TECHNICAL CHARACTERISTICS OF GENERATORS FOR THE INDUCTION HEATING OF THE FIFTH GENERATION OF THE TFC-5 SERIES

Technical characteristics of generators (in the range from 50 Hz to 22 kHz, from 25 kW to 4 MW)

1. Basic data

1.1. The series of frequency converters of the fifth generation of TFC-5 according to the nomenclature of frequencies and power was expanded in relation to previous generations of TFC, the frequency from 50 Hz to 22 kHz, power from 25 kW to 4 MW (in a single TFC). General operating conditions of the series of ТПЧ-5 are given in table 1, the main parameters are given in table 2.

Table 1 Operating conditions of series ТПЧ-5

The name of indicators Units Numeric values
1 Ambient temperature °C 0–40
2 Cooling water inlet temperature, not more °C 35
3 Humidity ambient % 90
4 Dust level up to мг/м3 20
5 The degree of protection of equipment in the cabinet, not less IP 55
6 Warranty period ТПЧ-5 from the moment of shipment год 2.5

 

Table 2 The main parameters of the series TFC-5

The name of indicators Units Numeric values
1 Rated output power range Pn * 1) кВт 25; 32; 40; 50; 63; 80; 100; 125; 160; 200; 250; 320; 400; 500; 630; 800; 1000; 1250; 1600; 2000; 2500; 3200; 4000
2 A number of frequency ranges, where each separate frequency range with a double frequency change refers to a separate version of TFC-5 * 1) кГц 0.05÷0.1; 0.15÷0.3; 0.25÷0.5; 0.5÷1; 0.75÷1.5; 1.25÷2.5; 2÷4; 5÷10; 8÷16; 11÷22
3 Rated voltage range at output Un * 1) В 400; 500; 800; 1000; 1600; 2000
4 A range of nominal line voltages of the Uab network at the input, 50 or 60 Hz 1 *) В 3х380; 3х550; 3х660; 3х1000
5 Tolerance voltage input % ±5
6 Output voltage control range:
– at a rated voltage of Un = 800V and below— at a rated voltage of Un = 1000V and above
В 100 ÷ Un

200 ÷ Un

7 Power control range relative to maximum % 1 ÷ 100
8 Allowable variation range of the parallel active component of the resistance of the circuit Re, normalization is performed with respect to the value Re = Rn in the nominal mode Re/Rn 0.5 ÷ 5
9 Accuracy of voltage stabilization Ue when Re is changed by 2 times in any segment of the allowed Re range (if there is no current limitation) % ±2

* 1) By agreement it is allowed to order the value not in a row

Basic circuit of ТПЧ-5 series in the range from 50Hz to 22kHz, from 25kW to 1.25 MW

Image1. Basic circuit of TFC-5 series in the range from 50 Hz to 22 kHz, from 25 kW to 1.25 MW

"Diagram of powerful versions of TFC-5C from 1.6 MW to 4 MW

Image2. The scheme of powerful versions of ТПЧ-5С from 1.6 MW to 4 MW

1.2. Example of marking the performance of the source:

ТПЧ 5 M 320 1.0 800 380
1 2 3 4 5 6 7

1. The name of the series.
2. Fifth generation.
3. The group of structures (A, M, C), item 1.6.
4. Rated power output, table 2, paragraph 1.
5. The upper frequency limit, Table 2, p. 2.
6. Rated voltage at the output, Table 2, p.3.
7. Rated mains voltage, Table 2, p.4.
The source must meet the requirements for all items of Table 2 in the double frequency range (50..100%) without changes in the power section (only the load circuit itself, which actually sets the frequency, changes).

1.3. The basic circuit of TFC-5 (Fig. 1) includes a rectifier (Rectifier), a DC link and an inverter (Inverter). In Figure 1, instantaneous values ​​of quantities are indicated by lowercase letters in italics. In tables and text, bold capital letters without italics are put in the notation for mean or effective values, for example: average choke current Id, effective circuit voltage Ue, effective linear voltage Uab. The DC link contains the filter capacitance Cd, the choke Ld and the diode-transistor chopper based on IGBT (Chopper). Chopper regulates the current in the choke Ld. The CeLeRe parallel load oscillating circuit is connected to the output of the inverter and determines the output frequency of the inverter, which is slightly higher than the resonant frequency of the circuit.

1.4. In order to improve the quality of the power supply in the network, the circuit of powerful versions of TFC-5 is built on the basis of a 12-pulse rectifier (Fig.2). The rectifier is powered from a transformer with two groups of secondary windings shifted in phase by 30 ° according to the “star” scheme of the first group and the “triangle” of the second group. As a result, on the primary side of the transformer, a high quality of the form of current consumed is achieved (proximity to a sinusoid).

1.5. The rated voltages at the output of the sources are consistent with the rated voltages of the circuit capacitors. By agreement of the Manufacturer with the Customer, non-standard nominal voltages can be used – see Note 1 to Table 2.

1.6. Sources TFC-5 is divided into 3 groups by design:
1.6.1. In the group ТПЧ-5А (the letter “A” from the word “Air”), from 25 kW to 320 kW, all heat-generating components are cooled by air. The semiconductor components are of modular type and screwed to a common radiator, for construction, see p.3.4. At low power, up to 80 kW, the fan is not put – using natural cooling.
1.6.2. In the group ТПЧ-5М (the letter “M” from the word “Module”), from 125 kW to 500 kW, modular-type thyristors are used, which are screwed to a plate with liquid cooling (water). Water is isolated, has no electric potential, therefore there is no strict requirements for water purity and electrical conductivity. It is allowed to use running water in accordance with GOST 16323-79 taking into account additional requirements:
– at the entrance of the system, a grid should be installed with an opening size not exceeding 1×1 mm;
– the amount of insoluble precipitation (mechanical impurities) is not more than 12 mg / l;
– electrical resistivity of at least 4 kΩ · cm.

1.6.3. In the group ТПЧ-5С (the letter “C” from the word “Capsule” is a tablet), from 100 kW to 4 MW (in a single ТПЧ), liquid-cooled (water-cooled) tablet type thyristors are used. Water is under electrical potential; strict requirements are imposed on its specific electrical resistance: at least 50 kΩ · cm. Water quality should be ensured by a dual-circuit water cooling system using centralized or individual heat exchangers.

1.7. The characteristics of TFCs are mainly determined by the type of thyristors used in the inverter. Types of thyristors and their main parameters are presented in Table 3. As a rule, in all groups of sources ТПЧ-5А, 5М, 5С, one thyristor is used in each inverter arm. However, in the case of using thyristors with a short off time and a low class, two successive thyristors in the arm can be used.

Table 3 The main parameters of the inverter thyristors in the versions of ТПЧ-5А, 5М, 5С

Manufacturer Type of thyristor in the inverter Design Average current, A Class, V Off time tq, µs
Designs TFC-5A, 5M
1 Semikron SKKT-330/18 Modular 330 1800 50…150
2 Semikron SKKT-570/18 Modular 570 1800 100…200
3 Proton MTF3-375-15-A2 Modular 375 1500 16; 20; 25
4 Proton MTFS3-305-11-A2 Modular 300 1100 5; 6.3
5 Proton MTFS3-400-15-A2 Modular 400 1400 8; 10; 12.5; 16
6 Proton MTFS3-630-15-A2 Modular 630 1500 16; 20; 25; 32
7 Proton MTF3-420-21-A2 Modular 420 2100 16
Designs of TPCh-5S
1 Proton ТБ953-630-36 Tablet 630 3600 50
2 Proton ТБИ233-320-24 Tablet 320 2400 25; 32; 40
3 Proton ТБИ243-630-22 Tablet 630 2200 32
4 Proton ТБИ153-800-15 Tablet 800 1500 10; 12.5; 16
5 Proton ТБИ353-800-34 Tablet 800 3400 63; 80; 100
6 Proton ТБИ153-1000-15 Tablet 1000 1500 12.5; 16; 20; 25
7 Proton ТБИ153-1250-15 Tablet 1250 1500 16; 20; 25; 32
8 Proton ТБИ873-1600-40 Tablet 1600 4000 125; 160
9 Proton ТБЧ123-200-14 Tablet 200 1400 6.3
10 Proton ТБЧ133-400-12 Tablet 400 1200 5; 6.3; 8
11 Proton ТБЧ143-500-11 Tablet 500 1100 5; 6.3
12 Proton ТБЧ343-500-11 Tablet 500 1100 5; 6.3
13 Proton ТБЧ153-800-14 Tablet 800 1400 8; 10; 12.5; 16

1.8. In addition to the series connection of thyristors in the arm, a parallel connection to the common rectifier of two inverters can be used, each with its own choke Ld and its own line to the circuit, which guarantees a uniform division of the currents. In this case, for the second inverter, individual pulse control and alarm control are added (“tilting”, overvoltage, breakdowns of consecutive thyristors in 4 arms).

1.9. To increase the capacity, group operation of TFC-5 sources on the common load circuit is provided. For example, grouping two sources with a unit capacity of 4 MW will give a total power of 8 MW. This ensures, if necessary, the start-up and operation of one source per circuit without disconnecting the second source.

1.10. Table 2 in paragraphs 1-4 presents to the Customer a wide selection of the main output parameters of TFC-5 from standard series. Realization of a wide choice is provided by the Manufacturer ТПЧ-5 by using an automated design technology for the order. In each case, the Customer is offered, along with the prices, several versions of designs that reflect the specific needs of the Customer. Versions are provided to the Customer in the form of standard tables with parameters (datasheet), where in addition to the basic parameters from Table 2, paragraphs 1-4, additional parameters are also given:
– maximum temperatures of semiconductor devices in the field of operation of ТПЧ-5;
– maximum current values: in the inductor, at the input and output of the TFC-5;
– losses in power units, efficiency and output power of ТПЧ-5 at various voltages and frequencies;
– water consumption and pressure drop, fan power and noise;
– scheme with designations of electrical quantities;
– weight and size indicators.
If necessary, the Customer is assisted in the final choice of performance.

1.11. Sources of ТПЧ of previous generations generate higher harmonics of current into the power supply network, the frequency of which is tens and hundreds of times higher than the frequency of the power supply network. Higher current harmonics distort the sinusoidal shape of the mains voltage curve and interfere with other electrical consumers that are connected to the same network node. The outdated state standard GOST 13109-67, adjusted in 1970 and 1987, and valid until 01/01/1999, provided for the norm for the root-mean-square non-sinusoidal voltage coefficient KU = 5%, which counted only 12 harmonics – from the 2nd to the 13th Oh. At the same time, the distortion of the mains voltage from the influence of TFCs was due to the higher current harmonics. As a result, TPC sources up to the 4th generation could de jure satisfy the norm at the root-mean-square coefficient KU, but de facto interfered with other consumers.

The new intergovernmental standard GOST 13109-97, which complies with international IEC standards, signed by 9 countries and introduced since 01/01/1999, provides not only the norm for the root-mean-square coefficient KU = 8% (where 39 members are now introduced), but also standards for individual harmonic components from the 2nd to the 40th and further to infinity.

The power filter in the DC link of the fifth-generation TFC-5 source is designed to provide standards for all harmonic components and at the same time for the root-mean-square coefficient KU. Sources of ТПЧ-5 are allowed to be connected to the network node of sufficient capacity while observing the electromagnetic compatibility rules set forth in Appendix A.

1.12. Table 4 shows the advantages of the TFC-5 series in terms of the nomenclature and parameters compared to similar sources from other manufacturers (consideration up to 22 kHz).

1.13. Sources of the fifth generation of ТПЧ-5 with respect to previous generations of ТПЧ have increased reliability and improved characteristics in all aspects of operation – see section 2.

Table 4 Key parameters of sources from different manufacturers

Parameter Ed. aljuel.eu
Таллинн
termolit.com
Украина
reltec.biz
Екатеринбург
inductotherm.ru
США
ameritherm.com
США
kuraist.narod.ru
Уфа
rocinduktor.ru
Челябинск
1   Frequency range кГц 0.05÷22 1.0÷8.0 0.15÷10 0.2÷10 0.5÷15 0.5÷22 0.2÷6.0
2 Minimum / maximum rated power for versions with different frequencies
0.05÷0.1 кГц кВт 50/4000
0.25 кГц кВт 800/3600 150/1750 1000
0.3 кГц кВт
0.5 кГц кВт 50/1600 320/3600 200/800 800
1.0 кГц кВт 320/1500 250/500 100/750
2.5 кГц кВт 40/1600 50/630 250/1000 50/320 35/500 63/320 100/750
4.0 кГц кВт 50/500 160/800 63 50/200
8.0 кГц кВт 40/1250 50/350 100/250 20/500 160/320
10.0 кГц кВт 40/800 63/320 15/35 12/100
16÷22 кГц кВт 25/400 16/100
3   Group work
on the general contour (p.1.9)
+ +
4 Cooling options:
liquid + + + + + + +
airy + +
5 Compliance with the norms of influence on the network according to GOST 13109-97 +
6 Versatility (automated parameterization, p.2.16) +
7   Multi-frequency
mode (p.2.17)
+
8   Black Box (p.2.18) +
9   Internet Diagnostics (p.2.19) +
10   Model support for commissioning (p.2.20) +
11   Warranty period (clause 4.8), years 2.5

2. Improved performance specifications in relation to the previous generation of ТПЧ
2.1. High efficiency. Losses in TFC-5 are reduced due to the use of new technical solutions. A diode-transistor chopper (based on IGBT) is introduced into the classical parallel inverter circuit, which gives particularly significant advantages at low (below 0.5 kHz) and high (more than 4 kHz) frequencies. The inverter input current is intermittent, the current pause is supported by the chopper on limiting: at least 5 ° at frequencies up to 2.5 kHz, or at least 10 ° at higher frequencies. The advantages of the intermittent current mode at low frequencies are manifested in the fact that the installed power of the choke and the loss in it are significantly reduced by reducing the inductance. The advantages at high frequencies are manifested in the fact that there is no current switching (as in the classical current inverter), di / dt is reduced, there is no switching loss in the inverter thyristors and damping circuits. As a result of loss saving, high efficiency is ensured. For example, in the high-power performance of the TFC-5S-900-10.0-800-660, the efficiency value in the nominal mode is 97.3%. At frequencies up to 1 kHz in most versions, the efficiency value is above 98%.
2.2. Resistance to short circuits – this quality is preserved in TFC-5, as in previous generations, as the most valuable quality of the classical scheme. External (in load) and internal (closure of any power semiconductor) closures in all cases do not lead to the destruction of the structure and the violation of the presentation (soot, splashes of molten copper, etc.). When thyristor damage and short circuits at any points of the circuit, the protection system turns off the IGBT, which leads to the termination of the fault current. Also, damage to the IGBT itself (shutdown failure) should not cause damage to other power components, since the inverter remains in operation to absorb the residual (at the time of the accident) energy in the DC link. The inverter counter-emf prevents the buildup of the emergency current in the Ld choke while the last pair of rectifier thyristors is burning down. Then comes the safe discharge of the Cd filter capacity into the remaining inverter. Resistance to short circuits is a fundamental advantage in relation to transistor voltage inverters, where failure to turn off the IGBT for any reason (damage to the IGBT itself or a violation in control) leads to serious consequences (violation of the presentation).

2.3. The optimal choice of cooling. Cooling options are described in section 1.6. For low power versions, the air cooling method is preferable (TFC-5A group), since It gives maximum operational reliability. The question of “dirty” water is eliminated and there are no leaks. Such reliability can provide long-term operation without the participation of maintenance personnel. At relatively low power, up to the boundary of the order of 160 ÷ 250 kW, the sources of the TFC-5A group are relatively cheap and compact. However, starting with a power of about 250 ÷ 320 kW, the sources of the TFC-5M group are more compact, which are cooled by running water, which has conductivity but is isolated from the electric potential, in order to prevent corroding the nozzles by the currents flowing in the water. For powerful versions, of the order of 500 kW and above, the tablet design of the ТПЧ-5С and the dual-circuit cooling system with the use of centralized or individual heat exchangers, where pure (non-conductive) heat and running water are exchanged, are economically justified. Low cost and wide availability of thyristors after the expiration of the ТПЧ warranty period are also operational advantages of a tablet design. At the same time, the consumer can buy from the manufacturer of ТПЧ-5 any spare parts (p.4.5).

2.4. Improved thermal mode of low-current electronic equipment (control system) by reducing the air temperature inside the cabinet by separating the choke into a separate, heat-insulated, ventilated compartment, see paras. 3.3, 3.4. In old TFCs, heat leakage into the air from a water-cooled choke was a significant proportion, approximately 20..30%. Such a heat leak caused a significant heating of the air in the cabinet, which could cause failures in the control system at the maximum permissible ambient temperature (40 ° C) and at the same time at the maximum permissible water inlet temperature (35 ° C).

2.5. The rectifier is open (angle α = 0) in the entire area of ​​operation of the TFC-5. The cosine of the phase shift of the current in the supply network is close to 1. As a result, the reactive power is saved, and the distortion in the network is minimized. Rectifier adjustment is used only for smooth start-up of ТПЧ-5 in order to, firstly, avoid current inrush when charging the filter capacity, and secondly, severe emergency operation is prevented in case of an initially damaged power component (for example, IGBT defect) or errors in the power unit and management.

2.6. Reduced (excluded) peak voltages on the inverter thyristors. The introduction of the chopper allows you to use the intermittent current mode of the inverter. The peak reverse voltage on the thyristors is either zero (with certain combinations of input and output voltages of TFC-5), or insignificant even in the absence of damping RC circuits. As a result, the requirement for a class of thyristors sharply decreases, losses in damping RC circuits are reduced by an order of magnitude, or RC circuits are not put at all. The reliability of the inverter increases, one of the most frequent causes of damage to thyristors is eliminated – reverse voltage breakdown (in old TFCs, according to statistics, about 40%).

2.7. The inrush current in case of failure of the inverter commutation is excluded. The inrush current is characteristic of previous-generation TFCs, and in some cases is dangerous, since the rectifier has a delay in switching to the inverter mode during an emergency shutdown of the TFC. For example, if with an empty inductor a random breakdown of the commutation occurred (due to noise), as a result of which the current increased, then, in the case of recovery of oscillations (which is real with an empty inductor), the voltage on the load is much higher than the nominal one, and the thyristors can break down . However, in TFC-5, any emergency mode in the inverter is safe due to the chopper being disconnected from the power source.

2.8. Excluded is the most common cause of damage to thyristors – direct voltage breakdown. In previous generations of TFCs, with any violations, there is a potential danger of a voltage rise of the inverter above the nominal. When this rise occurs when the rectifier is open, it cannot be stopped and prevented due to the rectifier delay. This deficiency is the most common cause of damage to thyristors – according to statistics, about 50%. In this case, disconnection from the power source is performed by a chopper, which reliably prevents a voltage rise.

2.9. A controlled rectifier, a chopper and an inverter is a combination that has the property of mutual self-defense. If a rectifier or inverter fails (no matter in the power section or control), turning off the chopper in all cases leads to the opening of the current circuit. If, on the other hand, the chopper itself has suddenly deteriorated (the IGBT does not turn off), then the inverter absorbs the residual energy of the DC link (see Section 2.2). Double failure at the same time in the chopper and in the inverter is so unlikely that it is almost unreal. A global failure, for example, the loss of one of the supply voltages in the control system always causes the chopper to turn off and break the current circuit.

2.10. Efficiency in current limiting mode. According to Table 2, p. 8, the source should allow a change relative to the nominal point (Rn) parallel to the active component of the loop resistance (Re) by 2 times in the direction of decreasing Re / Rn = 0.5, and 5 times in the direction of increasing Re / Rn = five. In both cases, the power decreases below nominal. In old TFCs, the reduction in power at the Re / Rn = 0.5 point is approximately: minus 55..60%. In TFC-5, the rectifier is always open, so the percentage of power reduction at the point Re / Rn = 0.5 is much smaller, which depends on the ratio of input and output voltages. For example, at input voltage Uab = 660V and output Un = 1000V, the change in power in TFC-5 is minus 20%, and at Uab = 380 V and Un = 800V (or 1000 V), there is no decrease in power in TFC-5 – i.e. in the whole range of current limiting, Re / Rn = 0.5..1 power is equal to nominal. This effect significantly reduces the heating cycle.

2.11. Improved start method. The start-up method (discharge of the starting capacity) in TFC of previous generations requires a starting capacity of at least 20% of the capacity of the circuit. At low frequencies, very powerful discharge and charge circuits are also required in the Start Block. In the TFC-5, the start-up method has been changed: the chopper makes it possible to start the TFC-5 without a starting device, respectively, there is no selection of the starting capacity for a specific load. The new method has a high margin of switching stability, which makes it possible to reliably start at any point of the ranges indicated in Table 2.

It also eliminates the disadvantage of the old method: fire risk. In the old way, the discharge circuit is connected in parallel to the circuit. Since the thyristors of the Start Block are operating at high circuit voltage, breakdown due to class failure, or switching on by interference and other control disturbances is potentially possible. Breakdown with the formation of two-way conduction (short-circuit) will cause the starting capacitance to connect in parallel to the circuit as an additional capacitance. The inverter can, in principle, continue to operate (with a high di / dt value during switching) until a severe accident occurs with the ignition of the discharge wires of the Start Unit and with simultaneous failure of the inverter thyristors. To avoid ignition of wires, it is necessary to install expensive high-voltage fuses in the discharge circuit of the Start Unit. Fuses save from ignition, but the inverter thyristors fail. In addition, the fuses themselves sometimes fail at normal discharge of the starting capacity. Such a case is possible when a large starting capacity is required with a sufficiently large circuit capacity, which reduces reliability in operation.

2.12. Enhanced monitoring of TFC state. The current sensors of the rectifier and the inverter and thermal contacts in all fuel nodes are stored. The feedback transformer is replaced by a more reliable voltage sensor, in which the phase shift error is smaller and the frequency range is wider. Two additional voltage sensors are also introduced: to control the inverter’s emf and to control the rectifier voltage. Such control allows you to more reliably build a security system.

The counter-emf sensor allows you to monitor not only the direct, but also the reverse peak voltage on the thyristors, which increases the effectiveness of protection.

The rectifier voltage sensor is useful in that it allows you to more accurately and reliably diagnose complex emergency modes that are stored in the Black Box and in parallel in the Internet Diagnostics TFC database. The rectifier voltage sensor is not used in the control system. If necessary, it is allowed to connect the input wires of the sensor to any other points of the power circuit to control any voltage. After transferring the desired Waveform to the Black Box and / or to the Database, it is recommended to return the original connection.

The signal from the rectifier current sensor is used in the control system and for soft start, and is also very useful in analyzing alarm oscillograms. The rectifier current signal is an assembly of the phase currents at the input of the ТПЧ-5 (to the rectifier) ​​in order to remove the rectifier pulses as quickly as possible in any phase in any phase. This precaution is not superfluous, because in the event of a rectifier accident, severe consequences are excluded: violation of the integrity of the design and presentation of the converter, failure of the power circuit breaker, damage to the supply network of the Consumer.

2.13. Preserved the continuity of local (MPU) and remote (DPU) control panels in relation to previous generations of TFC. The circuit of the DPU remains unchanged, but at the same time the galvanic isolation of the C5 controller from the MPU and the DPU is ensured. As before, the MPU has buttons and lamps for Start, Stop, Alarm, Automatic Q1 and a separate voltmeter for the load voltage. Information on the MPU is displayed by analog instruments (which is more familiar and more comfortable for visual perception compared to the display) over 4 measurement channels: power and frequency at the output, current and voltage at the input of the inverter. To save space on the MPU, four devices can be replaced with one device with a 4 position switch. The novelty is that in case of emergency shutdown of ТПЧ-5 all 4 readings of the devices are “frozen” for convenience of monitoring the pre-emergency condition, i.e. arrows stop at the position preceding the accident. The emergency reset (and the “freeze” reset) is performed by the STOP button. A more complete control (monitoring) of the state of TFC-5 is performed on a personal computer – see p.2.14.

2.14. USB and RS-422 channels. A USB output is provided for connecting a personal computer, where a service program is launched that displays the readings of 4 channels of the MPU measuring instrument, all tuning constants and creates convenience for their adjustment and “firmware”. In addition, RS-422 long-distance communication (hundreds of meters) is provided for monitoring and receiving automation commands. Commands allow you to set the output voltage of the TFC-5 and thereby ensure one or another law regulating the temperature of the workpiece in the inductor. Team format and protocol are agreed with the customer.

2.15. The C5 controller has a developed service system, which covers parameterization, commissioning and maintenance of the TFC-5 in operation. The components of the service system are available on the website www.aljuel.eu on the pages: Service, Diagnostics. The service system includes the following tools:

– Automated parameterization provides versatility of the source of ТПЧ-5 (p.2.16);
– Multi-frequency mode TFC-5 provides automatic selection of the active set of tuning Constants in the case of switching output buses TFC-5 to another circuit (p.2.17);
– Black Box provides automatic saving (in the Flash memory) of the Emergency Waveforms in case of its occurrence (p.2.18);
– Internet Diagnostics provides the foundation of “rapid response” in operation (p.2.19);
– Model support provides reference oscillograms of start-up modes on the mathematical model TFC-5 (p.2.20).

2.16. Automated parameterization provides versatility of the TFC-5 source. The source should be provided with opportunities to work with a variety of circuits within all the requirements of Table 2. Individual adjustment for a specific circuit is provided on the basis of automated parameterization – the configuration file (QF) is being prepared for the “firmware” by service tools. All tuning constants CF are calculated automatically when entering individual parameters of the circuit (capacitance, natural frequency, line inductance). “Firmware” CF in Flash memory is carried out at the command of the User. If necessary, the service also provides for the online correction of individual adjustment constants.

2.17. Multi-frequency mode TFC-5. The configuration file (CF) includes 4 sets of tuning constants for 4 different load circuits, in which the natural frequencies fall at different points of the permissible frequency range. The maximum difference in frequencies at the edges of the range is twofold according to Table 2, paragraph 2. If the frequency difference of individual circuits is more than twice, then an additional winding lead (tap) must be provided in the choke Ld. Using desoldering allows you to change the inductance Ld and get the frequency range of the source more than twice. When the TFC-5 is started up, each time the contour is automatically recognized and, as a result, the set of Constants is set to be active, which must correspond to the contour. If TFC-5 operates on one circuit, all 4 sets of Constants are set the same.

2.18. The Black Box ensures that the last 5 fault oscillograms are saved. Service tools provide a convenient reading of oscillograms from flash memory and detailed display of signals in graphical form. The waveform contains 6 analog and 11 logical signals with sufficient resolution (2 μs) and covers the interval for reliable diagnosis of the nature of the accident (dozens of periods of the inverter). It also provides the ability to save non-emergency (standard) waveform.

2.19. Internet Diagnostics. Each saving of the Oscillogram in the Black Box is accompanied in parallel by sending the Oscillogram to the Internet. The transfer is carried out by the GSM modem built into the controller via a normal cellular network using a SIM card from any mobile operator. Oscillograms come to the database at www.aljuel.eu/c5/index.html, where a summary table of Oscillograms from all ТПЧ is displayed on the web page. The developed Oscillogram classification system, posted at www.aljuel.eu/Archive1/Diagnostics/html+pdf/c5-diagnostics.pdf, allows, according to strict rules, to record for each Oscillogram the result of its detailed examination – Diagnosis. The summary table shows the strict and short records of the Diagnoses of thousands of Oscillograms, which form the “knowledge base”. Internet Diagnostics is a powerful tool that allows the Manufacturer of TFC-5 in the most difficult cases to quickly respond to an emergency and provide immediate assistance to the Customer during the warranty and after-warranty period.

2.20. The model support provides for the free transfer to the Customer of the Oscillograms of the starting modes obtained on the mathematical model of TFC-5, where the actual parameters of the circuit are set. Model Oscillograms serve as reference standards for comparison with actual Oscillograms, which facilitates commissioning.

2.21. Standards are maintained for permissible voltage distortion of the supply network from the influence of the source of ТПЧ-5. See clause 11 of the commissioning of a new interstate standard GOST 13109-97. Requirements for network power, rules for connecting TFC-5 to the network node and ensuring electromagnetic compatibility, see Appendix A.

2.22. The coolant (water) in the choke Ld in the sources of ТПЧ-5 has zero electric potential – it is isolated from the winding (section 3.1).

2.23. Reliability assessment. De facto sources of the TPCh series of previous generations have a service life of 25 years or more. Additional reliability is introduced by technical solutions of the fifth generation listed above, therefore, the warranty period of operation is increased (Section 4.8) in relation to previous generations of TFC and in relation to other manufacturers of sources.

3. Construction

3.1. In power sources up to 1.25 MW, chokes with air cooling are used (Img. 3a), and starting from 1.6 MW power – with liquid (water) cooling (Img. 3b).

Appearance of air cooled chokes

Image3. Appearance of chokes with air (a) and liquid (b) cooling.

The winding of both types of chokes is made of wide thin (1 mm) aluminum sheets – foil. Special patented technology ensures the contact of aluminum foil with copper external leads. The use of foil allows you to combine the minimization of electrical losses and good heat removal in both air and liquid cooling. In the second case, a cooling profile (front and rear) is inserted inside the winding, through which the cooling fluid electrically isolated from the winding circulates (cooling with running water is allowed).

The winding of the choke is covered with three layers of insulating paper impregnated with varnish. The choke goes through a lacquer impregnation stage, for which it is aged in a hot lacquer bath, after which it takes hours of drying. The varnish layer is an effective protection against dust and at the same time significantly reduces the throttle noise. In addition, intrawinding dampers are used to reduce noise. At the request of the customer can be applied two or three layers of varnish. In the latter case, the protection is maximum (technology for underwater use).

3.2. Liquid cooled choke has 4 fluid channels. The inputs and outputs of the 4 channels are connected to the transfer case, which is visible on the left side of Fig.3b. On the box there are 4 input connections of the cooling channels, and on the other side of the box there are 4 output connections. Connecting hose jumpers to fittings, you can include channels in series or in parallel, as well as mixed. Switching options of the cooling channels allow optimal alignment of the pressure drop and the flow rate of the choke with another part of the cooling system that cools the semiconductor power unit.

3.3. Losses discharged from a liquid-cooled choke are distributed in proportion: 80% are discharged by the liquid, 20% go into the air. The task of removing air heat for both types of chokes, air and liquid, is solved in the same way: the cabinet is divided by a partition into two heat-insulated compartments, a choke is placed in the lower compartment and ventilation is provided. There are no ventilation holes in the upper compartment and a high degree of protection (Tab. 1, p. 5) of electronic equipment from dust and moisture without air circulation (see p. 3.4) is provided.

3.4. The TPC-5A group of the ribbed part of the radiator is enclosed in a closed vertical ventilation duct, which is included in the lower compartment of the cabinet. The leakage of heat into the air from the side of contact between the semiconductors and the cooler is insignificant in all groups of TFC-5A, 5M, 5C. Heat leaks are discharged through the walls of the upper section of the cabinet without forced air circulation.

3.5. The three input busbars are in the main variant on the left side in the upper part of the cabinet, alternatively on the top. Two output tires to the load on the basic version are located at the bottom, an alternative option – on the right side at the bottom of the cabinet. Horizontal mirror symmetry and other locations of input and output tires are possible upon agreement with the order.

3.6. The inductance of the line to the load from below is not limited, a zero inductance is allowed. Restrictive choke, as in the old ТПЧ, is not required. The limitation of the inductance of the line above must be agreed upon when ordering maximum permissible inductance depends on many parameters of ТПЧ-5.

3.7. Transformer for feedback signal is not required – see p.2.12.

3.8. Separate sources of ТПЧ-5 should be connected by separate lines to a high-power node (a network transformer), i.e. the rule of the radial distribution of the supply of individual sources must be observed in order to exclude an adverse effect on each other. The order should specify the length of the line for connecting the ТПЧ-5 to the network node and the node power (for short circuit current).

4. Prices, terms, guarantees
4.1. The customer sends an order to the Manufacturer of TFC-5 within the requirements of Table 1, Table 2, paragraphs. 3.5, 3.6, 3.8. If necessary, the Customer reports additional requirements. The manufacturer sends to the Customer, together with the prices, the possible variants of versions of TFC-5 in the form of standard tables with parameters (datasheet), see p.1.10. As a result, final performance is agreed upon. The manufacturer guarantees the Customer the best price / quality ratio.

4.2. If the order is not accepted, the price is valid 3 months from the date of approval.

4.3. Remote start-up support and operational Internet Diagnostics are included in the price of TFC-5.

4.4. The standard spare parts kit is included in the price of TFC-5. Spare parts kit can be extended under a separate contract. After the expiration of the TFC-5 warranty period, power semiconductor devices, thyristors and IGBT transistors, if necessary, are sold to the Customer at agreed fixed prices.

4.5. Payment is made in three parts: 50% in advance; 40% – payment before shipment; 10% – payment after completion of commissioning.

4.6. The delivery time of TFC-5 is 3..6 months from the date of advance payment of 50%.

4.7. The warranty period for TFC-5 is 2.5 years from the date of shipment (customs clearance).

ALJUEL, Estonia, Tallinn LLC NPP T5-Energy Systems, St. Petersburg www.aljuel.eu
(+372) 6-355-088, (+372) 53-731-742
This article was taken from this resource.