JOY

JOY JOY IS A NOUN REJOICE IS A VERB WHEN YOU REJOICE, YOU HAVE JOY IN YOUR HEART WHEN YOU REJOICE YOU ARE JOYFUL. QUESTIONS: - WHAT BRINGS ABOUT JOY? - WHAT MAKES YOU TO REJOICE? LIKE MOST THINGS WE DO, WE NEED CAPACITY AND ABILITY TO REJOICE. NOTICE THAT IN THE BIBLE, WHEN PEOPLE SINCERELY HAVE AN ENCOUNTER WITH JESUS CHRISTFOR THE RIGHT REASONS AND WITH THE RIGHT MOTIVES AND THEY ACCEPT HIM(JESUS CHRIST) AND OBEY HIM (JESUS CHRIST) AND CARRY OUT HIS DIRECTIVES AND INSTRUCTIONS, MAKING HIM LORD AND SAVIOUR, THEY GO ABOUT REJOICING . WHEN THE REVERSE IS THE CASE, THEY GO AWAY SOROWING. JUST AS THE REACH MAN WHO WAS ASKED TO SELL WHAT HE HAD AND GIVE TO THE POOR AND FOLLOW JESUS CHRIST. MT.19:22, LK18:23 THIS SHOWS THAT CONTACT WITH JESUS CHRIST BRINGS JOY. JESUS CHRIST TAKES AWAY OUR SINS AND LEAVES US REJOICING EVERMORE. REPENTANCE BRINGS JOY FORGIVENESS BRINGS JOY THE JOY OF THE LORD IS OUR STRENGTH THE WORD OF THE LORD BRINGS JOY AN ENCOUNTER WITH GOD BRINGS JOY OBEDIENCE BRINGS JOY SALVATION BRINGS JOY. Jn 14:28 If you love me ye would rejoice. The sincere love of and for our Lord Jesus Christ will make you to rejoice. If you are not rejoicing, ask yourself why? Ask yourself about your sincere love for our lord Jesus Christ. Jesus Christ in you will bring joy to you. Let us believe in our lord Jesus Christ today for our salvation and He will keep us rejoicing for evermore and give us an everlasting joy.

JOY

JOY JOY IS A NOUN REJOICE IS A VERB WHEN YOU REJOICE, YOU HAVE JOY IN YOUR HEART WHEN YOU REJOICE YOU ARE JOYFUL. QUESTIONS: - WHAT BRINGS ABOUT JOY? - WHAT MAKES YOU TO REJOICE? LIKE MOST THINGS WE DO, WE NEED CAPACITY AND ABILITY TO REJOICE. NOTICE THAT IN THE BIBLE, WHEN PEOPLE SINCERELY HAVE AN ENCOUNTER WITH JESUS CHRISTFOR THE RIGHT REASONS AND WITH THE RIGHT MOTIVES AND THEY ACCEPT HIM(JESUS CHRIST) AND OBEY HIM (JESUS CHRIST) AND CARRY OUT HIS DIRECTIVES AND INSTRUCTIONS, MAKING HIM LORD AND SAVIOUR, THEY GO ABOUT REJOICING . WHEN THE REVERSE IS THE CASE, THEY GO AWAY SOROWING. JUST AS THE REACH MAN WHO WAS ASKED TO SELL WHAT HE HAD AND GIVE TO THE POOR AND FOLLOW JESUS CHRIST. MT.19:22, LK18:23 THIS SHOWS THAT CONTACT WITH JESUS CHRIST BRINGS JOY. JESUS CHRIST TAKES AWAY OUR SINS AND LEAVES US REJOICING EVERMORE. REPENTANCE BRINGS JOY FORGIVENESS BRINGS JOY THE JOY OF THE LORD IS OUR STRENGTH THE WORD OF THE LORD BRINGS JOY AN ENCOUNTER WITH GOD BRINGS JOY OBEDIENCE BRINGS JOY SALVATION BRINGS JOY. Jn 14:28 If you love me ye would rejoice. The sincere love of and for our Lord Jesus Christ will make you to rejoice. If you are not rejoicing, ask yourself why? Ask yourself about your sincere love for our lord Jesus Christ. Jesus Christ in you will bring joy to you. Let us believe in our lord Jesus Christ today for our salvation and He will keep us rejoicing for evermore and give us an everlasting joy.

JOY

JOY JOY IS A NOUN REJOICE IS A VERB WHEN YOU REJOICE, YOU HAVE JOY IN YOUR HEART WHEN YOU REJOICE YOU ARE JOYFUL. QUESTIONS: - WHAT BRINGS ABOUT JOY? - WHAT MAKES YOU TO REJOICE? LIKE MOST THINGS WE DO, WE NEED CAPACITY AND ABILITY TO REJOICE. NOTICE THAT IN THE BIBLE, WHEN PEOPLE SINCERELY HAVE AN ENCOUNTER WITH JESUS CHRISTFOR THE RIGHT REASONS AND WITH THE RIGHT MOTIVES AND THEY ACCEPT HIM(JESUS CHRIST) AND OBEY HIM (JESUS CHRIST) AND CARRY OUT HIS DIRECTIVES AND INSTRUCTIONS, MAKING HIM LORD AND SAVIOUR, THEY GO ABOUT REJOICING . WHEN THE REVERSE IS THE CASE, THEY GO AWAY SOROWING. JUST AS THE REACH MAN WHO WAS ASKED TO SELL WHAT HE HAD AND GIVE TO THE POOR AND FOLLOW JESUS CHRIST. MT.19:22, LK18:23 THIS SHOWS THAT CONTACT WITH JESUS CHRIST BRINGS JOY. JESUS CHRIST TAKES AWAY OUR SINS AND LEAVES US REJOICING EVERMORE. REPENTANCE BRINGS JOY FORGIVENESS BRINGS JOY THE JOY OF THE LORD IS OUR STRENGTH THE WORD OF THE LORD BRINGS JOY AN ENCOUNTER WITH GOD BRINGS JOY OBEDIENCE BRINGS JOY SALVATION BRINGS JOY. Jn 14:28 If you love me ye would rejoice. The sincere love of and for our Lord Jesus Christ will make you to rejoice. If you are not rejoicing, ask yourself why? Ask yourself about your sincere love for our lord Jesus Christ. Jesus Christ in you will bring joy to you. Let us believe in our lord Jesus Christ today for our salvation and He will keep us rejoicing for evermore and give us an everlasting joy.

PROTECTION

PROTECTION ZONE OF PROTECTION The idea of an area of responsibility of a protection system mentioned above has been formalized by assigning zones of protection to various protection systems. This concept of zones help to define the reliability requirements for different protection systems. Each breaker is included in two neighbouring zones of protection. The boundry of each zone defines a portion of the power system such that for a fault anywhere within that zone, the protection system responsible for that zone takes action to isolate everything within that zone from the rest of the system. The CB. Circuit Breaker help to define the boundries of the zones of protection. This is because at each point where connection is made b/w equipment inside the zone and the rest of the power system, a CB. Is or should be inserted because isolation under faulted condition is achieved through a CB. Neighbouring zones always overlap. This is important so that small parts of the system do not get left out without protection. The region of overlap is however made as small as possible to reduce very large disruptions to the system.

ELECTRICAL POWER SYSTEM PROTECTION

ELECTRICAL POWER SYSTEM PROTECTION ELECTRICAL POWER SYSTEM PROTECTION IS VERY IMPORTANT TO SAFEGAURD LIFE AND PROPERTY ELECTRICAL POWER SYSTEM INSTALLATIONS ARE VERY EXPENSIVE AND SHOULD BE PROTECTED IN THE EVENT OF A FAULT A PROTECTION SCHEME WOULD HAVE - A TRANSDUCER - A RELAY - A CIRCUIT BREAKER CIRCUIT BREAKING PROCESS WHEN THE TRIP CIRCUIT OF A CIRCUIT BREAKER IS ENERGIZED BY THE RELAY, THE CONTACTS OF THE CIRCUIT BREAKER WHICH IS IN SERIES WITH THE TRANSMISSION LINE BEGIN TO MOVE APART VERY RAPIDLY. AS THE CURRENT THROUGH THE BREAKER CONTACTS (IE. THE FAULT CURRENT) PASSES THROUGH ZERO. THE SPACE B/W THE CONTACTS BECOME A DIELECTRIC AND IS ABLE TO PREVENT THE FAULT CURRENT FROM FLOWING AGAIN THROUGH THE CIRCUIT BREAKER. THIS TAKES BETWEEN 30 – 100 MILISECONDS THERE ARE FASTER SYSTEMS IN PLACE NOW. CONSIDER THE RELAY R23 OF LINE 2-3 AT TERMINAL 2. THE CURRENT AND VOLTAGE INPUT TO IT CHANGE DUE TO FAULT AT P IE. R23 ALSO SEES THE FAULT. HOWEVER, R23 MUST BE SELECTIVE SO THAT IT DOES NOT OPERATE FOR FAULT AT P, IF P IS OUTSIDE THE REACH OF THIS RELAY. REACH – THIS IS THE AREA OF RESPONSIBILITY OF A RELAY THOUGH IT SEES IT (IE THE FAULT) IE. CAUSES SOME CHANGES IN CURRENT AND VOLTAGE INPUT TO THE RELAY. RELAY RELAY CHARACTERISTICS FAST RELIABLE A GOOD RELAY MUST BE FAST AND RELIABLE. Fast RELIABLE (DEPENDABLE AND SELECTIVE) RELIABLE DEPENDABLE SELECTIVE THIS MEANS THAT WHEN THERE IS A FAULT, IT SHOULD OPERATE. AGAIN ON THE OTHER HAND, WHEN THERE IS NO FAULT, IT SHOULD NOT. THIS MEANS THAT THE SMALLEST POSSIBLE PORTION OF THE SYSTEM SHOULD BE ISOLATED; FOLLOWING A FAULT. SPEED AND RELIABILITY CONFLICT THERE SHOULD BE A COMPROMISE KEEP A REASONABLE MEASURE OF THESE TWO WHY DO WE HAVE TO PROTECT THE ELECTRICAL POWER SYSTEM? WHAT ARE THE CONSEQUENCIES OF FAULTS? FAULTS AND SHORT CIRCUITS CAUSE 1) REDUCTION IN STABILITY MARGINS FOR THE POWER SYSTEM 2) DAMAGE TO EQUIPMENT. 3) EXPLOSIONS IN OIL USED FOR INSULATION. 4) DISRUPTIONS IN THE ENTIRE POWER SYSTEM DUE TO SUCCESSION OF PROTECTIVE ACTIONS BY DIFFERENT PROTECTIVE SYSTEMS. (CASCADING) IN THE PROTECTION OF THE ELECTRICAL POWER SYSTEM, SPEED IS IMPORTANT SPEED IS IMPORTANT. 1 CIRCUIT BREAKER – PROVIDES THE INPUT TO THE RELAY (T) 2 TRANSDUCER – PROVIDE THE INPUT TO THE RELAY (T) 3 RELAY – DEVICES WHICH SENSE THE FAULT AND CAUSE THE CIRCUIT-BREAKER TRIP CIRCUIT S TO BE ENERGIZED AND THE BREAKERS TO OPEN THEIR CONTACTS (R) NOTATION LINE 1-2 HAS BREAKER B12 AT END 1, OR A, B AT FAULT (CONDITIONS) (THERE IS) INCREASED CURRENT FLOW TOWARDS THE FAULT POINT. ( ASSUME SOURCE POWER BEYOND THE ENDS OF THE BUSES. WHEN THIS IS NOT THE CASE, THE ANALYSIS IS SIMPLER) INCREASE IN CURRENT AT LINE TERMINAL IS ACCOMPANIED BY REDUCTION IN VOLTAGE. kA, kV THE FAULT CURRENTS AND VOLTAGES ARE IN kA AND kV HENCE TRANSDUCERS ARE USED TO REDUCE THESE QUANTITIES TO TENS AND SMALLER VALUES FOR RELAYING PURPOSES IN THE PROTECTION SCHEME. HENCE TRANSDUCERS REDUCE THESE TO TENS. THE RELAY TAKES THIS REDUCED SIGNAL, DETERMINE IF A FAULT HAS OCCURRED AND RESPONDS ACCORDINGLY. WITHIN 8 – 40 MILLISECONDS OR LESS (FOR MORE MODERN SYSTEMS) DEPENDING ON DESIGN AND THE MAGNITUDE OF THE FAULT CURRENT. IF THE RELAY DECIDES THAT IT IS A FAULT, THEN IT WILL TRIP THE CIRCUIT BREAKER. SIGNALS CAN BE SENT USING ANY OF THE FOLLOWING MEDIA FOR PROTECTION PURPOSES: TELEPHONE CIRCUIT HIGH FREQUENCY SIGNALS ON POWER LINES POWER LINE CARRIERS MICROWAVE CHANNEL PROTECTION ZONE OF PROTECTION

MORE INFORMATION ON ELECTROMAGNETIC FIELDS AND WAVES

The Battery must do work to keep the potential difference b/w the terminals constant when a current flows in a wire joining the terminals. The work done moving a charge q from A to B terminals is Vq = q ∫ABE.dl Vq = ∫ABF.dl Where F is the force on the charge q (the electron) V = 1/q∫ABF.dl This also represents the e.m.f. of the battery With A and B as terminals. Note that an e.m.f. can exist in a closed circuit (loop) as well as across the terminals of a battery. Whenever the magnetic flux through a closed circuit is changing, the line integral of the force on a charge, integrated around the whole circuit is not zero. In this case, work must be done to take a charge around the circuit, and the work done may be used to define an e.m.f. just as the e.m.f. of the battery explained earlier on. The e.m.f., V around the circuit is given by V = 1/q∮ABF.dl If the closed circuit consists of a conductor of resistance R and contains no other source of e.m.f., other than the one due to changing magnetic fields, then a current I = V/R will flow around the circuit. Motional electromotive force Consider a situation in which an e.m.f. exists in a simple closed circuit. Let us consider its value A metal rod moving with velocity v perpendicular to a uniform field B In the diagram, let us consider a metal rod moving with constant velocity v in a direction perpendicular to a uniform magnetic field B The motion of a charged particle eg an electron in a magnetic field is due to the force it experiences This is given by F = qv^B Magnetic forces always act perpendicularly to the direction of motion of the charged particles. The magnitude of the force is found to be proportional to the speed of the particle, its charge q, and to the sine of the angle between the vectors V and B hence F ∝ qv ^ B The unit of the magnetic field B are defined by choosing the constant of proportionality to be unity. F = qv ^ B This is the Lorentz force law The Lorentz force law has components. F = Fx + Fy + Fz Fx = q(VyBz - VzBy) Fy = q(VzBx - VxBz) Fz = q(VxBy - VyBx) As well as the forces exerted on charges by electric fields, there may be additional magnetic forces experienced by moving charged particles. If an electric field E is present as well as a magnetic field B, a charge q experiences an additional force qE and the total force is, F = qE + qv ^ B This equation defines the fields E and B in free space, where the force on a moving test charge can be measured. Note that the test charge must be small enough not to affect the charge and current distribution s that give rise to the fields, otherwise the measured force will not give those fields present without the test charge. {v ≡ is velocity} Back to Motional ElectroMotiveForce. The magnetic force given by F = qv ^ B This magnetic force on each electron and positive charge in the rod will cause the free electrons in the rod to move towards end a and collect there. F ∝ qv ^ B This gives rise to a charge distribution which produces an electric field which halts further migration of free electrons. The electric field set up produces a force –eE on the electrons exactly equal and opposite to the force -eV ^ B (ie qv ^ B ⇨ the charge q ≡ -e) Which acts on them because of their motion in the magnetic field. Hence -eE = ev ^ B Hence the electric field is E = -v ^ B The potential difference Vab between the ends of the rod and b is given by Vba = ∫baE.dl Hence Vab = vBL Where L is the length of the rod. When you integrate from a to b with respect to .dl you get the length L. Ie Vba = ∫baE.dl = ∫ba-v^B.dl = ∫ba-vxB.dl = ∫ba-|v|B||sinθ.dl = vBL Hence Vab = vBL Where L is the length of the rod. EXAMPLE AN AEROPLANE WITH A WING SPAN OF 50m FLYING HORIZONTALLY AT 800Km PER HOUR AT A PLACE WHERE VERTICAL COMPONENT OF THE EARTH’S MAGNETIC FIELD IS 2x 10-5 T (TESLA) USING EQN BELOW Vba = Vbl There is a voltage difference between thw wing tips Equals 0.22 volts. In the illustration using the metal rod, there is a potential difference between the ends of th rod but no current flow is produced. This is because this constitutes an open circuit. If a metal rod moves on stationary conducting rails, perpendicularly to a uniform magnetic field, a current will flow because a complete circuit has been formed. A metal rod moving with velocity v on stationary conducting rails. A uniform field B acts as shown. In this case, charge do not build up on the ends a and b rather electrons traverse the complete circuit from b to a and around to b again; and continues to circulate. The line integral of the force on a charge q evaluated around the complete circuit is given by ∮F.dl = qvBL L is the length of the rod. NB: Note that only rod ab is in motion with velocity v. Hence only charges or electrons on the rod ab are moving with v velocity. The sole contribution to the line integral comes from the portion ab of the loop. The e.m.f. in the closed circuit is given by 1/q∮F.dl = vBL This can be called a motional e.m.f. because it is produced by the motion of a conductor in a magnetic field. The motional e.m.f. causes a current I to flow given by I = (vBL)/R Where R is the resistance of the circuit. Power is given by I2R Therefore, The instantaneous Power is given by (vBL)2/R The work is derived from the mechanical force needed to move the rod along the rails. WE CAN EXTEND THIS CONCEPT A BIT FURTHER TO DEVELOP AN ALTERNATING CURRENT OR E.M.F. USING THE SAME PRINCIPLE. In this case, instead of a rod, we shall consider a rectangular circuit moving with constant speed v through a region of uniform magnetic field. Consider the diagram below. At first only the portion ab is within the field. This means that induced e.m.f. will cause current to flow as the electrons will migrate towards a from d round the circuit and back to b again. This will reperesent current flow in one direction. So long as this part of the conductor is the only part of the conductor at right angle to the direction of motion of the conductor v, it will be the only contributor to this emf and hence the current flow. Since sin (90)=1 and sin(0) = 0 The situation changes when the entire rectangular circuit is in the magnetic field. At this stage, the end cd comes into the picture. Again electrons migrate towards d from c as a result of the Lorentz force experienced by the charged particles, in this case, the free electrons. These electrons move from c to d and back to c again. Notice that this direction is opposite the direction of the electron motion described earlier on when only ab part of the rectangular circuit was in the magnetic field. The result of this is that the two effects will cancel out the the resulting electromagnetic force will be zero as well as the current flow. That is the current flow will also be zero. (Note that we assume all things being equal. Ie that the magnetic field is uniform everywhere withing the magnetic region and that the rectangular circuit is regular uniform and made of homogenous material. Ie the ends ba and cd are identical.) When the rectangular circuit moves so that the end ba is now outside the magnetic region or field, its effect ceases to be felt. We are now left with only the effect of the end cd which causes the electrons to migrate from c to d and back to c again. This brings about a current flow in a direction opposite the current flow we experienced at the beginning of the experiment. SUMMARY WHEN THE COIL IS ENTERING THE FIELD, THERE IS AN EMF OF MMAGNITUDE vBL IN THE CIRCUIT AND THIS PRODUCES A CURRENT AS SHOWN IN THE DIAGRAM WHENHEN THE WHOLE COIL IS MOVING WITHIN THE UNIFORM FIELD, THE E.M.F. AND CURRENT ARE ZERO. THIS IS BECAUSE THE MAGNETIC FORCES ALONG THE SIDES ab AND cd CANCEL EACH OTHER OUT. WHEN THE COIL LEAVES THE FIELD THERE IS AGAIN AN E.M.F. EQUAL TO vBL BUT IT NOW ACTS IN THE OPPOSITE DIRECTION. The diagram above shows the variation of current with time for the moving circuit shown in the figure earlier on. (the rectangular circuit) The current is not exactly as shown; it cannot rise and fall infinitely quickly. The e.m.f. in the coil as it enters or leaves the field can be expressed in terms of the total magnetic flux through the coil. This flux is the sum of the part BLx [B- flux density, Lx – cross sectional area] due to the external field, where x is the length of the coil in the field, and the part due to the induced current in the coil itself. Since the induced current and the area of the coil are constant, this later contribution to the magnetic flux is constant. And 𝜕Φ/𝜕t = BL𝜕x/𝜕t = BLv The magnitude of the emfis given by |e.m.f.| = 𝜕Φ/𝜕t H-magnetic field strength H- magnetic field intensity B=𝜇H B = 𝝻H B – magnetic field density B – Magnetic flux density B = 𝝻𝝻0H = 𝜇𝜇0H 𝝻 = 𝜇 = RELATIVE PERMEABILITY 𝜇0 = 𝝻0 = PERMEABILITY IN FREE SPACE OR IN A VACUUM RETARDED POTENTIALS

JESUS CHRIST IS LORD

THE LORD IS MY STRENGTH AND MY SALVATION THE LORD IS MY STRENGTH AND MY SHIELD