Table of Contents Introduction .......................................................................................2 Monitoring and Managing Electrical Power with ACCESS .......4 Electrical Power Distribution ..........................................................5 Voltage and Current Values .............................................................9 Changes in Voltage and Current ...................................................16 Frequency and Harmonics ........................................
Introduction Welcome to another course in the STEP 2000 series, Siemens Technical Education Program, designed to prepare our sales personnel and distributors to sell Siemens Energy & Automation products more effectively. This course covers Power Monitoring and Management with ACCESS and related products.
This knowledge will help you better understand customer applications. In addition, you will be able to describe products to customers and determine important differences between products. You should complete Basics of Electricity before attempting Power Monitoring and Management with ACCESS. An understanding of many of the concepts covered in Basics of Electricity is required for Power Monitoring and Management with ACCESS.
Monitoring and Managing Electrical Power with ACCESS Siemens ACCESS™ is more than just power meters, trip units, and other hardware. The ACCESS power management and control system is a networked system comprised of a variety of devices that monitor and control an electrical distribution system. The ACCESS system provides electrical data necessary for troubleshooting, power quality studies, preventative maintenance, and cost allocation.
Electrical Power Distribution Before discussing the Siemens ACCESS system an understanding of the production, distribution, and use of electric power is necessary. Electric power is produced by converting potential energy into electricity. There are several sources used to produce electric power. Coal, oil, and uranium are fuels used to convert water into steam which in turn drives a turbine. Some utilities also use gas or a combination of gas and steam turbines.
Distribution In order for generated power to be useful it must be transmitted from the generating plant to residential, commercial, and industrial customers. Typically, commercial and industrial applications have higher demands for electric power than residential applications. Regardless of the size of the electric system, electric power must be supplied that allows the intended loads to operate properly.
Loads Electricity is used to produce motion, light, sound, and heat. AC motors, which account for about 60% of all electricity used, are widely used in residential, commercial, and industrial applications. In today’s modern commercial and industrial facilities there is increased reliance on electronics and sensitive computer-controlled systems. Electronic and computer systems are often their own worst enemy.
Review 1 1. Which of the following is a benefit to using the Siemens ACCESS system? a. Reduce or eliminate unplanned outages b. Proactively manage power systems c. Automate sub-billing of utility power bills d. Optimize capital equipment used in power systems e. Measure and analyze power quality f. All of the above 2. AC motors account for about ____________ % of all electricity used. 3.
Voltage and Current Values An accurate measurement of voltage supplied by the utility and the current produced by the connected load is necessary in identifying power usage and power quality problems. DC Voltage is either direct current (DC) or alternating current (AC). DC voltage produces current flow in one direction. DC voltage can be obtained directly from sources such as batteries and photocells, which produce a pure DC. DC voltage can also be produced by applying AC voltage to a rectifier.
AC Voltage, Current, and Frequency Current flow in AC voltage reverses direction at regular intervals. AC voltage and current are represented by a sine wave. Sine waves are symmetrical, 360° waveforms which represent the voltage, current, and frequency produced by an AC generator. If the rotation of an AC generator were tracked through a complete revolution of 360°, it could be seen that during the first 90° of rotation voltage increases until it reaches a maximum positive value.
AC voltage can either be single- or three-phase. While singlephase power is needed for many applications, such as lighting, utility companies generate and transmit three-phase power. Three-phase power is used extensively in industrial applications to supply power to three-phase motors. In a three-phase system the generator produces three voltages. Each voltage phase rises and falls at the same frequency (60 Hz in the U.S.
Peak-to-Peak Value The peak-to-peak value is measured from the maximum positive value to the maximum negative value of a cycle. If the peak voltage is 650 volts, the peak-to-peak voltage is 1300 volts. Instantaneous Value The instantaneous value is the value at any one particular time along a sine wave. Instantaneous voltage is equal to the peak voltage times the sine of the angle of the generator armature. The sine value is obtained from trigonometric tables.
Average Value The average value of a sine wave is zero. This is because the positive alternation is equal and opposite to the negative alternation. In some circuits it may be necessary to know the average value of one alternation. This is equal to the peak voltage times 0.637. The average value of a distribution system with 650 volts peak, for example, is 414.05 volts (650 x 0.637).
Linear Loads It is important at this point to discuss the differences between a linear and nonlinear load. A linear load is any load in which voltage and current increase or decrease proportionately. Voltage and current may be out of phase in a linear load, but the waveforms are sinusoidal and proportionate. Motors, resistive heating elements, incandescent lights, and relays are examples of linear loads.
Crest Factor Crest factor is a term used to describe the ratio of the peak value to the effective (RMS) value. A pure sinusoidal waveform has a crest factor of 1.41. A crest factor other than 1.41 indicates distortion in the AC waveform. The crest factor can be greater or lower than 1.41, depending on the distortion. High current peaks, for example, can cause the crest factor to be higher. Measuring the crest factor is useful in determining the purity of a sine wave.
Changes in Voltage and Current Even the best distribution systems are subject to changes in system voltage from time-to-time. The following industry terms can be used to describe given voltage conditions. Voltage changes can range from small voltage fluctuations of short duration to a complete outage for an extended period of time. Term Condition Voltage Fluctuations Increase or decrease in normal line voltage within the normal rated tolerance of the electronic equipment.
Sags and undervoltage can be caused when high current loads, such as large motors are started. Undervoltage may also occur when a power utility reduces the voltage level to conserve energy during peak usage. Undervoltage is also commonly caused by overloaded transformers or improperly sized conductors. Swells and overvoltage can be caused when high current loads are switched off, such as when machinery shuts down.
In this illustration, however, loads are unevenly divided. A large number of lighting and small appliance loads are connected to phase C . This can cause the voltage on phase C to be lower. Because a small unbalance in voltage can cause a high current unbalance, overheating can occur in the C phase winding of the 3-phase motor. In addition, the single-phase motors connected to phase C are operating on a reduced voltage. These loads will also experience heat related problems.
CBEMA and IEEE The U.S. Department of Commerce, working with the Computer Business Equipment Manufacturers Association (CBEMA), published a set of guidelines for powering and protecting sensitive equipment. These guidelines were published in 1983 in FIPS Publication 94. As the use of computers has grown, other organizations have made additional recommendations.
Power Disturbance Types There are three types of power disturbances. Type I disturbances are transient and oscillatory overvoltages lasting up to 0.5 Hz. Type I disturbances can be caused by lightning or switching of large loads on the power distribution system. Type II disturbances are overvoltages and undervoltages which last from 0.5 to 120 Hz. Type II disturbances can be caused by a fault on the power distribution system, large load changes, or malfunctions at the utility.
Review 2 1. ____________ is a measurement of the number of alternations between positive and negative peak values in a measured amount of time. a. voltage b. current c. frequency d. power 2) The peak-to-peak value of an AC voltage with a peak voltage of 600 volts is ____________ . 3) The instantaneous voltage measured at 120° of a sine wave with a peak voltage of 650 volts is ___________ . 4) The most common method of expressing the value of AC voltage and current is ____________ value. a. average b.
Frequency and Harmonics We learned earlier that frequency is a measurement of the number of times voltage and current rises and falls to alternating peak values per second. Frequency is stated in hertz. The standard power line frequency in the United States is 60 hertz (60 cycles per second). In many other parts of the world the standard frequency is 50 hertz. Harmonics Harmonics are created by electronic circuits, such as, adjustable speed drives, rectifiers, personal computers, and printers.
When a harmonic waveform is superimposed on the fundamental sine wave a distinctive waveform is produced. In this example, the third harmonic is seen superimposed on the fundamental frequency. The problem of waveform distortion becomes more complex when additional harmonics are present. Total Harmonic Distortion Harmonic distortion is a destructive force in power distribution systems.
Harmonic Sequence A harmonic’s phase rotation relationship to the fundamental frequency is known as harmonic sequence. Positive sequence harmonics (4th, 7th, 10th, ...) have the same phase rotation as the fundamental frequency (1st). The phase rotation of negative sequence harmonics (2nd, 5th, 8th, ...) is opposite the fundamental harmonic. Zero sequence harmonics (3rd, 6th, 9th, ...) do not produce a rotating field.
Harmonic Effects All harmonics cause additional heat in conductors and other distribution system components. Negative sequence harmonics can be problematic in induction motors. The reverse phase rotation of negative harmonics reduces forward motor torque and increases the current demand. Zero sequence harmonics add together, creating a single-phase signal that does not produce a rotating magnetic field. Zero sequence harmonics can cause additional heating in the neutral conductor of a 3Ø, 4-wire system.
K Factor 26 K factor is a simple numerical rating that indicates the extra heating caused by harmonics. A transformer’s ability to handle the extra heating is determined by a K factor rating. A standard transformer has a rating of K-1. A transformer might have a rating of K-5, which would be an indication of the transformer’s ability to handle 5 times the heating effects caused by harmonics than a K-1 rated transformer.
Power and Power Factor Load Types Distribution systems are typically made up of a combination of various resistive, inductive, and capacitive loads. Resistive Loads Resistive loads include devices such as heating elements and incandescent lighting. In a purely resistive circuit, current and voltage rise and fall at the same time. They are said to be “in phase.” True Power All the power drawn by a resistive circuit is converted to useful work. This is also known as true power in a resistive circuit.
Inductive Loads Inductive loads include motors, transformers, and solenoids. In a purely inductive circuit, current lags behind voltage by 90°. Current and voltage are said to be “out of phase.” Inductive circuits, however, have some amount of resistance. Depending on the amount of resistance and inductance, AC current will lag somewhere between a purely resistive circuit (0°) and a purely inductive circuit (90°).
Reactive Loads Circuits with inductive or capacitive components are said to be reactive. Most distribution systems have various resistive and reactive circuits. The amount of resistance and reactance varies, depending on the connected loads. Reactance Just as resistance is opposition to current flow in a resistive circuit, reactance is opposition to current flow in a reactive circuit. It should be noted, however, that where frequency has no effect on resistance, it does effect reactance.
Reactive Power Power in an AC circuit is made up of three parts; true power, reactive power, and apparent power. We have already discussed true power. Reactive power is measured in volt-amps reactive (VAR). Reactive power represents the energy alternately stored and returned to the system by capacitors and/or inductors. Although reactive power does not produce useful work, it still needs to be generated and distributed to provide sufficient true power to enable electrical processes to run.
Power factor can be given as a percent or in decimal format. The following table shows the power factor for a few sample angles. Angle Theta 0 10 20 30 45 60 70 80 90 Cosine of Angle Theta 1 0.98 0.94 0.87 0.70 0.50 0.34 0.17 0 Power Factor (%) 100% 98% 94% 87% 70% 50% 34% 17% 0% Power Factor (Decimal) 1 .98 .94 .87 .7 .5 .34 .17 0 In purely resistive circuits, apparent power and true power are equal. All the power supplied to a circuit is consumed or dissipated in heat.
Power Factor Problems It can be seen that an increase in reactive power causes a corresponding decrease in power factor. This means the power distribution system is operating less efficiently because not all current is performing work. For example, a 50 kW load with a power factor of 1 (reactive power = 0) could be supplied by a transformer rated for 50 kVA. However, if power factor is 0.7 (70%) the transformer must also supply additional power for the reactive load.
The following table shows the amount of apparent power (VA = W ÷ PF) required for a manufacturing facility using 1 MW (megawatt) of power per hour for a few sample power factors. If, for example, a manufacturing facility had a power factor of 0.70 the utility company would have to supply 1.43 MVA (mega voltamps) of power. If the power factor were corrected to 0.90 the power company would only have to supply 1.11 MVA of power.
Power Demand Demand is the average energy consumed over a specified period of time. The interval is usually determined by the utility company and is typically 15 or 30 minutes. The utility measures the maximum demand over the 15 or 30 minute period. Utility companies must install larger equipment to handle irregular demand requirements. For this reason utility companies may charge large customers an additional fee for irregular power usage during peak times.
Solutions As we have learned, there are a number of things that can affect power quality. The following table provides some basic guidelines to solve these problems. It should be remembered that the primary cause and resulting effects on the load and system should be considered when considering solutions.
Review 3 1. The second harmonic of a 60 Hz power supply is ____________ Hz. 2. Typically, the total harmonic distortion (THD) of a voltage waveform should not exceed ____________ %. 3. ____________ sequence harmonics do not produce a rotating magnetic field. a. Positive b. Negative c. Zero 4. A transformer’s ability to handle the extra heating caused by harmonics is determined by a ____________ rating. 5. In a purely ____________ circuit, voltage and current are in phase. a. resistive b.
ACCESS System Up to this point we have looked at how various factors effect power quality. The following sections will focus on components of the ACCESS system and how they can be used as a complete power monitoring and management system. Supervisory Devices In general, ACCESS works on two levels: supervisory and field. Supervisory devices, such as WinPM™, collects and displays information from a network of field devices.
WinPM and SIEServe WinPM WinPM™ is supervisory software designed for monitoring and control of any facility’s electrical distribution system. WinPM can run on a single computer or in a networked environment. Multiple computers running WinPM can share data and control devices over a LAN using TCP/IP. WinPM can monitor an entire electrical system consisting of hundreds of field devices in multiple locations.
Analysis Power quality, such as transients, sags, swells, and harmonics, can be monitored and analyzed by viewing triggered waveforms, continuous data sampling, relay trip logs, and setpoint event messages. Historical data logs can be generated to provide load profile information, kilowatt demand usage patterns, harmonic, and power factor trends. These historical data logs can provide trending on any measured value.
Industrial Computer 40 Siemens software, such as WinPM and SIEServe, will run on most personal computers. In some applications it may be desirable to locate a supervisory computer in a harsh industrial environment. The Siemens industrial personal computer was designed for this purpose. The Siemens industrial computer is dust proof and drip proof to NEMA 4, NEMA 4X, and NEMA 12 specifications. There is a 10.4” flat screen monitor and full keypad with an integrated pointing device.
Communication Protocols and Standards The ACCESS system allows a variety of devices to communicate electronically. In the following illustration, for example, several power meters are connected to a single computer. Straight-Line Topology Field devices can be connected to supervisory devices with either straight-line or loop topology. In straight-line topology the supervisory device connects to a field device, which in turn connects to another field device, terminating at the farthest device.
Loop Topology In loop topology the cable is connected in a similar manner to straight-line topology. Rather than terminating the connection at the farthest device, a complete loop is formed by bringing the cable back to the supervisory device. Loop topology requires more cable than straight-line topology, which adds expense to the system and shortens the distance from the last device on the loop to the supervisory device.
ModBus RTU ModBus RTU is a protocol originally developed by MODICON, which is now part of Schneider Automation. ModBus RTU protocol has been widely used by other companies. DNP 3.0 Distributed Network Protocol 3.0 (DNP 3.0) was developed by Harris Distributed Automation Products. This protocol is an open and public protocol based on standards developed by the International Electrotechnical Commission (IEC). This protocol is often used by large power utility companies.
Local Area Networks Local Area Network (LAN) In any complex power monitoring system the need for rapid information flow is critical. Conditions at any point in the system may impact the entire power distribution system. This need for information flow often requires that intelligent devices, such as supervisory PCs, be interconnected by a local area network (LAN). A LAN is a communication system designed for private use in a limited area.
Ethernet Converter The Siemens Ethernet converter connects many ACCESS field devices throughout a facility to a supervisory computer. The Ethernet converter can be configured so that Siemens ACCESS components can communicate through the Ethernet or Token Ring. The Ethernet converter can connect RS-232 and RS-485 devices directly to a LAN. The converter is also capable of connecting up to two protocols, such as SEABus and ModBus RTU.
Serial Communication RS-232 and RS-485 are Electronic Industries Association (EIA) specifications commonly used for serial data communication. Siemens ACCESS devices support the RS-485 as standard. Some ACCESS devices also support the RS-232 standard. RS-232 46 RS-232 is a serial communication protocol which sends and receives information through twisted pair cable. It is common to see both 9-pin and 25-pin RS-232 connectors.
RS-232 uses what is referred to as an unbalanced signal or communication method. There is one signal wire for each circuit with a common return. The driver sends a series of binary signals to the receiver. These binary pulses make up predefined words that either give the status of a system being monitored or provide commands to control an event. This method is susceptible to unwanted electrical noise.
Typically, at the top level of a communication system is a host computer with an RS-232 interface. The host computer may have to communicate with an RS-485 device. In this situation a converter, such as a Siemens isolated multi-drop converter can be used. Isolated Multi-Drop Converter 48 The Isolated Multi-Drop Converter is an RS-232 to RS-485 converter that provides connectivity between a computer’s RS232 serial port and a Siemens SEABus RS-485 communications loop for ACCESS field devices.
Using the Isolated Muli-Drop Converter In the following illustration a computer communicates with various ACCESS field devices through an RS-232 interface and isolated multi-drop converter. Communicating on a LAN Field devices in the Siemens ACCESS product line that cannot communicate directly on a LAN, such as Ethernet, can be connected to the LAN through an Ethernet converter. When more than 32 field devices are used an isolated multi-drop converter is also required.
Modem Modems are electronic devices used for sending and receiving data over long distances. The Siemens ACCESS system also supports data communication through a modem. In the following illustration a remote computer communicates to an isolated multi-drop converter through a modem. Fiber Optics Fiber optics is a method for transmitting data using light. A basic system consists of a transmitting device which generates a light signal, a fiber optic cable, and a receiving device.
DTU3005 The DTU3005 is a multiple-function data transfer unit, which acts as an intelligent device to request information from up to 32 ACCESS devices. The requested information is then made available to PLCs and various industrial automation networks such as ModBus and PROFIBUS DP. There are two models, the DTU3005-P and DTU3005-B. The following illustration shows two possible configurations. Up to 32 Siemens ACCESS devices can be connected to one port of the DTU3005.
Local Display Unit The Local Display Unit (LDU) works with the SEABus network to poll data from Siemens ACCESS compatible devices. The LDU can be mounted in harsh industrial environments and is suitable for mounting in panelboards, switchboards, and switchgear. The LDU can be connected through SEABus to up to 32 ACCESS devices. A second port can be connected through RS-232 to a WinPM monitoring station.
Review 4 1. WinPM is an example of a ____________ device. a. supervisory b. field 2. A Siemens ACCESS power meter is an example of a ____________ device. a. supervisory b. field 3. The rules that govern the communication fo the ACCESS system are known collectively as ____________ and ____________ Plus. 4. A ____________ is an active device, such as a computer or printer, connected to the network. 5. Siemens ____________ ____________ can connect RS-232 and RS-485 devices directly to a LAN. 6.
Power Metering In today’s electronic environment, power management requires sophisticated meters. Voltage, current, and kW meters alone do not provide an adequate indication of power quality and energy consumption. Siemens power meters, in addition to measuring voltage, current, frequency, harmonics energy, power, and power factor, also capture system disturbances, log historical data, monitor the status of other equipment, and control loads.
Meter Location Power meters should be located at key points in the electrical distribution system to effectively monitor power consumption and quality. In some applications, it is sufficient to monitor energy consumption on significant loads and monitor power quality at the utility supply point. In critical power applications it may be desirable to monitor power quality throughout the distribution system.
9230 Meter The 9230 power meter measures real power. It will provide a readout of watts, watt-hours, and watt demand (configurable demand period). The 9230 is a full four-quadrant power meter providing bidirectional monitoring and separate positive and negative watt-hour accumulators. The 9230 meter measures voltage and current to calculate power. Alarm functions can be programmed to operate two relay contacts. A KYZ relay provides pulses for energy management systems.
4300 Meter The 4300 meter provides a readout of phase current, average phase current, line voltage, average line voltage, frequency, watts, watt-hours, peak watt demand, and power factor. Like the 9230, the 4300 is a full four-quadrant power meter. A standard communications module connects the 4300 to the Siemens ACCESS system. A separate display eliminates the need for voltage transformers on most low voltage applications because line voltage can be connected directly to the base module.
9240 Meter The 9240 meter provides all significant parameters of the power system including; 3-phase volts, 3-phase current, neutral current, watts, VAR, VA, watt-hours, power factor, and frequency. The 9240 records the maximum and minimum values for most measured parameters. Three KYZ pulses are available for energy readings. The 9240 uses standard cutouts and will replace most existing analog meters. The 9240 has several protocol options to support many systems.
The 9300 includes a front optical data port for accessibility by a portable PC. 9330 Meter The 9330 meter offers the same features as the 9300 meter. In addition, the 9330 includes setpoint capability to operate any of the four binary outputs. All events are recorded in the event log. The 9330 can also sample data continuously for future trend analysis. The 9330 meter features Ethernet or telephone modem connections as options.
4700 Meter In addition to providing information on all significant parameters of a power system, the 4700 includes waveform capture for harmonic analysis up to the 63rd harmonic. The 4700 includes 4 binary inputs and 1 analog input to monitor external equipment. There are 3 relay outputs that can be operated by set-points or used as kWh and kVARH pulse signals. The 4700 meter also includes one transducer-type analog output.
9500 Meter The 9500 offers three-phase power monitoring on a large, easy to read screen. The 9500 meter monitors K-factor, crest factor, individual harmonics, and total harmonics up to the 63rd harmonic. In addition to displaying values, the 9500 also displays graphical phasor diagrams and bar graph representations. The 9500 provides a 0.5 cycle trigger and up to 4 MB of memory for extensive waveform recording of system disturbances, as well as a special sag/swell module.
Another unique feature of the 9500 is the optional ability to connect to the Global Position Satellite (GPS) system for time synchronization with other 9500 meters in the distribution system.
Power Meter Features Siemens power meters have various features, depending on specific application needs. With a number of meters to choose from it may seem confusing when trying to decide which meter is right for which job. The following chart and tables are provided to help identify various features and performance capabilities for Siemens power meters. The chart is arranged in order of performance feature. The table on the following page details available features for each power meter.
Data Logging Display I/O Advanced Functions Communications 64 Real Power Bi-Directional Energy Sliding Window Demand Reactive & Apparent Power Voltage & Current Power Factor Frequency Harmonic Analysis Thermal & Predicted Demand Power Harmonics Symmetrical Components Min/Max Data Sampling Event Logging Waveform Recording Easy to read Alpha-numeric Display High resolution graphical Display Relays/Pulse Outputs Counter/Status Inputs Analog Outputs Analog Inputs Set-point Control Phase Reversal / Unbalanc
Review 5 1. Power meters should be located at ____________ points in the electrical distribution system. 2. The ____________ and ____________ meters include a front optical data port for accessibility by a portable PC. 3. The 4720 meter provides on-board harmonic analysis up to the ____________ harmonic. 4. A unique feature of the 9500 meter is the optional ability to connect to ____________ for time synchronization with other 9500 meters in the distribution system. 5.
Protective Relays and Trip Units The term switchgear is used to describe coordinated devices used for control and protection of equipment such as generators, transformers, capacitor banks, motors, and distribution lines. SIPROTEC 7SJ61, 62, and 63 are microprocessor-based protective relays designed to provide protective relay functions, metering, and control associated with switchgear circuit breaker installations.
SIPROTEC SIPROTEC is a trade name used by Siemens to identify a group of Siemens multifunction protection relays, such as the 7SJ61, 7SJ62, and 7SJ63. Multifunction protection relays provide the basic protection required in power systems, such as phase and ground overcurrent protection on feeder circuits, motors, and transformers. However, since they are microprocessor based, they can also communicate what is happening to the equipment they are protecting.
Circuit Breaker Trip Units The following sections describe low voltage insulated case (ICCB), molded case (MCCB) circuit breakers, and Type RL circuit breakers with Static Trip III™ available for use with the ACCESS system. ICCB 68 Siemens Sentron® ICCB circuit breakers are available in ratings from 800 to 5000 amps and are designed to supply high short time withstand and high interrupting ratings.
The TL trip unit features a full range of industry standard protective settings. The high-performance Systems Breaker Energy Communicating trip unit (SB-EC Trip Unit) offers advanced metering, protective relaying, time-stamped logs, and power quality monitoring functions. An LCD graphical display provides real-time voltage and current waveforms. MCCB Siemens Sentron MCCB circuit breakers are available in a digital version, referred to as Sensitrip® III.
Type RL Circuit Breaker Siemens RL series low voltage power circuit breakers are used in Siemens low voltage switchgear. RL series circuit breakers are designed for up to 600 volt service with current capacities up to 5000 amps. The RL circuit breaker in the following illustration is shown with a Static Trip III™ trip unit. Static Trip III Static Trip III™ units are microprocessor controlled, overcurrent protective devices for use on Type RL low-voltage power circuit breakers.
The Static Trip III consists of four models: III IIIC IIICP IIICPX Static Trip Family Basic Overcurrent Protection Added Communications and Current Metering Added Power Metering Extended Protective Relaying A standard feature of the Static Trip IIIC, IIICP, and IIICPX trip units is an alarm output. Any measured parameter can be set to activate the alarm based on threshold and time delay set points.
SAMMS The Siemens Advanced Motor Master System (SAMMS™) is a microprocessor-based motor control and protection device. SAMMS LV units provides all motor starting functions and thermal protection. SAMMS is a compact system with programmable control logic that replaces timers, control relays, push-buttons, selector switches, pilot devices, and associated wiring.
ACCESS Communication SAMMS connects to SEABus through an optional SAMMS Communication Module (CM-1). The CM-1 provides an RS-485 interface to communicate with the ACCESS system.
S7 I/O Device The S7 I/O™ device is an addressable modular input/output (I/O) device that links power system components to the ACCESS system. This device is a programmable logic controller (PLC), customized to communicate using SEABus. PLCs consist of input modules or points, a central processing unit (CPU), and output modules or points. An input to a PLC may come from a variety of digital or analog signals from various field devices.
The S7-I/O device provides the capability to monitor and control power system elements that are not specifically designed for ACCESS. Remote monitoring of any device equipped with an auxiliary contact is possible. Inputs such as the temperature relay of a motor or transformer can be input into the I/O device. Status of any circuit breaker with auxiliary contacts can also be monitored. This is especially useful to monitor MCCB status when metering functionality is not required.
Lighting Control System Lighting accounts for a large percentage of commercial and industrial power consumption. With a lighting control system, interior and exterior lights can be controlled via override switches, photocells, motion sensors, and a time clock. This will significantly cut energy costs as well as offer a safe and userfriendly environment for occupants. New energy codes are requiring lighting control on a state-bystate basis. ASHRAE 90.
LCP Products The LCP (Lighting Control Panel) family of lighting control systems is perfect for commercial applications such as schools, recreation centers, fast food, office buildings, prisons, and a variety of other applications. Depending on the specific LCP product, a lighting control panel can have up to 32 inputs and outputs. Four models are available: LCP 500, LCP 1000, LCP 1500, and LCP 2000. The LCP comes fully assembled with all specified relays in a NEMA 1 enclosure.
System Accessories Several accessories are available to enhance the operation of LCP products. A photocell can be used to control lights based on the amount of ambient light in an area. Touch-tone phone control (LCP TIM) allows you to use any phone to override the lighting. The LCP 2000 seamlessly integrates with HVAC and building management systems via the ModBus gateway. This integration allows control by other systems of each individual LCP relay or group of relays from a single RS-485 connection.
ACCESS System Application Example The following illustration shows an example of Siemens ACCESS system including hardware, software, and field devices. In this example Siemens power meters are located throughout the distribution system. Siemens software, WinPM and SIEServe, are used to record voltage, current, power, and harmonic events for use in other parts of the system.
Review 6 1. ____________ is a trade name used by Siemens to identify a group of multifunction protection relays. 2. Siemens Sentron ICCB circuit breakers are available in ratings from 800 to ____________ amps. 3. Static Trip III overcurrent protective devices for use on Type ____________ low-voltage power circuit breakers. 4. Static Trip ____________ features extended protective relaying. a. III b. IIIC c. IIICP d. IIICPX 5. ____________ is microprocessor-based motor control and protection device.
Review Answers Review 1 1) f; 2) 60; 3) current; 4) a Review 2 1) c; 2) 1200; 3) 562.9; 4) b; 5) 1.
Final Exam The final exam is intended to be a learning tool. The book may be used during the exam. A tear-out answer sheet is provided. After completing the test, mail the answer sheet in for grading. A grade of 70% or better is passing. Upon successful completion of the test a certificate will be issued. Questions 1. Which of the following is a supervisory device? a. c. 2. 0.707 1.41 b. d. 0.
5. Type ____________ disturbances last up to 0.5 Hz. a. c. 6. b. d. 2nd 4th power factor correction capacitors a UPS system K-rated transformers a voltage regulator 9230 4720 b. d. 4300 9500 The ____________ meter includes a front optical data port for accessibility by a portable PC. a. c. 10. 1st 3rd The ____________ meter has a high resolution graphical display. a. c. 9. Type II Type IV To help reduce the effects of harmonics it may be necessary to install ____________ . a. b. c. d. 8. b.
11. The rules that govern the communication of the ACCESS system are known collectively as ____________ . a. c. 12. star all of the above CBEMA Electronic Industries Association Institute of Electrical and Electronic Engineers U.S. Department of Commerce SIEBus VISION TOUCH WinPM SIEServe 4 128 b. d. 32 232 ____________ protective relays are designed to provide protective relay functions, metering, and control associated with switchgear circuit breaker operation. a. c. 84 b. d.
17. The Static Trip ____________ provides basic overcurrent protection, metering, and extended protective relaying. a. c. 18. b. d. IIIC IIICPX ____________ is a motor control protection device a. c. 19. III IIICP SAMMS Static Trip III b. d. SIPROTEC Sensitrip W hich of the follow ing m eters doesnot feature harmonic analysis? a. c. 20. 9300 9230 b. d. 4700 9500 Which of the following meters features GPS time synch? a. c. 9230 9330 b. d.
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