RU95434U1 - MULTIFUNCTIONAL ENERGY COMPLEX (IEC) - Google Patents

Abstract

 A combined multifunctional energy complex containing heterogeneous sources and an energy storage device connected to the inputs of a network and autonomous converters, the inputs of which are connected to a load, the outputs of the sensors of which are connected to the inputs of the aggregate automatic control systems of each converter, and the outputs of these systems are connected to the control circuits of each converter, characterized in that the network converter runs on high-voltage vacuum devices, and the outputs of agr converter control systems are connected to the input of the control unit of the upper level, the outputs of which are connected to the control circuits of the valves of each converter.

Description

The utility model relates to the field of electrical engineering, namely to hybrid energy complexes that provide uninterrupted power supply to the load while providing specified indicators of the quality of power supply and the presence of diverse sources of electricity.

The objective of the utility model is to provide guaranteed power supply to the load when using heterogeneous sources of electricity: diesel generators using synchronous generators (SG), wind power plants (wind turbines) with asynchronous generators (AG), photovoltaic installations (PMTs), electric energy storage devices (NEE) with using rechargeable batteries (AB) and / or fuel cells (TE). The multifunctional energy complex of the IEC should provide modes of charge, storage and discharge of NOE, eliminate voltage dips and surges, and dampen voltage swings on load buses, for example, when switching sources.

At least three types of IEC are known: stand-alone, network, and combined IEC.

Autonomous MEK.A is isolated from the network, runs on a passive load and contains 1-2 different sources, for example, SG (AG) and PMT, as well as an accumulator of NEE in the form of AB or TE. Such an IEC.A is carried out at low power (up to 0.1 MW) and low voltage (0.4 kV), for example, in the form of a solar-wind power plant with a NEE based on AB or TE. (V.M. Andreev, A.G. Zabrodsky, S.O. Kognovitsky “Integrated solar-wind power plant with energy storage based on the hydrogen cycle”, “Alternative Energy and Ecology of AEE” No. 2 (46), 2007 , pp. 99-105) [1].

The disadvantage of autonomous IECs is their insufficient power and, as a consequence, insufficient quality of energy supply.

The network IEC is characterized by the presence of additional communication with the power system through a dc-ac or dc-dc network converter. The network converter is designed to reverse power from an autonomous network to a power system or vice versa, and its power is determined by the load power and the excess (or insufficient) power of the sources of the autonomous system. An example of such a network IEC is the largest of the known installations in Fairbanks (USA) using NEE in the form of nickel-cadmium batteries with a capacity of up to 27 MW (discharge time 15 min), operating on a 138 kV power system (L. Gyugyi “Apparatus and method for interline power flow control ”, Patent US 5698969, class G05F 1/70, published 1997) [2].

Another example of a network IEC is an IEC with a NEE based on a 0.25 MW hydrogen cycle and a discharge duration of 5 ms to 30 s, connected to a 25 kV network, which maintains voltage stability on load buses from 2.2 to 4.6% ( Bebic Jovan, Lehn Peter, “Hybrid power flow controller and method.” Patent EP 1573878, class HO253 / 18, published September 17, 2005) [3].

The disadvantage of network IECs is the limited interval of guaranteed energy supply, determined by the stored energy of the NOE, as well as the high cost of the drive.

To eliminate the above disadvantages, a combined IEC scheme is proposed, which differs from the previous ones (stand-alone and network IEC) in the following features:

- contains at least three sources of electricity in the form of an SG generator, autonomous and network converters with drives;

- may include a wide range of additional sources of electricity, for example, wind turbines, photomultipliers, fuel cells, etc. These sources are connected to the load buses: asynchronous AG generator for wind turbines through an ac-dc-ac converter, other sources through ac-dc converters;

- converters can be performed both on the basis of power semiconductor devices (SPP), and on the basis of high-voltage vacuum devices (GDP).

The power and the number of SGs, AGs are determined by the base load power and / or excess power delivered to the network. The power of the NEE (AB, TE) is determined by the power of a single generator (SG or AG), which can fail. The energy stored in the NEE should provide uninterrupted power to the load for an interval of 1-10 minutes until the start of the backup generator. In addition, the NEE can equalize power fluctuations on the load buses due to the flicker of the wind turbines, changes in the illumination of the PMT, power swings between the load and the network in transient conditions, etc.

The use of pulse-width modulated (PWM) converters at increased frequencies (1-2 kHz) allows to reduce the installed filter power while ensuring the specified quality of the load voltage. The full controllability of the GDP and SPP devices allows to increase the speed of converters to a value of about 0.01 s.

To explain the essence of the invention, the figures (Figures 1-5) show diagrams and graphs illustrating the operation of the device.

The scheme of the proposed device in the minimum configuration is shown in figure 1, where the designations are:

1 - synchronous generator SG 6 kV; 2 - switchgear cabinets of switchgear 6 kW; 3 - load equivalent reduced to a voltage of 6 kV; 4, 4 ', respectively, converter cables 6/35 kV and 6 / 0.4 kV; 5.5 '- respectively 6 kV switchgear and 0.4 kV switchgear with filters; 6.6 '- respectively phase reactors of converters; 7.7 '- voltage converters (inverters) for GDP and SPP, respectively, PS-I1, PA-I2, respectively; 8.8 '- respectively RU-77 kV and RU-1 kV with voltage sources and storage (AB); 9, 9 ', respectively, the dc-ac converter and the EMF of the power system; 10 - block synchronization and common mode; 11, 12 - respectively, aggregate control systems of converters 7 and 7 '; 22 - block control system of the upper level.

As a prototype, a circuit can be used (JP Patent No. 2001 177 995 A, class H02J 3/28, G05F 1 / 66.67, published June 29, 2001) [4], which contains an AC voltage source (power system), a load, one or more in parallel connected converters with their control system, loaded onto an energy storage device, in parallel with which a photomultiplier photomultiplier is connected.

The disadvantage of the circuit [4] is the presence of a synchronous connection of the load and the power system, i.e. the absence of a network converter, especially on high-voltage vacuum devices, and as a result, insufficient reliability of the power supply to the load. For example, in the event of a power system accident at night, when the PMT does not work, and the capacity of the energy storage device does not provide continuous power, the load is interrupted.

The purpose of the invention is to ensure guaranteed quality and the absence of interruptions in the power supply of the load. The specified goal is achieved through the use of:

- different types of electric power sources: alternating current generators (SG and / or AG) and direct current (PMT), as well as different types of electric energy storage devices (AB and / or TE)

- heterogeneous voltage converters on power semiconductor devices (SPP) for stand-alone converters and high voltage vacuum devices (GDP) for a network converter.

- the use in the control system of a block of the upper control level, the inputs of which are connected to the outputs of the control system of each converter, and the outputs of which are connected to the inputs of the network and autonomous converters. In this case, the upper level unit sets the operating modes of the converters (charge-discharge), the settings of the capacities and voltages, as well as the procedure for their use in the implementation of switching operations, including the actions of protections in the event of an accident.

The simulation scheme of the proposed device in the Advanced Transient Program (ATP) is shown in the figure (figure 2). Designations are applied similar to the figure (figure 1). In addition to the power elements, in the lower part of the figure (figure 2) presents the elements of the automatic control system of the complex (SAUK). The following notation of variables is accepted:

US, IS (U _H , I _H ) - measured instantaneous values of voltages and currents;

PP, QQ (P _iso , Q _iso ) - measured values of active and reactive powers;

PUST, QUST - active and reactive power settings;

UPT, IPT (Ud, Id, I _АБ ) - measured instantaneous values of voltage and current of each converter on the DC side;

ALPH1, ALPH2 - control angles of converters 1 and 2;

AMPL1, AMPL2 - modulation coefficients of PWM converters 1, 2;

DALPH, DAMPL - signals of correction of angles and modulation coefficients, respectively;

RT, XT - total active and reactive resistances of transformers and reactors of each converter;

VR, VX, UINVR - active, reactive components and full voltage of inverters of converters. In addition, the IEC circuit monitors the voltages and currents of the reactors U _p , I _p , the voltages and currents of the valves, and other variables of interest.

SAUK contains software regulators of active and reactive power for each converter, as well as voltage regulators.

The experiments performed on the model showed that the optimal structure of the ACS is a structure containing, along with software regulators of active and reactive powers, load voltage regulators that provide the best quality of the transient process (the duration of the transient process is at the level of 0.05 s, there is no overshoot).

Figure 3 shows a block diagram of a control and regulation system of an autonomous I2 converter. In the indicated diagram, in the upper part, in the squares, sensors are indicated in the form of voltage and current transformers with measuring transducers (IP) of current, voltage, and power. The outputs of these IPs through signal cables are connected to the inputs of the PA control system unit (SUP.A), and the outputs of the unit with signals by the control angle α _o and modulation coefficient m _{o are} compared with the correction signals of the regulators P _A and Q _A. In addition, the signal for m is corrected by the output signal of the voltage regulator in the lower part of the figure (figure 3). The calculated signals are fed to the block of the phase-pulse device FIU PA, which generates control pulses of the valves PA.

The following values are used as measured values:

- at the load U _H , Q _H , P _H , which are compared with the settings (circled) U _Nust , Q _Hust , P _Nust ;

- on the converter PS Qia, Ria, which are compared with the corresponding values of the load power;

- at the output of the converter PA P _AB , U _AB , and the latter is compared with the _setting U _{AB back} .

The keys in the circuit Po and Qo with the indices P and 3 denote, respectively, the discharge and charge modes of the PA converter.

Regulators P, Q, U are adopted aperiodic, gain and time constants, which are selected depending on the parameters of the Converter and the load.

Aperiodic and notch filters are also installed in the chain of meters P, Q, U to eliminate the influence of harmonic distortion on the operation of the regulators. A similar structure is used for the network converter PS.

The figure (figure 4) shows a block diagram of a control and regulation system (ACS) of the combined converter, which corresponds to the circuit (figure 1). On the specified diagram in the upper part shows the power elements of the circuit of figure 1:

- DG diesel generator or asynchronous generator AG VEU (SHPP);

- converter network PS (I1), converter autonomous PA (I2).

An I3 converter may also be present if a PMT is used. The boxes and circles below show the measurement and filtering system. ACS of the combined IEC is represented by a dotted block diagram.

The SAUK includes a synchronization and common-mode device in the form of an autonomous generator that sets the amplitude, phase and frequency for the SAUK and the control panel of the diesel engine (SHUDG) The SAUK also contains block diagrams of the control system and the power unit, respectively, for PS and PA converters.

The graphs (figure 5) show the transients in the combined IEC (tgφ _n = 0.5) in the circuit (figure 1). In the initial state, the SG generator feeds the load; at the moment of 0.1 s the I1 network converter is turned on, at the moment of 0.3 s the SG is turned off, and at the moment of 0.6 s I1 is turned off and the autonomous I2 converter is turned on. The reverse transfer of load power from the I1 network converter is carried out at the moment of 0.9 s and is accompanied by a preliminary supply of pulses (at the moment of 1 s) to the I1 valves with the subsequent supply of power settings (1.2 s). The transition process is accompanied by a mutual interfering influence of the voltage regulators of both converters and the oscillatory process of voltage equalization on the equipment capacities. To eliminate mutual influence, the voltage regulator I2 must be switched off at the moment of switching on I1.

Active capacities (graph of Fig. 5a) are equal to: loads Рн = 1 MW, for I1 Pd = 1.15 MW, Riso ₁ = 1 MW, for I2-R _AB = 1.08 MW, Riso ₂ = 1.03 MW. Reactive power (figb) is equal to: load Qn = 0.5 MVA, for converters Qiso ₁ = Qiso ₂ = 0.5 MVA.

The analysis of the graphs (Fig. 5) shows that due to the presence of the NEE in the form of an AB (or TE) loaded on the I2 converter, the load supply interruption is completely eliminated with acceptable deviations of the voltage level.

The graphs (Fig. 5 c, d) respectively show the load voltage U _H = 3.58 / 3.48 kV and on the battery U U _AB = 880/867 V, as well as the load currents In = 110 A and Id = 15 A.

The graphs (Fig. 5 d, f) respectively show the voltage Ud = 77 kV and Up ₁ = 44/35 kV, and the currents Id = Ip ₁ = 85 / 48A for the moment of switching on the I1 converter equal to 1 s; on the graph (figure 5 g) - the change in currents Ip ₂ = I _AB = 7.24 / 2.6 kA.

The graph (Fig.5 h) shows the voltage changes on the load tires Uco ₁ = Uco ₂ = U _H = 4.9 kV. It is seen that voltage distortions on the load buses are practically absent.

The graphs (Fig. 5 and) show the load currents In = 170 A and currents Iso1 = 399/176 A. In the graph (Fig. 5 k), the current of the valve windings of transformers Ivod ₁ = 37 / 7A and Ivo ₁ = 53 / 5A.

The graph (Fig. 5 l) shows the currents of the switched-off I2 converter Ivod ₂ = 3.84 kA, decreasing to zero at the moment of 1.06 s and Ivo ₂ = 5.94 / 2.6 kA.

The graph (Fig. 5 m) shows the voltage of the valve windings Uwater ₁ = 20 kV and Uvo ₁ = 30 kV.

An analysis of the above graphs of instantaneous values of currents and voltages shows that they do not exceed the permissible values for IEC equipment.

From the graphs (figv, h), it follows that in the combined IEC, due to the presence of an energy storage device as part of I2, it is possible to completely exclude the interruption of power supply at the load both when the synchronous generator is turned off (time instant 0.3 s), and at the moment 0.9 s when transferring power from a stand-alone inverter I2 to a network inverter I1.

Sources of information taken into account when preparing an application for an invention.

[one]. V.M. Andreev, A.G. Zabrodsky, S.O.Kognovitsky “Integrated solar-wind power plant with energy storage based on the hydrogen cycle”, journal “Alternative Energy and Ecology of AEE” No. 2 (46), 2007 p. 99-105.

[2]. L. Gyugyi "Apparatus and method for interline power flow control". US patent 5698969, class G05F 1/70, published 1997

[3]. Bebic Jovan, Lehn Peter, Hybrid power flow controller and method. Patent EP 1573878, class HO253 / 18, published September 17, 2005

[four]. JP Patent No. 20011177995 A, Class H02J 3/28, G05F 1 / 66.67, published June 29, 2001.

Claims (1)

A combined multifunctional energy complex containing heterogeneous sources and an energy storage device connected to the inputs of a network and autonomous converters, the inputs of which are connected to a load, the outputs of the sensors of which are connected to the inputs of the aggregate automatic control systems of each converter, and the outputs of these systems are connected to the control circuits of each converter, characterized in that the network converter runs on high-voltage vacuum devices, and the outputs of agr converter control systems are connected to the input of the control unit of the upper level, the outputs of which are connected to the control circuits of the valves of each converter.