Abstract: An engine generator set control system includes an engine, a generator, a frequency selection interface, a voltage regulator, and a controller. The engine includes a variable geometry turbocharger (VGT) and a crankshaft. The controller generates a signal indicative of a desired VGT configuration as a function of the selected frequency.

Abstract: An overvoltage protective device for wind energy installations is designed for connection to a connecting line having at least one inductance between a wind energy installation and a grid system. The overvoltage protective device has a controller which operates a limiting unit as a function of an overvoltage at the wind energy installation. The limiting unit comprises a spur line having an induction module and a power tapping module which is provided with a switching unit. This yields a second power strand which can accept a considerable reactive current if necessary, thus increasing the voltage drop across the inductance, as a result of which the voltage acting on the wind energy installation is reduced.

Abstract: An electrical power control system for use with a recreational vehicle or similar load to selectively control power thereto from either a utility power source or a generator power source comprising a power control stage coupled to the utility power source and the generator power source by a power supply stage to operate the electrical power control system and a utility/generator switch arrangement to selectively direct the power from either the utility power source or the generator power source to the recreational vehicle and wherein the power control stage monitors polarity, phase and voltage levels and controls the utility/generator switch arrangement to selectively feed power from either the utility power source or the generator power source to the recreational vehicle under a predetermined plurality of operating parameters or conditions and fault conditions.

Abstract: A method for protection of an energy storage source (2), in particular a battery of a motor vehicle, against possible overloading caused by prolonged application of an electric voltage to the energy storage source, this voltage being generated at least partially by a rotary electric machine (1) such as an alternator or an alternator-starter, the method comprising the following steps: permitting measurement of a charge level of the energy storage source, this charge level being represented for example by a voltage measured at the terminals of the energy storage source or a PWM signal, whilst the rotary electric machine is functioning in a predetermined functioning mode, and electric excitation is being applied to it; comparing a value (SENSE) of this measurement with a reference value (Max_SP); if the value measured for the energy storage source is greater than the reference value, interrupting the excitation applied to the rotary electric machine.

Abstract: A control system for an electrical power generation system (EPGS) provides overload protection without disconnecting a generator of the EPGS from an excessive electrical load. Available engine power and current levels of the electrical load are continuously measured and computed. A command voltage is calculated in real time that corresponds to a voltage required to sustain with the maximum available power. Output voltage of a generator of the EPGS is controlled at the calculated command voltage so that a power limit of the engine is not exceeded during electrical overload conditions.

Abstract: There is disclosed a permanent current switch which has a high temperature margin and which is thermally stable and which securely performs a switching operation between a superconducting state and a normal conducting state. The permanent current switch of the present invention has a coiled superconducting wire and a heater wire which switches the superconducting wire between the superconducting state and the normal conducting state, the superconducting wire is a magnesium diboride superconducting wire having a high-resistance metal on an outer side and a magnesium diboride superconducting portion on an inner side and prepared by forming a superconducting metal on a layer between the high-resistance metal and the magnesium diboride superconducting portion, and the permanent current switch further comprises a superconductive connecting section superconductively connected to a lead wire guided from the superconducting wire and a superconducting wire for a wiring line.

Abstract: A controller employed in conjunction with a synchronous generator monitors the output voltage of the generator. The controller employs the monitored output voltage as feedback that is used to control the excitation provided to an exciter field winding. In addition, the controller applies a control loop to the monitored output voltage that detects and modifies voltage ripple signals within the monitored output voltage to generate a compensated signal that is used to control the excitation to the exciter field winding. In particular, by detecting and modifying voltage ripple signals within the monitored output voltage, the controller is able to counteract armature reaction voltage ripples caused by unbalanced short-circuit faults, thereby preventing the build-up of voltage on the DC link.

Abstract: A method of protecting an electromechanical power transfer system from excessive peak electrical potentials, the power transfer system comprising a prime mover, a dynamoelectric machine coupled to the prime mover for generating multiphase alternating current (AC) power, and at least one multiphase AC electrical load coupled to the dynamoelectric machine by way of a multiphase AC power bus, the dynamoelectric machine having a control coil responsive to control current for varying power supplied to the electrical load, comprises the steps of: analysing electrical potentials on the power bus to generate analysed power bus characteristics; comparing the analysed power bus characteristics to predetermined power bus characteristics; simultaneously shunting power across the power bus and reducing control current to the control coil for the dynamoelectric machine when the analysed power bus characteristics approximate the predetermined power bus characteristics to reduce the measured electrical potentials; and simult

Abstract: A control system is disclosed. The control system has an electric machine coupled to provide power to or receive power from a DC bus and a controller in communication with the electric machine and the DC bus. The controller is configured to receive a voltage from the DC bus, compare the voltage from the DC bus to a characteristic indicative of a fault of at least one winding of the electric machine, and take a precaution based on the comparison.

Abstract: A vehicle alternator control device in which, when a signal detection portion detects a determined input signal, an operating mode of an overvoltage warning portion is switched to a detection operating mode by an overvoltage warning operating mode switching portion. In the detection operating mode, the overvoltage warning portion is activated when a voltage below a determined voltage has continued for a time that is less than a determined time. Accordingly, checks related to the operation of the overvoltage warning portion can be completed in a short time at a plant or the like.

Abstract: An electrical power control system for use with a recreational vehicle or similar load to selectively control power thereto from either a utility power source or a generator power source comprising a power control stage coupled to the utility power source and the generator power source by a power supply stage to operate the electrical power control system and a utility/generator switch arrangement to selectively direct the power from either the utility power source or the generator power source to the recreational vehicle wherein the power control stage monitors polarity, phase and voltage levels, and controls the utility/generator switch arrangement to selectively feed power from either the utility power source or the generator power source to the recreational vehicle under a predetermined plurality of operating parameters or conditions and fault conditions.

Abstract: One embodiment of the present application is directed to a protection technique for a back-up electric power generation system. This system includes an electric power generator, generator control circuitry, electrical output sensors to provide one or more corresponding signals, electrical switching equipment to selectively couple the generator to an electrical load, and electric power feeder conductors to route electric power from the generator to the switching equipment. The control circuitry is responsive to the sensor signals to determine if a shut-down condition exists as a function of a protection profile determined for the system. This profile may account for damage thresholds of the generator, the feeder conductors, and the electrical switching equipment for each of a number of different combinations of level and duration of electrical output as represented by the sensor signals.

Abstract: A field discharge circuit may rapidly reduce the field current of a generator, thereby avoiding an overvoltage condition. The field discharge circuit of the present invention may use another storage device, such as a capacitor, to quickly transfer the field current energy thereto and then slowly dissipate the transferred energy after the event (such as removal of a load) has passed. By transferring this energy to a storage device and subsequently slowly discharging this energy through a resistor, electromagnetic interference caused by a conventional resistive discharge can be reduced.

Abstract: A method for protecting an electrical generator which includes providing an electrical generator which is normally synchronously operated with an electrical power grid; providing a synchronizing signal from the electrical generator; establishing a reference signal; and electrically isolating the electrical generator from the electrical power grid if the synchronizing signal is not in phase with the reference signal.

Abstract: Systems and methods are disclosed to construct subsurface images from diffuse seismic energy. Various disclosed system embodiments include multiple seismic sensors that each convert received seismic energy into one or more seismic signals. One or more processor combine the seismic signals to determine a subsurface map. As part of determining the map, the processor(s) systematically focus the array of seismic sensors on each bin in the subsurface volume of interest. In this manner each bin becomes a focal point of the array. For each bin, the processor(s) analyze the seismic wave travel time to each seismic sensor and apply a corresponding time shift to align the seismic signals with a uniform travel time. The time-shifted seismic signals are then combined to determine an intensity value for seismic energy radiating from the focal point. A subsurface map can then be derived from the intensity value as a function of position.

Abstract: In accordance with the present invention, modular corona shields are employed in a HTS device to reduce the electric field surrounding the HTS device. In a exemplary embodiment a fault current limiter module in the insulation region of a cryogenic cooling system has at least one fault current limiter set which employs a first corona shield disposed along the top portion of the fault current limiter set and is electrically coupled to the fault current limiter set. A second corona shield is disposed along the bottom portion of the fault current limiter set and is electrically coupled to the fault current limiter set. An insulation barrier is disposed within the insulation region along at least one side of the fault current limiter set. The first corona shield and the second corona shield act together to reduce the electric field surrounding the fault limiter set when voltage is applied to the fault limiter set.

Abstract: A vehicle alternator control device in which, when a signal detection portion detects a determined input signal, an operating mode of an overvoltage warning portion is switched to a detection operating mode by an overvoltage warning operating mode switching portion. In the detection operating mode, the overvoltage warning portion is activated when a voltage below a determined voltage has continued for a time that is less than a determined time. Accordingly, checks related to the operation of the overvoltage warning portion can be completed in a short time at a plant or the like.

Abstract: A managing method of the start-up phase of at least one micro fuel cell to be connected to a load includes: measuring a micro fuel cell voltage value across the micro fuel cell activated by means of a fuel injection; comparing the micro fuel cell voltage value with a first threshold voltage value; and establishing an operation mode of the micro fuel cell as follows: as long as the micro fuel cell voltage value is lower than the first threshold voltage value, the micro fuel cell operates in a first open circuit state, during which it is not connected to the load; when the micro fuel cell voltage value overcomes the first threshold voltage value, the micro fuel cell passes to a second pre-ignition state, during which it supplies a current value corresponding to the first threshold voltage value, according to a static voltage-current characteristic of the micro fuel cell.

Abstract: The present invention provides systems and methods that allow for individual power sources to be disconnected and reconnected without interrupting the power supply from the other power sources and that allow for these power sources to provide power at substantially the same electrical parameters such as frequency, phase, and voltage.

Abstract: A diode system and a generator, uses Zener diodes. The diode system has AC voltage terminals and DC voltage terminals, in which the Zener diodes are operable in the forward direction to rectify an AC voltage present at the AC voltage terminals, in which a lower limit is provided for the Zener voltage of the Zener diodes, and in which the lower limit of the Zener voltage is provided so that it is lower than a preset lower DC voltage.

Abstract: A power generating system wherein a variable speed turbine is mounted on top of a tower or tethered underwater. The reactive component of turbine generated electrical power is corrected automatically through electronic switched power-factor capacitor banks that are divided into sub-system modules coupled to a central turbine park sub-station. The sub-system modules are of a fixed size and are easily adaptable to different turbine generator types, sizes and groupings. By employing SCR switched power factor capacitors grouped in sub-system modules of fixed size, coupled to a central turbine park sub-station, the converter allows fast, real time control of the utility interconnected power line voltage or power factor.

Abstract: A static excitation system that can eliminate shaft vibrations of a generator and overvoltage when it is underexited is provided. The static excitation system includes an initial excitation equipment; a step-down transformer; a 3-phase diode bridge; a boost chopper provided with a transistor and a resister, and maintaining DC voltage to be constant; a DC chopper provided with a plurality of transistors and diodes, and supplying DC power to a rotor of a generator; a boost controller for controlling the boost chopper; and a DC chopper controller for controlling the DC chopper, wherein, overvoltage applied on the excitation system when underexcited is eliminated owing to the boost chopper preventing any changes at an output terminal of the generator from being transferred to the excitation system, and maintaining the excitation DC voltage to be constant; and also owing to the DC chopper which is capable of 4 quadrant operation, hereby pole slipping of the generator can be prevented.

Abstract: A liquid crystal device (LCD) driver circuit includes first through N-th input pads for respectively receiving first through N-th voltages (N>1). First through N-th electrostatic discharge (ESD) protection units are respectively connected to the first through N-th input pads, and form a discharge path when an electrostatic pulse is respectively applied through any of the first through N-th input pads. An output driver has first through N-th resistors. The first through N-th resistors respectively receive the first through N-th voltages input through the first through N-th input pads. The output driver generates a driving voltage for driving an LCD from each of the first through N-th voltages received through the first through N-th resistors, respectively. The first through N-th resistors reduce a current flowing into the output driver when the electrostatic pulse is applied. Some or all ESD protection units may include a thin gate-oxide (gox) transistor.

Abstract: A DC/DC converter features a programmable controller in a feedback control loop thereof. The programmable controller enables easy changes to operating parameters by reprogramming the controller's application software. Additionally, the converter features a hardware-implemented fault protection circuit which shuts down the converter's switching transistor upon controller failure.

Abstract: A fire detection system comprising a control panel comprised of one or more controllers for controlling a plurality of devices. A pair of lines are operably connected to the control panel and the devices for communicating signals between said control panel and said devices. A circuit for providing a polarity sensing power and signal interface is provided between the control panel and devices to reduce to reduce system maintenance. The circuit includes a rectifier circuit operably connected the pair of lines wherein the rectifier circuit is comprised of at least two transistors for providing the circuit with a low-impedance path to ground and providing the circuit with a polarity insensitive output. Capacitors may be operably connected to the transistors in the rectifier circuit to keep the transistors turned on when a low voltage is applied to the rectifier circuit.

Abstract: A method and a device for protecting a matrix converter is disclosed. The matrix converter has nine bi-directional circuit-breakers which are arranged in a 3×3 switch matrix. A highest potential is detected from all input and/or output potentials or from all input potentials and at least one output potential. Bi-directional circuit-breakers of the matrix converter are controlled when a predetermined threshold value is exceeded. This arrangement protects the entire matrix converter from overvoltages. The converter can be produced easily and cost-effectively.

Abstract: A microcircuit includes core and other portions, which receive different supply voltages from disparate sources. An electrostatic discharge protection (ESD) circuit internally connects the lower and higher voltage terminals together with a diode, poled so that the diode conducts if the nominally lower voltage supply exceeds the higher voltage supply. If the high voltage supply fails or even drops below the value of the low voltage supply, the diode conducts, and current is drawn in an amount which may overheat the microcircuit. A shut-down circuit is provided for sensing the voltage of the higher-voltage source, and shutting down the lower-voltage source any time the higher-voltage source drops below either the actual voltage (in one embodiment) or nominal voltage (in another embodiment) of the lower value source.

Abstract: A method for averting damage that may be caused by a transient energy surge during a load dump event, the method including detecting the load dump event and in response causing the consumption of transient excess energy due to the load dump event.

Abstract: A photodetector circuit having a power supply and an avalanche photodiode coupled electrically thereto. The power supply includes a first portion, which supplies a substantially constant current, and a second portion, which supplies a substantially constant voltage. At low to moderate optical input signal levels, the substantially constant current that is applied to the avalanche photodiode generates a biasing potential that provides a signal gain, the magnitude of which varies depending upon the optical input signal level. A bias filter between the power supply and the avalanche photodiode slows changes in bias voltage so that the instantaneous photocurrent follows the modulation on the input optical signal. With constant average current bias, the bias potential automatically adjusts with temperature and sample variations to give the same average current flow.

Abstract: A system and method for conditioning a power transmission, thereby eliminating adverse characteristics from the power transmission. The system selectively includes a voltage surge protector, an EMI/RFI filter and at least one inrush current suppressor integrally formed into a single system. To condition an incoming power transmission, the power transmission is passed through the voltage surge protector to eliminate any abnormal voltage spikes. The power transmission is then passed through an improved EMI/RFI filter having a dual output. The outputs of the EMI/RFI filter lead into a first inrush current suppressor. The inrush current suppressor limits the amperage of the power transmission for a predetermined period of time and then permits unrestricted current flow.

Abstract: A microprocessor motherboard and system include a microprocessor having external input and external output connections. The microprocessor includes a conductive path formed between one of the external input connections and an external output connection for routing a supply voltage to the external output connection. The microprocessor, therefore, selects an appropriate bus voltage for communicating with peripheral circuitry. New generations of microprocessors can be implemented without changing the remaining motherboard configuration.

Abstract: A genset controller that is configurable for controlling a variety of types of gensets, as well as a method of configuring a genset controller for controlling a genset, are disclosed. The genset controller includes a memory for storing a plurality of software routines, a personality profile data set, and a user-settable data set, and further includes a processor coupled to the memory for executing the software routines and reading data from the personality profile data set and the user settable data set to control the genset. The genset controller additionally includes an input port coupled to the memory for enabling changes to the personality profile data set and the user-settable data set to be downloaded into the memory. The personality profile data set and the user-settable data set include data that configures the genset controller for operation with a particular genset.

Abstract: The protecting apparatus includes a circuit for automatically and continuously determining the difference voltage between the voltage at the input side of a connecting circuit breaker and the voltage at an output side thereof between an electric generator and an associated power system, following initiation of closure of the connecting circuit breaker. The difference voltage is representative of the voltage angle of the generator relative to the electrical system. The difference voltage is compared against a reference value, which is selected such that a voltage angle value greater than the reference value will result in damage to the generator and/or the electrical system. An output signal is developed which can then be used to trip circuit breakers serving the electrical system if the reference value is exceeded by the difference voltage.

Abstract: An electrical power distribution system having geographically separated plural generation stations and geographically separated loads is improved by dynamically offsetting a nominal real power operating point of a main control system driving a power control element that variably feeds electrical power onto a network of transmission lines between the stations and the loads in response to deviations in frequency and/or phase of alternating current power on the network. The generation station can include an actuator control circuit for driving the control element in response to a power setting signal, the actuator control circuit incorporating a delay component, an offset signal connection downstream of the actuator control circuit bypassing the delay component. Preferably the system further includes means for monitoring a threshold level of the deviations, and means for inhibiting the means for dynamically offsetting until the deviations exceed the threshold level.

Abstract: An overvoltage protective arrangement to protect an electrical installation against overvoltages, which installation has an onboard power supply system fed by an electrical D.C. generator (9) and electrical devices connected thereto. The overvoltage protective arrangement is provided with a limiting device whose threshold value is above the rated generator voltage.

Abstract: A control apparatus controlling the operation of pulse width modulator for an electric clutch or electric motor in portable spray painting equipment having a pressure transducer for sensing the pressure, a manually adjustable pressure reference, a comparator type error detector, and a pressure deadband control for inserting a deadband in a pressure control loop with the deadband varying as the pressure reference varies. A fixed deadband is provided below a predetermined low pressure setting to avoid excessive cycling of the control apparatus during low pressure operation. The pulse width modulator control circuit includes compensation for improving input power factor. The clutch control includes an active alternative load circuit switched in when the alternator output voltage is above a predetermined value.

Abstract: A self-test system for a shorted diode protection circuit in an electric vehicle propulsion system includes a series of relays for selectively coupling a battery in circuit with a field winding of a generator, the shorted diode protection circuit being coupled in voltage sensing arrangement with the field winding. The relays are operated to induce current in forward and reverse directions through the winding in separate test stages. At each stage the winding is disconnected from the battery so that inductive reactance creates a voltage on the winding to actuate the protection circuit. A system controller records whether the protection circuit is responsive and therefore operable and alerts a vehicle operator.

Abstract: An overvoltage protection circuit utilizes the fault current sensing capabilities of a differential protection circuit in combination with a shunting circuit to protect a power generating system against an overvoltage condition. The circuit offers the combined advantage of protecting attached load equipment from the harmful effects of an overvoltage condition while also ensuring rapid deexcitation of a generator.

Abstract: A system for implementing accurate V/Hz value measurement and trip time determination for generator/transformer overexcitation protection independent of the conventional frequency tracking and phasor estimation based on Discrete Fourier Transformation (DFT) techniques. The half-cycle summation technique of the invention is a non-recursive digital technique which measures the per unit V/Hz value by summing the sampled data points in every half cycle of a sinusoidal input signal and dividing the sum with the ideal base sum value. When the input voltage signal is sampled at a reasonable frequency, the technique of the invention approximates the accurate per unit V/Hz value of the input voltage signal and thus obtains an accurate V/Hz characteristic directly without computing voltage and frequency separately.

Abstract: A three-phase alternator protection component is associated with a rectifying bridge. Three Shockley diodes and an avalanche diode are interconnected through three electrodes, of a first polarity, of the Shockley diodes, and the electrode, of the opposite polarity, of the avalanche diode to a common terminal that is connected to the output terminal, having a first polarity, of the rectifier. Each second electrode of the Shockley diodes is connected to each output of the alternator, and the second terminal of the avalanche diode is connected to the second output terminal of the rectifier.

Abstract: There is disclosed a device for detecting an abnormality in relays which is adapted such that if there is a current flow through a motor (M) when first and second transistors (Q1, Q2) are off resulting from an abnormality such as melting of first and second motor driving relays (RL1, RL2), a controller (1) turns on the transistors (Q1, Q2) of a motor driving portion (2) in response to a detection signal from a signal detecting portion (3) and accordingly provides the same potential across the motor (M) to stop the motor (M) without a conventionally complicated, costly construction.

Abstract: A protection circuit for a brushless excitation system is provided which directly monitors the output voltage of the diode bridge rectifier of the system. The protection circuit includes a reference signal generator subcircuit which provides a reference signal which tracks the dc output voltage of the diode bridge. The reference signal can vary as the system voltage is varied under certain circumstances. The protection circuit also provides for the calculation of a predetermined percentage of the reference signal voltage to create a tolerance band for testing the actual output voltage of the diode bridge rectifier. The percentage represents an acceptable limit of the ratio of a peak-to-peak ripple of the reference signal to the dc voltage of the reference signal. Using the reference signal and the percentage value to create a tolerance band, a comparator is used to test the actual output voltage of the diode bridge to determine if the output voltage is within the tolerance band.

Abstract: A shorted diode protection system for a traction vehicle propulsion system including a synchronous generator having armature and field windings and a bridge rectifier circuit coupling the generator armature windings to a traction motor employs a normally non-conducting solid-state controllable electric valve in parallel with the generator field windings. When a rectifier diode of the bridge rectifier circuit fails short, an a-c current is reflected into the generator field winding circuit. Upon detection of this reflected current, the valve is switched into a conducting state, thereby limiting the voltage on the generator field windings.

Abstract: Loss of excitation and control and subsequent damage to exciter windings in an excitation system for dynamoelectric machines wherein one or more rotating diodes fail in a shorted mode is prevented through the use of an RC circuit for detecting AC voltages in an exciter field winding for the purpose of directly operating a circuit breaker to remove excitation to the field windings and supply or to activate a timer for such purposes while temporarily shorting the AC current through the exciter field winding.

Abstract: A portable power unit has a protective circuit for cutting off an output current from the power unit when the power unit is in an overload state. An amount of the output current is detected. An output voltage from the power unit is reduced when the amount of the output current detected reaches a first threshold value, thereby preventing the protective circuit from undesirably operating for one power unit when it is connected for another for parallel operation. When the amount of the output current decreases to a second threshold value which is smaller than the first threshold value, with the power unit being in a state in which the output voltage is reduced, the voltage-reducing operation is canceled.

Abstract: A protection system minimizing utilization equipment's exposure to, and power interruption resulting from, an under voltage condition in an electric power generating system includes generator current sensors, generator speed information, an exciter current sensor, voltage sensors, and a controller.

Abstract: An electrical generator system integrated controller device utilizing PID control and capable of regulating voltage or current, and frequency simultaneously. The device utilizes a micro-controller (30.1) to monitor the engine generator set (20), then determines the appropriate signal to deliver to the electrical generator set (20) to regulate the engine throttle (21) and the generator (22) field windings. The micro-controller (30.1) also provides for real and reactive load sharing with additional generator sets (40) while also providing for an integrated circuit interrupter module (500) to open the line from the generator (22) to the load bus (42). Additionally, serial communications (34) are provided as well as displays (35), meters (37), and operator input (36). Finally, the permissive paralleling module (700) provides that the engine electrical generator set (20) will not be allowed to be connected to the load bus (42) until standards of voltage and phase have been achieved for a set period of time.

Abstract: Disclosed is an apparatus for controlling a solenoid switch connecting a power supply to a load. The apparatus constantly monitors the level of output voltage of the power supply, and accordingly controls the engagement or disengagement of the solenoid switch. Initially at the time the power switch is just turned on, the solenoid switch would not be engaged until the voltage has reached a predetermined level. After the solenoid switch is engaged and power is delivered to the load, the apparatus would disengage the solenoid switch when the voltage level of the power supply goes beyond an upper limit or below a bottom limit. Utilizing the apparatus, the power input to the load can be kept in a desired range.

Abstract: An engine-driven power generating system comprising a bridge circuit section in which a low-frequency switching elements driven alternately by low-frequency drive signals, and high-frequency switching elements driven by high-frequency drive signals during the ON period of the low-frequency switching elements are connected in a bridge network, and an inverter circuit section having a drive signal supply circuit for supplying low-frequency and high-frequency drive signals are each supplied to the low-frequency and high-frequency switching elements that form a pair; the a-c voltage generated by an engine-driven a-c generator is converted into d-c voltage that is in turn converted into a predetermined level of low-frequency a-c voltage; characterized in that an emergency relay circuit device for protecting the engine-driven power generating system against abnormal operating condition.

Abstract: A connection control device for controlling the connection of a small generator unit, which is installed at the consumer's location, to an electric power system. The connection control device detects variations in frequency components which result from interruptions in the distribution of electric power to the consumer from the electric power system. When a significant variation in a frequency component is present, the connection control device disconnects the consumer from the electric power system in order to prevent injury to line workers.