This model demonstrates how a block of rock is extended by a normal fault. Cut the fault model making sure to include the tabs. In a ground fault or earth fault, current flows into the earth. Earthquakes and volcanoes 1 sciencematters a model of plate faults lesson concept movement at plate boundaries produces different types of faults. Glue the fault model to the piece of construction paper and once again cut it out making sure to leave the tabs attached. This model must account for all thermal processes in the motor while motor is starting, running at normal load, running overloaded and if motor is stopped.
After you make the fault model from directions above, illustrate a normal fault. This box is a three dimensional model of the top layers of the earths. The notion that major, throughgoing normal faults can rapidly form was first fully discussed in the seminal paper by cowie 1998. The maximum temperature for the metallic screenarmour is normally the maximum shortcircuit. By convention, the faulted phases are selected for fault symmetry with respect to reference phase a. The three fundamental fault types are normal, reverse, and strikeslip figure 1.
It also represents the extensional motion and resultant rift development associated with divergent plate boundaries table 1. Modeling earth faults in a power transformer and restricted. The primary protective element of the motor protection relay is the thermal overload element and this is accomplished through motor thermal image modeling. In the event of an earth fault in a 230400 v tn system, an exposed part will have a 230 v voltage to earth unless it has an earth connection. Four sampled faults yield distinguishable types of growth. Fold each side of the fault model down to form a box with the drawn features on the top. As the area is stretched, the rocks move along the fault. Gavin hayes these are events along with events from dr. Reverse faults indicate compressive shortening of the crust. Compared to a simple planar model, such a fault accommodates a considerably greater amount of extension for. Link forces in the earth tension, compression, shearing from lesson 6. I just needed a quick list to reference and figure i might as well share with. If we model the utility system with identical values for all the sequence. The directionality of the earth fault elements is provided by either residual voltageor negative sequence voltage.
They are intended as a complement to structural geology coursework on faults and to related mapwork. The first two models represent recent fault movement with no erosion. Earthprints is an open archive created and maintained by istituto nazionale di geofisica e vulcanologia. Normal fault earthquakes or graviquakes scientific reports. An opencircuit fault occurs if a circuit is interrupted by some failure. Line to ground fault occurs most commonly in overhead line. What is the difference between earth fault and ground. Being rather dominated by gravity, it could be defined as a graviquake fig. The next paragraph presents a simulation model and describes relations important. This box is a three dimensional model of the top layers of the earth s crust.
In this paper the normal condition of threephase transformer model and the internal fault are presented by emtp software for 230kv63kv power transformer, at last by simulation of restricted earth. Earth fault currents in three phase systems diva portal. Standard andersonbyerlee fault mechanics predicts that it is easier to form or reactivate a normal fault in the dip range 3060 than reactivate an existing lanf anderson, 1942. For solidly grounded systems a restricted earth fault protection is typically provided as an addition to the normal transformer differential relay. Single phase earth faults in high impedance grounded networks.
The simplest model of a normal fault is a planar fault that does not change its dip with depth. Detection and location of earth fault in mv feeders using. In this paper the normal condition of threephase transformer model and the internal fault are presented by emtp software for 230kv63kv power transformer, at. In threephase systems, a fault may involve one or more phases and ground, or may occur only between phases.
System at load end in this case is disconnected form source in. Usgs finite fault models university of southern california. Vertical fault movement changes the elevation of a rock mass on one side of the fault relative to the rock mass on the opposite side. Standard andersonbyerlee fault mechanics predicts that it is easier to form or reactivate a normal fault in the dip range 3060 than reactivate an. If fault f2 dominates f1, then f2 is removed from the fault list. Follow the directions for making your fault block model. For placement of sensors please refer to the relay manual. On the relay side of the vt, the third harmonic voltage will be. In reference 8, there is a model deduced for phase earthing situation by means of the. Martin mais srcmod database that i am currently using in my research. Paste or glue the fault model onto a piece of construction paper. For full details of the highset instantaneous units refer to relevant publications. Normal faults are common in regions of crustal extension. Groundfault circuit interrupters personnel protection.
A fault model identifies targets for testing model faults most likely to occur fault model limits the scope of test generation create tests only for the modeled faults a fault model makes analysis possible associate specific defects with specific test patterns effectiveness measurable by experiments. Normal fault model earth and space science, science. This model is consistent with earthquakes along intraplate rifts, but it may not entirely apply to normal fault earthquakes generated as aftershocks of thrust faults along the bending of a subducting lower plate or in the hangingwall of a megathrust such as the outer trenchslope faulting associated to the event of 2011 mw 9. A model of plate faults lesson concept movement at plate boundaries produces different types of faults. In an electric power system, a fault or fault current is any abnormal electric current. Tleis bsc, msc, phd, ceng, fiee, in power systems modelling and fault analysis, 2008. Normal faults form when the hanging wall drops down in relation to the footwall. A similar, rapidestablishment theme is characteristic of the constantlength fault model fig. Response of unconfined turbidity current to normal. A normal fault is one in which an upper block of rock, separated by a fault from a lower block, moves downward relative to the lower block.
Department of the interior how to construct seven paper. Print or photocopy the model on heavy photocopy paper no heavier than about 160gsqm, cut it out and fold it. Color the fault model that is included according to the color key provided. In case of an earth fault occurring across one of the phases the neutraltoground voltage becomes equal to the voltage across the faulted phase and also the sum of currents passing through the healthy phases is equal to the current flowing through the faulted phase. Ground fault current distribution when a ground fault occurs. Digital testing 5 common fault models single stucksingle stuckat faultsat faults transistor open and short faults memory faults pla faults stuckpla faults stuckat, crossat, crossat, crosspoint, bridgingpoint, bridging functional faults processors delay faults transition, path analog faults for more examples, see section 4. Earth scientists use the angle of the fault with respect to the surface known as the dip and the direction of slip along the fault to classify faults. Thrust faults form nappes and klippen in the large thrust belts. Faults which move along the direction of the dip plane are dipslip faults and described as either normal or reverse thrust, depending on their motion. The fault surface can be vertical, horizontal, or at some angle to the surface of the earth. A normal fault may therefore become a reverse fault and vice versa.
Provides a normallyopen contact for remote indication. The participants did not have access to the regional seismic line, which would have provided context for such lowangle normal faults, or to the actual depth of. The purpose of the paper models is to help undergraduate students visualise a range of 3d geometries associated with faults. Extensional forces, those that pull the plates apart, and gravity are the forces that create normal faults. Earth fault protection using overcurrent relays nptel. The models are easy to build and can be downloaded free. Additionally, it is often stated that where one earth fault has developed, a second is likely to follow. The expanding and waxing flow bypasses the slope without recognizable deposition within the visibility limit of 8 vol. Similar flow is then released towards the tip model 2 and towards the centre model 3 of a normal.
Sensitive earth fault a core balance ct should be used to drive the sensitive earth fault function. The terminology of normal and reverse comes from coalmining in england, where normal faults are the most common. Ground fault current distribution when a ground fault. There is also a third type where the fault moves horizontally. Normal faults involve a dipping fracture surface on which the block above the fault plane, the hangingwall block, is downthrown with respect to the block below, called the footwali block. Because of the separation of geological horizons that results from normal faulting, such faults are also termed extension faults. An earth fault 7,5 % off the neutral also gives a 50 hz voltage equal to. For voltage this will require a five limb voltage transformer with an open delta tertiary winding, alternatively 3 single phase interposing transformers may prove suitable. Print or photocopy the model on heavy photocopy paper no heavier than. Faults which move along the direction of the dip plane are dipslip faults and described as either normal or. Cut out the fault model and fold each side down to form a box with the drawn features on top. What is the difference between earth fault and ground fault. Fault a fracture in the earths crust where one side moves relative to the other fault plane the flat planar surface along which there is movement during an earthquake foot wall a block of crust that is located above the fault plane normal fault a fracture in the earths crust where the hanging wall moves down. All of the paper models show displacement on the fault by the use of arrows and by the offset of a marker bed or a stream.
This box is a three dimensional model of the top layers of the earths crust. A reverse fault is the opposite of a normal faultthe hanging wall moves up relative to the footwall. When dominance fault collapsing is used, it is sufficient to consider only the input faults of boolean gates. Jul 14, 2015 this model of normalfault earthquake is different from the ideal elasticrebound model. Earth faults are normally located by splitting the feeder into sections and closing the. For example, a short circuit is a fault in which current bypasses the normal load. In this earths layers worksheet, students build a model of the earths layers with colored paper including the crust, the mantle, the inner core and the outer core. This model of normalfault earthquake is different from the ideal elasticrebound model.
Subsequently, energization is by manual intervention. Draw the normal fault as represented by the model you have just constructed. Fault a fracture in the earth s crust where one side moves relative to the other fault plane the flat planar surface along which there is movement during an earthquake foot wall a block of crust that is located above the fault plane normal fault a fracture in the earth s crust where the hanging wall moves down. Note that the zero sequence component is absent in normal load current or. A normal fault brings younger rocks over older ones. For more information about the usgs fast finite fault project, see the pager reference site usgs events for which there is a finite fault model from dr.
Deformation of rocks geology 200 geology for environmental scientists. There are also models and discussions of two faultproduced landforms, a graben and a horst these models are intended to help students and others visualize. Fault classes normal fault a normal fault is a high angle, dip slip fault on which the hangingwall has moved down relative to the footwall. Earth prints is an open archive created and maintained by istituto nazionale di geofisica e vulcanologia. This the earths layers foldable worksheet is suitable for grade. Lesson plans and activities indiana geological and water. To model the third type of fault, have students take the second cardboard piece that represents a crosssectional view of the layers of the earth and make a line at a 60 angle from a point at the top, dividing the cardboard piece into two see figure 4. Then, the method developed for determination of the ground fault current distribution when. The stresses and strains in the earths upper layers have many causes. A normal fault occurs when rocks break and move because they are being pulled apart. At least partly motivated by the incompatibility between fault. Nahm and others published normal fault find, read and cite all the research you need on researchgate. Subduction zones are a special class of thrusts that form the largest faults on earth and give rise to the largest earthquakes. Illustrate fault motion this exercise has students develop a model of a normal fault.
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