still in the network until reach to equalization between load demand and power generation. These changes conditions in power flow happen more times, but it's immediately compensated by control systems, and normally have no detrimental effect on the power grid or its protective systems [3]. There are some abnormal conditions in power system, that’s may lead to loss of synchronism between power generator and the rest of the utility system for the load, or between adjacent utility interconnected with power systems. At out of synchronism condition in power system, it is important to separate immediately the power generator or the system areas that’s operating asynchronously, this separation to avoid widespread outages or lead to black out and equipment damage. An effective mitigating way to contain such a disturbance is done through control in the power system using the OOS function in protection systems. Researchers study OOS condition in power system by adjusting the IEDs to detect OOS by the time interval required by the apparent impedance locus to cross the two characteristics 1 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

(buffer area), if the time exceeds a specified value, then the power swing blocking function is initiated [4]. But this method is not easily to simulate. Also, may lead to false operation for OSB at some actions in power system such as starting inrush current. This inrush current generates at energizing the power transformer that’s a one from loads for the OHL which need to design the OOS. So, this paper shows optimum design for distance protection function to control system by using IEDs that is achieved with an Out-Of-Step Blocking (OSB). However, OSB systems must be balanced with Out-Of-Step Tripping (OST) of distance relay elements or other IEDs functions to operate during unstable power swings. Using OSB by the design that's shown in this paper will prevent system black out or separate un-synchronizing area by false operation [5].

Fig. 1 Single line diagram for two sources power system 2. Distance Protection Performance Many years, the world have been successfully used for distance protection functions with OHTL [18]. It's considered the main protection for OHTL. The development in the protection relays from electromechanical relay and solid-state relays with mho quadrature to Intelligent Electronic Device (IEDs), numerical relay is the important factor in the widespread acceptance of this type of protection functions at different voltage levels all over the world. The first zone in distance function protection is used to provide primary high-speed protection which operates instantaneous, to a significant portion of the transmission line. The second zone is used to cover the rest of the protected line and provide some backup for the remote end bus [18] [19]. The third zone is the backup protection for the first and second zone for all the lines connected to the remote end bus. The applications for the distance function in IEDs is required for understanding of operating principles, with consideration the factors that affect on the performance of the protection relays under different abnormal conditions in power system. The setting of distance IEDs should ensure that the relay is not going to operate when not required and will operate, only when it’s necessary [18]. IEDs distance protection effectively measures the impedance between the relay location and the fault by measuring voltage and current in the transmission line. If the resistance of the fault is low, the impedance calculated is proportional to the distance from the current transformer which supplied the distance relay to the fault [25]. A distance protection function in IEDs is designed to protect the faults occurring in OHTL between the current transformer location, the selected reach point and remains stable for all faults outside this region or zones. The adjusted time for zones is designed by stepped distance scheme this ensures adequate discrimination for faults that may occur between different line stations [10]. 3. Analysis of symmetrical fault in Power system To analyze the fault, it’s important to simulate the fault in three components that’s positive sequence and negative sequence and zero sequence. Fig. 2a shows the positive sequence components are equal in magnitude values and the angle difference between each phase by 120 degrees with the same sequence as the original phases, also the currents and voltages follow the same cycle in typical counter clockwise rotation electrical system that’s called the “abc”. Fig. 2b shows the negative sequence components that’s equalized in magnitude, 2 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

the phase shift between phases is 120o and its opposite phase sequence from the original system that’s identified as “acb”. Fig. 4c shows the zero sequence components that’s three-phase equalized in magnitude and the phase shift between phases is zero. The zero sequence components are not presented at symmetrical fault [28-29].

Fig. 2 Analyze the sequence component in the power system Firstly, the Change in magnitude: a = 1∠120° = −0.5 + j0.866 (1) 2 a = 1∠240° = −0.5 − j0.866 (2) 3 a = 1∠360° = 1 + j0 (3) From these equations, useful combinations can be derived 1 + a + a2 = 0 1 − a2 = √3∠30° (4) Or 1 − a = √3∠ − 30° a2 − a = √3∠270° (5) Or a − a2 = √3∠90° (6) Any three-phase system of phasors will always be the sum of the three components. Positive sequence voltage is: Va1 Vb1 Vc1 Negative sequence voltage is: Va2 Vb2 Vc2 Zero sequence voltage is: Va0 Vb0 Vc0 The original system phase components can be presented from Va, Vb and Vc

3 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Va = Va0 + Va1 + Va2 [Vb = Vb0 + Vb1 + Vb2 ] (7) Vc = Vc0 + Vc1 + Vc2 From equations (1) to (5) Zero sequence component Va0 = Vb0 = Vc0 Positive sequence component Vb1 = a2 Va1 Vc1 = a Va1 Negative sequence component Vb2 = a Va2 Vc2 = a2 Va2 Va, Vb and Vc can be expressed in terms of phase “a” components only as: Va = Va0 + Va1 + Va2 Vb = Va0 + a2 Va1 + a Va2 Vc = Va0 + a Va1 + a2 Va2 This equation can be accomplished in a matrix form: Va 1 1 1 Va0 [Vb ] = [1 a2 a ] [Va1 ] (8) 2 Vc 1 a a Va2 Equation (8) can be written as: 1 1 1 A = [1 a2 a ] 1 a a2 Va Va0 [Vb ] = A [Va1 ] Vc Va2 This equation can be reversed in order to obtain the positive, negative and zero sequences from the system phasors Va0 Va −1 [Va1 ] = A [Vb ] (9) Va2 Vc Where, 1 1 1 1 A−1 = 3 [1 a a2 ] 1 a2 a 3.1

Symmetrical fault analysis

4 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Three-phase fault is known the symmetrical fault where the voltage is zero in the fault site. Fig. 3 shows the general simulation for the symmetrical fault, Fig. 4 shows the sequence diagram of a symmetrical fault [2829].

Fig. 3 General simulation of a three-phase fault

Fig. 4 Sequence diagram of a symmetrical fault The corresponding currents for each of the sequences is: 𝐼𝑎0 = 0 (10) 𝐼𝑎2 = 0 (11) 𝐼𝑎1 =

1 ∠0 𝑍1 +𝑍𝑓

(12) 5

Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

At fault impedance Zf is zero, 1 ∠0 𝐼𝑎1 = 𝑍 1

Substituted into equation (13) 𝐼𝑎𝑓 0 1 1 1 [𝐼𝑏𝑓 ] = [1 𝑎2 𝑎 ] [𝐼𝑎1 ] 𝐼𝑐𝑓 1 𝑎 𝑎2 0 So, by solving the equations: 𝐼𝑎𝑓 = 𝐼𝑏𝑓 = 𝐼𝑐𝑓 =

(13)

1 ∠0 𝑍1 1 ∠240 𝑍1 1 ∠120 𝑍1

And the phase Voltage is: 𝑉𝑎𝑓 = 𝑉𝑏𝑓 = 𝑉𝑐𝑓 = 0 𝑉𝑎0 = 𝑉𝑎1 = 𝑉𝑎2 = 0

(14) (15)

4. Out of Step and Distance Relaying In this lecture, we will introduce the concept of power swings. It will be shown that the post fault power swings may encroach the relay characteristics. This can lead to nuisance tripping of distance relays which can sacrifice the system security. 4.1 Transient stable power system During steady state operations of power system, the output of electric power produces an electric torque that equalized with the mechanical torque which applied to the rotor shaft for the generator. Fig. 5 shows the power angle curve for the fig. 1 in power system. Generator rotor runs at a constant speed at balance between electric power and mechanical torques. At fault condition, the amount of power output from generator will be reduced, but the mechanical torque can’t be instantaneous decreased. So, the generator rotor will accelerate unless another control for thee mechanical torque input. In Fig. 6 assumes that, the two sources power system at steady state operation have balance point of δ with transferring electric power P0. At fault condition the power output is reduced to PF, the generator rotor starts to accelerate, but the mechanical input not changed so the δ will be increase. At this time, the fault is clear, the generator angle reaches to δc, because the electric power output PC at the angle δc is larger than the mechanical power input P0 and the generator speed will begin to decreases. However, the inertia of the rotor system will cause the angle δc not to return back immediately to δ. But, the angle continues increase to δF . (Area - 2) is the energy lost at deceleration its equal to the energy gained at acceleration in (area - 1) this is called equal area criterion [8].

6 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Fig. 5 Power angle curve

Fig. 6 Transiently stable system 4.2 Transient unstable power system If δF is smaller than δL , the system is transiently stable as shown in Fig. 5, and the two sources angle difference eventually return back to original balance point δ0 . However, if (area – 2) is smaller than (area -1) the angle δ increase to angle δL . This lead to the electric power output from the generators is lower than the input mechanical power. Therefore, the rotor will accelerate again and δ , it’s will increase beyond recovery. This a transiently unstable condition in the system, as shown in Fig. 7. At condition in the power system, the two equivalent generators rotate at a different speed which leads to unstable in the system. This event is called a loss of synchronism or an OOS condition in power system [16].

7 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Fig. 7 Transiently unstable system 4.3 Analysis of Two Area System Power swings refer to oscillation in active and reactive power flows on a transmission line consequent to a large disturbance like a fault. The oscillation in the apparent power and bus voltages is seen by the relay as an impedance swing on the R – X plane. If the impedance trajectory enters a relay zone and stays there for sufficiently long time, then the relay will issue a trip decision on power swing. Tripping on power swings is not desirable. We now investigate this phenomenon and then discuss remedial measures [10-17]. Let us consider a simple two machines system connected by a transmission line of impedance ZL as shown in Fig. 1 ES and ER are the generator voltages at two ends and we assume that the system is purely reactive. The voltage ES leads ER by an angle  so that power flows from A to B during steady state. The relay under consideration is located at bus A end. The power angle curve is shown in Fig. 6. The system is operating at initial steady operating point A with Pmo as output power and  0 as initial rotor angle. From the power angle curve, initial rotor angle, P   0 = sin −1  m 0  (16)  Pmax  Now, suppose, a self-clearing transient three phase short circuit fault occurs on the line. During the fault, the electrical output power Pe drops to zero. The resulting rotor acceleration advances rotor angle to  1 . After a time interval tcr , corresponding to angle  1 , the fault is cleared and the operating point jumps back to the sinusoidal curve. Rotor angle correspond to this instant is 1. As per equal area criteria, the rotor will swing up to maximum rotor angle  max , satisfying the following condition, Accelerating Area (A1) = Decelerating Area (A2) Rotor angle 1corresponding to fault clearing time tcr can be computed by swing equation [7-25], 2 H d 2 = Pmo − Pe = Pa s dt 2

(16) 8

Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

where H is the equivalent rotor angle inertia. During fault, Pe = 0, hence, 2 H d 2 = Pmo (18) s dt 2 On integrating both the sides with respect to variable t, d s Pmo (19) = (t − t0 ) dt 2H Prior to fault  0 is a stationary point. d The initial condition of is specified as follows dt d =0 dt t =t 0

Integrating equation (19) and substituting  = 1 at time t = t1, with t1 − t 2 = t cr , P 1 = s mo (tcr2 ) +  0 (20) 4H Thus, accelerating area A1 is given by, 1

1 =  Pmo d = Pmo (1 - 0 )

(21)

0

= Pmo (1 −  0 ) Substituting in equation (21),  P 2 (t 2 ) 1 = s mo cr (22) 4H Similarly, decelerating area, A2, can be calculated as follows.

2 =

 max

 1

Pmax Sin .d = Pmax (Cos1 − Cos max ) − Pmo ( max − 1 )

Since for a stable swing, 1 =  2 Pmo = (1 −  0 ) = Pmax (Cos1 − Cos max ) − Pmo ( max − 1 ) i.e. cos max = cos 1 −

Pm 0 ( max −  0 ) Pmax

(23)

(24)

(25)

Since δ0 is function of Pmo from equation (16) and δ1 is function of Pmo as well as t cr from equation (20), it follows from equation (25) that δmax depends on Pmo and tcr. 9 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

i.e.  max = f ( Pm 0 , t cr ) (26) The variation of max verses Pmo for different values of tcr is shown in Fig. 8.

Fig. 8 Plots of max verses Pmo, for different values of tcr 4.4

Determination of power swing locus

A distance relay may classify power swing as a phase fault if impedance trajectory enters the operating characteristic of the relay. We will now derive the apparent impedance seen by the relay R on R-X plane. Again, consider simple two machine system connected by a transmission line of impedance ZL as shown in Fig. 1, where machine B is treated as reference [24-28]. E  − E R I relay = S (27) ZT Where, Z T = Z S + Z L + Z R (28) Now, impedance seen by relay is given by the following equation, Vrelay E S  − I relay Z S Z seen (relay) = = I relay I relay

10 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

     E S   1    Z T = − Z S + Z T = − Z S +  (29)   E E   − E R R   S  −  1− ES   E Let us define k = S . Assuming for simplicity, both the voltages as equal to 1pu, i.e. k=1, ER

 1 Z seen (relay) = − Z S + Z T   1 − cos + j sin 

= −Z S +

ZT 2 sin



(sin





− j cos ) 2 2

2 ZT  = −Z S + (1 − j cot ) 2 2 Z Z  = − Z S + T − j T cot 2 2  2   a cons tan t offset

    ZT  1    = − Z S +   2  2  + j sin cos   sin 2 2 2 

(30)

perpendicular line segment

From equation (30) at  =180 , cot  = 0, Z seen = −Z S +

ZT 2

There is a geometrical interpretation of above equation. The vector component − Z S + (30) is a constant in R – X plane. The component − j

ZT in equation 2

ZT  cot is a straight line, perpendicular to line 2 2

ZT . Thus, the trajectory of the impedance measured by relay during the power swing is a 2 straight line as shown in fig 8. The angle subtended by a point in the locus on S and R end points is angle  . For simplicity, angle of Z S , Z R and Z L are considered identical. It intersects the line AB at mid-point, when  =180 . The corresponding point of intersection of swing impedance trajectory to the impedance line is known as electrical center of the swing in Fig. 8, where, the angle,  between two sources can be mapped graphically as the angle subtended by source points E S and E R on the swing trajectory. At the electrical center, angle between two sources is 180 . The existence of electrical center is an indication of system instability, the two generators now being out of step [25-28]. If the power swing is stable, i.e. if the post fault system is stable, then  max will be less than 180 −  . In such event, the power swing retraces its path at  max . segment

11 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

ES = k  1 , then the power swing locus on the R – X is an arc of the circle. As shown in fig. 9. ER It can be easily shown that ES k (cos + sin  ) k[( k − cos ) − j sin  ] = = (31) E S − E R k (cos + j sin  ) − 1 (k − cos ) 2 + sin 2  Then, k (k − cos ) − j sin   Z seen = − Z S + ZT (k − cos ) 2 + sin 2  If

Fig. 8 Intelligent relay characteristics Impedance trajectories at OOS

12 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Fig. 9 Impedance Trajectories at relay point during power swing

ES ratio. ER Appearance of electrical center on a transmission line is a transient phenomenon. The voltage profile across the transmission at the point of occurrence of electrical center is shown in fig. 9. It is also clear from Fig. 7b, that the location of the electrical center is dependent upon the

At the electrical center, the voltage is exactly zero. This means that relays at both the ends of line perceive it as a bolted three phase fault and immediately trip the line. Thus, we can conclude that existence of electrical center indicates (1) system instability (2) possibility of nuisance tripping of distance relay, as shown in fig. 10. Now consider a double-end-feed transmission line with three stepped distance protection schemes having Z1, Z2 and Z3 protection zones as shown in Fig. 10 and Fig. 11. The mho relays are used and characteristics are plotted on R-X plane as shown in Fig. 11. Swing impedance trajectory is also overlapped on relay characteristics for a simple case of equal end voltages (i.e. k = 1) and it is perpendicular to line AB. T 3Z

T 2Z EA O

T 1Z 1

Revers e fault

Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Forwar d

EB0

2 M

ZL 1

1

3

N

ZL 2

2

3

13

Fig. 10 Single line diagram showing three protection zones

Fig. 11 Three stepped distance protection From Fig. 10 and Fig. 11,  Z 1 ,  Z 2 and  Z 3 are rotor angles when swing just enters the zone Z1, Z2 and Z3 respectively and it can be obtained at the intersection of swing trajectory to the relay characteristics. Recalling δmax is the maximum rotor angle for stable power swing, following inferences can be drawn. If  max   Z 3 , then swing will not enter the relay characteristics. 14 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

If  Z 3   max   Z 2 , swing will enter in zone Z 3 . If it stays in zone - Z 3 for larger interval than its TDS, then the relay will trip the line. If  Z 2   max   Z 1 , swing will enter in both the zones Z 2 and Z 3 . If it stays in zone 2, for larger interval than its TDS, then the relay will trip on Z 2 If  max   Z 1 , swing will enter in the zones Z 1 , Z 2 and Z 3 and operate zone 1 protection will operate without instantaneous delay. Evaluation of power swings on a multimachine system requires usage of transient stability program. Using transient stability program, post fault the relay end node voltage and line currents can be monitored and then the swing trajectory traced on impedance. 4.5 OOS Effect on Distance Function in IEDs OOS can affect the calculations of load impedance in IEDs, where, at steady state conditions is not within the IED operating zone characteristic, to enter the calculations into the IEDs operating zone characteristic as show in Fig. 12 When impedance due to power swing matches with the operating impedance of the distance relay, it will send false tripping to the circuit breaker. During OOS the IEDs may cause undesired tripping of OHTL or other power system elements, by weakening the system and possibly lead to cascading outages and the shutdown of major portions of the power system [20] [26]. Fig. 113 shows the three-phase current and voltage at OOS, so at the point of the voltage is low, the protection relay impedance calculation will sense this point as a fault in the system.

Fig. 12. IEDs operation logic of distance function

Fig. 13. Voltage and current curve forms at OOS 15 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

5. Distance IEDs requirements at OOS OOS functions in IEDs detect stable OOS conditions by using the fact that the voltage and current calculations during a power swing is gradual changing while it is virtually a step change during a fault. Both faults and OOS may cause the measured apparent positive-sequence impedance to enter into the operating characteristic of a distance relay element [5]. In Fig. 14, plot of the current and voltage over the entire 60 second at OOS. Because of the complexity and the rare occurrence of power system at OOS, many of utilities haven’t clear performance that requirement for distance IEDs during OOS [10]. So, the performances of distance elements at OOS conditions must be blocking the distance function in IEDs during stable power swings in the system [21]. But the OST function should be taken into account to accomplish differentiation stable from unstable power swings, and separation to system areas at the predetermined network locations and at the appropriate source-voltage phase-angle difference between systems, in order to maintain power system stability and service continuity [22].

Fig. 14 Voltage and current over the entire 60- second at OOS 5.1 Solution for Distance IEDs at OOS The IEDs design ability to develop and realize new methods for detecting power swings [21]. In Fig. 15 the design for anew zones over from higher actual setting for tripping zones. The advanced protection relay calculates the line impedance that can to indicate to detecting OOS on the power system; these methods depending on measuring apparent impedance and timing between two elements. If the apparent impedance remains between the inner and outer characteristics new zones for the set time delay, this time delay depends on the number of cycles at swing in the system which, the average time between 3 to 5 cycles. After that, the PSB element activate and selected distance element zones for three phase symmetrical fault are blocking from operation to ensure that the generator rotor return to steady state operation. Calculation of the maximum transient time used to adjust the blocking time of the OOS function [24-27]. OST schemes require for tripping scheme to separate the power system at key locations to achieve a new steady-state operating condition [23]. OST scheme uses the same measuring element or a different set of measuring elements depend on the IEDs type. A timer 16 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

determines if the change in impedance is a result of a fault or a power swing. If it is an unstable power swing, then IEDs can select tripping on the way into the characteristic. In some OST applications, the locus of OOS may not be the ideal location for separation generations. So, the system stability studies must be applying to determine the best location for detection of OSB and the best location for the OST for separation [23].

Fig. 15 Design for anew zones for OOS 6. Simulation three phase distance protection function This experiment shows the test for distance protection in IEDs. The test applied by using a secondary injection kit type Freja300.The nominal operating voltage for this system is 132 kV. The voltage transformer ratio is 132/0.115 kV and the current transformer ratio is 1000/1 Amps. Maximum load is 1000 Amps at a ±30-degree power factor. The Zone 1, Zone 2, Zone 3 and distance element reaches are set to be 85 %, 130%, 180% forward direction and Zone 4 adjusted by 30 % reverse of the line impedance, respectively. This three-phase symmetrical fault test simulated by a protection IEDs type SEL411L. Fig. 16 shows the scheme quadrature operation for the test results created by Freja win software. Table (1) and table (2) shows the report for the impedance results at symmetrical fault simulation.

17 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Fig. 16 Actual quadrature three phase distance

Table 1. Test result for three phase fault in all setting zone

NO

R (Ohm)

X (Ohm)

Z (Ohm)

Z phi

Z Tol. (%)

Z diff. (%)

Zones

Pass / Fail

1 2 3 4

3.599 4.748 0 0

0 4.748 12.784 20.979

3.599 6.714 12.784 20.979

0 45 90 90

5% 5% 5% 5%

0.60% 0.7% 0.60% 0.30%

1 1 1 2

Pass Pass Pass Pass

5

0

26.518

26.518

90

5%

0.10%

4

Pass

6

-11.151

13.29

17.349

130

5%

3.30%

1

Pass

7

-4.481

-4.481

6.338

225

5%

0.50%

3

Pass

8 9 10 11 12 13

-6.58 0 6.072 -3.85 -6.285 -7.946

-17.142 -17.238 -17.336 12.915 21.086 26.656

18.362 17.239 18.37 13.477 22.003 27.816

249 270 289.3 106.6 106.6 106.6

5% 5% 5% 5% 5% 5%

0.30% 0.20% 0.70% 0.30% 0.70% 0.60%

3 3 3 1 2 4

Pass Pass Pass Pass Pass Pass 18

Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

14 15 16 17 18 19

5.826 3.042 5.018 6.361 -13.743 -6.77

9.098 12.668 20.899 26.493 6.505 13.062

10.803 13.028 21.492 27.245 15.205 14.712

57.4 76.5 76.5 76.5 154.7 117.4

5% 5% 5% 5% 5% 5%

0.90% 0.10% 0.10% 0.10% 0.40% 0.10%

1 1 2 4 1 1

Pass Pass Pass Pass Pass Pass

Table 2. Test result for three phase fault in all setting zone NO

R (Ohm)

X (Ohm)

Z (Ohm)

Z phi

Z Tol. (%)

Z diff. (%)

Zones

Pass / Fail

20 21 22 23 24 25 26 27 28

-10.962 -13.502 4.595 7.581 -13.705 -13.762 -1.625 -2.662 -3.362

21.148 26.05 12.624 20.827 12.472 8.6 12.869 21.074 26.615

23.821 29.341 13.434 22.164 18.531 16.229 12.972 21.242 26.827

117.4 117.4 70 70 137.7 148 97.2 97.2 97.2

5% 5% 5% 5% 5% 5% 5% 5% 5%

0.00% 0.50% 0.30% 0.20% 0.20% 0.10% 0.10% 0.70% 0.50%

2 4 1 2 4 2 1 2 4

Pass Pass Pass Pass Pass Pass Pass Pass Pass

29 30 31 32 33 34

1.272 2.095 2.65 3.264 -5.587 -3.092

12.74 20.983 26.549 -17.27 -9.677 -17.187

12.803 21.087 26.681 17.576 11.175 17.464

84.3 84.3 84.3 280.7 240 259.8

5% 5% 5% 5% 5% 5%

0.40% 0.30% 0.20% 0.40% 0.10% 0.20%

1 2 4 3 3 3

Pass Pass Pass Pass Pass Pass

7. Simulation new zones for OOS The test applied by using a secondary injection kit type Freja 300, using Freja win software to draw the new quadrature zones, which over from the actual tipping zones. This test applied on IEDs type RED670, this simulation for132 kV OHTL by a maximum load of 1000A. The voltage transformer ratio is 132/0.115 kV and the current transformer ratio is 1000/1A. Fig. 17 and Fig. 18 show the test results which created by the software simulation and table (3) and table (4) include report results.

19 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Table 3. Test result for new inner zone for blocking OOS

NO

R (Ohm)

X (Ohm)

Z (Ohm)

Z phi

Z Tol. (%)

Z diff. (%)

Zones

Pass / Fail

1 2 3

31.343 0.000 -23.020

86.115 86.138 -85.915

91.641 86.138 88.946

70.0 90.0 105.0

5% 5% 5%

0.5 % 0.5 % 0.3 %

1 1 1

Pass Pass Pass

4 5 6 7 8

31.637 0.000 26.177 -28.990 -26.238

-37.703 -85.883 31.195 32.969 -39.833

49.219 85.884 40.723 43.901 47.698

230.0 270.0 310.0 48.7 123.4

5% 5% 5% 5% 5%

0.6 % 0.2 % 0.1 % 0.8 % 0.2 %

1 1 1 1 1

Pass Pass Pass Pass Pass

9 10 11 12

30.517 -23.001 25.832 25.976

-86.047 85.839 0.000 0.000

91.300 88.868 25.833 25.976

250.5 285.0 180.0 0.000

5% 5% 5% 5%

0.4 % 0.2 % 0.4 % 0.2 %

1 1 1 1

Pass Pass Pass Pass

Table 4. Test result

for new outer zone for blocking OOS

NO

R (Ohm)

X (Ohm)

Z (Ohm)

Z phi

Z Tol. (%)

Z diff. (%)

Zones

Pass / Fail

1 2

33.802 0.000

92.869 92.540

98.829 92.540

70.0 90.0

5% 5%

0.7 % 0.4 %

2 2

Pass Pass

3

-24.750

-92.370

95.628

105.0

5%

0.2 %

2

Pass

4

39.019

-46.501

60.704

230.0

5%

0.5 %

2

Pass

5

0.000

-92.597

92.598

270.0

5%

0.5 %

2

Pass

6 7 8

32.579 -36.002 -32.759

38.825 40.944 -49.733

50.684 54.521 59.553

310.0 48.7 123.4

5% 5% 5%

0.1 % 0.7 % 0.3 %

2 2 2

Pass Pass Pass

9

32.801

-92.488

98.133

250.5

5%

0.4 %

2

Pass

10 11 12

24.805 -33.004 32.621

92.571 0.000 0.000

95.838 33.004 32.622

285.0 0.0 180.0

5% 5% 5%

0.5 % 0.4 % 0.1 %

2 2 2

Pass Pass Pass 20

Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

Fig. 17 Graph result for test the new inner zone

Fig. 18 Graph result for test the new outer Zone 8. Conclusion Stable and unstable out-of-step (OOS) can precipitate widespread outages to power systems with the result that lead to tripping of the power system elements. This paper introduces an overview of OOS, their causes, and optimum method for detecting the OOS. The detecting method for OOS in the system have been developed and elaborated. The OOS detection logic in the electrical system distinguishes between stable power swings where the system recovers and an unstable OOS condition where the grid needs to be separated. This paper shows detecting OOS, by creating new boundary two zones over from greater tipping zone, as detecting the load symmetrical impedance between new zones for 21 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

a few cycles. This will lead to blocking for the symmetrical calculating zones by the time for the stable swing in the grid which will prevent from separating grid or system black out. References

[1] Pituk Bunnoon “Fault Detection Approaches to Power System: State-of-the-Art Article Reviews for Searching a New Approach in the Future” - International Journal of Electrical and Computer Engineering (IJECE) - 2013, pp. 553~560 - ISSN: 2088-8708. [2] Tolu.O. Akinbulire, Peter.O. Oluseyi and Chris.I.Esumeh “ Optimal Relay Performance Using Advanced Fault Diagnostic Techniques” Department of Electrical/ Electronic Engineering University of Lagos, Akoka, Yaba, Lagos, Nigeria. [3] Power Swing and Out-Of-Step Consideration on Transmission Lines - Report to the Power System Relaying Committee of the IEEE Power Engineering Society” [4] Ahad Esmaeilian and Mladen Kezunovic “Evaluation of Fault Analysis Tool under Power Swing and Out-ofStep Conditions” ARPA-E to develop RATC solution under GENI contract 0473-1510. [5] Demetrios A. Tziouvaras and Daqing Hou - Out-of-Step Protection Fundamentals and Advancements [6] Walter A. Elmore” protective relaying theory and applications “second edition revised and expanded. [7] Joe Mooney, P.E. and Normann Fischer “Application Guidelines for Power Swing Detection on Transmission Systems”-2006, 42nd Annual Minnesota Power Systems Conference Saint Paul, Minnesota November 7– 9. [8] ABB - Protection Application Handbook, BA THS/BU Transmission Systems and Substations ABB Transmission and Distribution Management Ltd book no (6). [9] E. F, Vaage “A solution for faults at two locations in three-phase power systems” IEEE 2014, ISSN: 0005-8580, pp:290-305. [10] A.P.Vaidya and Prasad A. Venikar” Distance Protection Scheme For Protection of Long Transmission Line Considering the Effect of Fault Resistance By Using the ANN Approach” International Journal of Electrical and Electronics Engineering 2012 (IJEEE) ISSN (PRINT): 2231 – 5284, Vol-1, Iss-3. [11] S. Paudyal and R. Gokaraju “Out-of-step protection for multi-machine power systems using local measurements “IEEE- 2015, ISBN: 978-1-4799-7692-8. [12] Fang SHI “Out-of-step Prediction for Power System Using Improved Prony Algorithm “2016, MATEC Web of Conferences70, 10012, ICMIT. [13] Erik Ela, Michael Milligan, and Brendan Kirby “Operating Reserves and Variable Generation” BOOK -2011; Technical Report NREL/TP-5500-51978. [14] Ali M. Eltamaly, Amer Nasr A. Elghaffar. (2017). A Survey: HVDC System Operation and Fault Analysis. Annals Engineering Jounal ISSN: 1584-2665, Vol.4. [15] Liansong Xiong, Fang Zhuo and Feng Wang “Static Synchronous Generator Model: A New Perspective to Investigate Dynamic Characteristics and Stability Issues of Grid-Tied PWM Inverter” 2015, PP: 6264 – 6280; Print ISSN: 0885-8993. [16] Ramon Sandoval, Armando Guzman and Hector J. Altuve “Dynamic simulations help improve generator protection “; ISBN: 978-1-4244-0854-2, IEEE- 2009. [17] V. Anantha Lakshmi and T. R. Jyothsna “Mitigation of voltage and current variations due to three phase fault in a single machine system using distributed power flow controller “, IEEE-2016, ISBN: 978-1-4673-9939-5. [18] Damien Tholomier, Simon Richards and Alexander Apostolov “Advanced distance protection applications fot dynamic loading and out-of step condition", IEEE-2007, ISBN: 978-1-4244-1518-2. [19] X. G. Magagula, D. V. Nicolae and A. A. Yusuff “The performance of distance protection relay on series compensated line under fault conditions“ IEEE- 2015,ISSN: 2153-0033. [20] Prashant Gawande, Pallavi Bedekar and Milind Bagewadi “An adaptive distance relay protection scheme for enhanced protection security” IEEE- 2016; ISBN: 978-1-5090-0128-6. [21] Don Kang and Ramakrishna Gokaraju “A New Method for Blocking Third-Zone Distance Relays During Stable Power Swings “, IEEE Transactions on Power Delivery (Issue: 4, Aug. 2016), IEEE-2016, ISSN: 0885-8977. 22 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com

[22] Mojdeh Abdi-Khorsand and Vijay Vittal “Modeling Protection Systems in Time-Domain Simulations: A New Method to Detect Mis-operating Relays for Unstable Power Swings” IEEE Transactions on Power Systems (Volume: PP, Issue: 99); IEEE-2016, ISSN: 0885-8950. [23] Prashant N Gawande and Sanjay S Dambhare “A novel unblocking function for distance relay to detect symmetrical faults during power swing “Power and Energy Society General Meeting (PESGM) , IEEE-2016, ISSN: 1944-9933. [24] S. Gautam and S.M. Brahma “ Out-of-step blocking function in distance relay using mathematical morphology” IET Generation, Transmission & Distribution; IEEE-2012, ISSN: 1751-8687. [25] Swati A. Lavand and S. A. Soman“Predictive Analytic to Supervise Zone 1 of Distance Relay Using Synchrophasors “IEEE Transactions on Power Delivery; IEEE-2016, ISSN: 0885-8977. [26] Vinaya A. Ambekar and Sanjay S. Dambhare “Comparative evaluation of out of step detection schemes for distance relays” Power India Conference, IEEE Fifth, 2012, ISBN: 978-1-4673-0766-6. [27] Ali M. Eltamaly and Amer Nasr Abd Elghaffar “Modeling of distance protection logic for out of step condition in power system” Electrical Engineering journal, 201, doi.org/10.1007/s00202-017-0667-3. [28] Jorge Santam. (2011). Analysis of power systems under fault conditions. master of science, in electrical and electronic engineering at california state university, sacramento [29] Anubha Gupta, Sunil V Chandran and S. S. Bhat. (2014). Simultaneous fault analysis. International Conference on Power, Automation and Communication (INPAC), India, ISBN: 978-1-4799-7169-5, DOI: 10.1109/INPAC.2014.6981131.

The Acknowledgment • This research was supported by a grant(18AUDP-B099686-04) from Architecture & Urban Development Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government. • The authors would thanks to Prof. Dr. Husam A. Ramadan and Prof. Dr. Mohamed M. A. Elaziz, Electrical Engineering Department, Minia University, Egypt. for supporting this research.

Authors Biographies Ali M. Eltamaly: was born in Egypt, in 1969. He received his B.S. M.Sc. and PhD, in 1992, 1996, and 2000, respectively. He was a faculty member in the College of Engineering, Minia and Mansoura universities, Egypt, from 1993 to 2005. He joined Electrical Engineering Department, and Sustainable Energy Technologies Center, King Saud University, Saudi Arabia since from 2005 till now. His current research interests include renewable energy, power electronics, motor drives, power quality, and smart control. He has invented number of patents and has supervised a number of M.Sc. and PhD theses, supervised and participated on number of technical national and international projects, published Four books, many book chapters and more than 100 papers. Amer Nasr A. Elghaffar was born in Minia, Egypt on 1987. He received B.Sc., M.Sc. degree in electrical engineering from Minia University, Egypt followed with Power and Machine in 2009; and 2016. He is a researcher in Electrical Engineering, Minia University, Egypt. His current research interests include protection and control system, power quality, HVDC and high voltage.

23 Company Registration No.: 201120424K 21 Serangoon North Avenue 5, #03-03, Ban Teck Han Building, Singapore (554864) www.PiscoMed.com