CN215186070U - PMU device suitable for distribution network parameter is measurationed - Google Patents

Abstract

The utility model discloses a PMU device suitable for distribution network parameter is measurationed, the device includes: the data acquisition unit is used for acquiring fundamental wave phasor values and power values of voltage and current of the power distribution network and power grid frequency and transmitting data to the data processing unit; the data processing unit is used for receiving and preprocessing data, estimating the value of the synchrophasor and carrying out error correction on the estimation result; and the communication unit adopts the matching of a wireless module and an optical fiber communication interface. The device meets the precision of synchronous phasor measurement under harmonic and simple harmonic interference, and has the characteristics of low cost, high reliability and easiness in networking.

Description

PMU device suitable for distribution network parameter is measurationed

Technical Field

The utility model relates to an electric power system field especially relates to a PMU device suitable for distribution network parameter is measurationed.

Background

From the development process of the synchronized phasor measurement technology, the clock synchronization technology based on the whole network GPS hardware and the data transmission technology based on the Ethernet are already applied to the synchronized phasor measurement of the power transmission network, and the clock synchronization technology based on the Ethernet IEEE1588 adopted in recent years for saving the cost is also developed and applied to a certain extent. However, the distribution network and the transmission network are very different in terms of network structure, structural stability, three-phase balance, load conditions, and the like. For example, in the aspect of network structure characteristics, although a distribution network has numerous nodes compared with a transmission network, each node of the distribution network has the characteristic of regional concentration, and is different from long-distance distribution among nodes in the transmission network; meanwhile, the network topology of the power distribution network has the characteristic of variability. This results in that neither the GPS hardware synchronization nor the ethernet synchronized phasor measurement technique is suitable for the application in the power distribution network. Secondly, the ethernet networking technology of the measurement system and the power supply of the device often have the problem that the implementation is not easy due to the installation environment.

SUMMERY OF THE UTILITY MODEL

In order to solve the application of synchronous phasor measurement technique in the distribution network, the utility model provides a PMU device suitable for distribution network is measurationed can satisfy the demand of distribution network to synchronous phasor measurement device. The device can realize synchronous time service of different measurement positions of the power distribution network by means of BD (Beidou)/GPS dual-system time reference and hardware clock oscillation source optimal configuration, and can meet the time-keeping precision of measurement requirements under the condition of losing a clock source for a period of time. Considering the problem that the Ethernet networking technology is limited by the installation environment and is difficult to realize, the device adopts a wireless networking mode, solves the communication problem in the use of a power distribution network, and simultaneously reserves an optical fiber communication interface, thereby improving the communication flexibility of the device. The device satisfies the precision of synchronous phasor measurement under harmonic and simple harmonic interference, has the characteristics of low cost, high reliability and easy networking, and is described in detail in the following:

a PMU device adapted for power distribution network parameter measurement, the device comprising:

the data acquisition unit is used for acquiring fundamental wave phasor values and power values of voltage and current of the power distribution network and power grid frequency and transmitting data to the data processing unit;

the data processing unit is used for receiving and preprocessing data, estimating the value of the synchrophasor and carrying out error correction on the estimation result;

the communication unit is matched with the optical fiber communication interface by adopting a wireless module;

wherein the content of the first and second substances,

the data acquisition unit includes: a current transformer, a voltage transformer, a program control amplifying circuit, a filtering module and an AD module,

the alternating current signal is sampled by the current transformer and then input into the program-controlled amplifying circuit, and the processed alternating current signal is transmitted to the AD module sampling end through the filtering module;

the alternating voltage signal is sampled by the voltage transformer and transmitted to the AD module sampling end after being processed by the filtering module.

Wherein the data acquisition unit further comprises: and the correction module is used for correcting the phases of front and rear signals of the current transformer and the voltage transformer.

The data processing unit receives synchronous time signals in a time layer and generates clock signals of the data acquisition unit and the communication unit;

and the data processing unit stores the measured data in the storage layer in real time.

In particular, the shell of the device is composed of an aluminum shell, and the size of the shell is 30cm multiplied by 12 cm.

The utility model provides a technical scheme's beneficial effect is:

1. the utility model discloses a FPGA + DSP structure can solve harmonic and simple harmonic interference under synchronous phasor parameter high accuracy estimation in the distribution network, greatly reduces parameter estimation's time delay.

2. The utility model discloses a wireless communication and fiber communication integrated configuration can solve nimble network deployment under complicated distribution network environment, and the synchronization of synchrophasor measuring device under the limited environment to the time, realize the high reliability transmission of synchrophasor parameter.

3. The experimental device is additionally provided with a correction circuit of the voltage/current transformer in the data acquisition unit, and the transformer error generated by long-time use is reduced.

Drawings

FIG. 1 is a block diagram of a PMU device suitable for power distribution network measurement;

in the attached drawings, a first is a data acquisition unit; ② a data processing unit; and thirdly, a communication unit.

FIG. 2 is a schematic diagram of a data acquisition unit;

fig. 3 is a schematic diagram of a communication unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, embodiments of the present invention are described in further detail below.

Example 1

As shown in fig. 1, the embodiment of the utility model provides a PMU device suitable for distribution network parameter is measurationed, include:

and the data acquisition unit is used for acquiring voltage and current signals. In order to meet the requirement that the fluctuation amplitude of a current signal of a power distribution network is large, a program-controlled amplifying circuit is introduced into a signal output test of a current transformer, and the signal intensity is improved. The device adds a filter circuit at a signal input end to reduce the influence of high-frequency secondary noise on a signal; in order to reduce the noise of the collected signals, the selected collection chip is provided with an anti-aliasing sampling configuration and is provided with a multi-channel synchronous sampling technology. The acquisition signal clock is generated by a unified time reference provided by a BD/GPS satellite, and the synchronization requirements of all data acquisition units are met. In order to improve the measurement accuracy, a transformer correction module is introduced at the transformer, so that the phase shift deviation generated by the transformer is reduced.

A data processing unit: the method is used for calculating the voltage and current signals, storing and encoding the synchronous measurement estimation result. The part bears the time synchronization task and meets the requirement that the whole measuring system runs at the same time. The optimal configuration of satellite time service and hardware time reference is achieved, and time service precision is improved. Consider the requirement of distribution network to synchronous measurement phasor rate and precision, the utility model discloses a FPGA combines with DSP, and FPGA is responsible for receiving, conveying and the code of data, and DSP mainly is used for realizing the calculation of synchronous measurement phasor, promotes data processing unit's processing speed and precision. The power distribution network has a complex operation environment, relatively large interference on synchronous measurement signals and relatively high requirements on data filtering processing. In order to meet the requirements of multiple measurement and low cost, a digital filter is adopted to preprocess signals.

A communication unit: for communicating the estimated synchrophasor parameters to the data concentrator in dependence on a preset communication frequency. Considering the complex environment of a power distribution network, particularly the limited communication environment; and has higher speed requirement on communication, and the communication unit adopts a wireless module and optical fiber communication for coordinated use. In a conditional power distribution network installation environment, an optical fiber communication mode is adopted, and the reliability of communication is improved. Adopt wireless network deployment mode, installation under the limited condition the utility model discloses a node distance requires to be less than 2km, realizes easily networking under the complex distribution network environment.

Example 2

The scheme of example 1 is further described below in conjunction with fig. 2-3, and is described in detail below:

and the data acquisition unit is mainly used for accurately acquiring fundamental wave phasor values and power values of voltage and current of the power distribution network and real-time power grid frequency and transmitting acquired signals to the data processing unit. The current signal acquisition and correction device mainly comprises a mutual inductor, a mutual inductor correction module, a current signal amplification module, a filtering module and an AD acquisition module. The transformer mainly converts voltage and current of a power distribution network into low-amplitude grade signals. In the environment of a power distribution network, the current variation range of a line is large, the device adopts wide-range variable current and multi-level gain amplification technology, and meanwhile, in order to meet application requirements, the device can provide multiple sampling rates. And a filter circuit is arranged at the front end of the acquisition, so that the influence of high-frequency noise is reduced.

The data processing unit is used for receiving the data of the data acquisition unit and preprocessing the data in a calculation layer so as to meet different application requirements of the power distribution network; the core of the method is to estimate the value of the synchrophasor according to the sampled data and carry out error correction on the estimation result. In a time layer, the device can receive a synchronous time signal, generate clock signals of the data acquisition unit and the communication unit, and meet the data coding requirements under the conditions of different-place clock synchronization and wireless networking. The time synchronization information is sent to the equipment needing time calibration by using a special serial port line, the advantage of serial port message time synchronization is exerted, the data of the whole system is compared, and the time synchronization information is automatically set in advance; in order to avoid the limitation that the accuracy of time correction is low, the message format is preset in advance and then the synchronization is carried out. Further, pulse signals are transmitted at intervals of strictly every second through a dedicated line, and the receiving apparatus performs timing using the received pulse edges. And recording the power distribution network event according to the estimation result in the storage layer, and storing the measured data in real time.

And the communication unit is used for ensuring that the device can perform hardware and software mutual communication under the conditions of remote clock synchronization and wireless networking, and meets the requirement of easy networking under the operating environment of the power distribution network by adopting a wireless networking mode in the region with limited operating conditions of the power distribution network. The requirement of high communication reliability under the operating environment of the power distribution network is met, the wireless module is matched with the optical fiber communication interface, and the high-reliability transmission of the messages with required frequency is adapted to the region with limited operating conditions of the power distribution network in a wireless receiving and optical fiber sending mode.

The embodiment of the utility model provides a except that doing special explanation to the model of each device, the restriction is not done to the model of other devices, as long as can accomplish the device of above-mentioned function all can.

Those skilled in the art will appreciate that the drawings are only schematic illustrations of preferred embodiments, and the embodiments of the present invention are given the same reference numerals and are not intended to represent the merits of the embodiments.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims (1)

1. A PMU device adapted for power distribution network parameter measurement, the PMU device comprising:

the data acquisition unit is used for acquiring fundamental wave phasor values and power values of voltage and current of the power distribution network and power grid frequency and transmitting data to the data processing unit;

the data processing unit is used for receiving and preprocessing data, estimating the value of the synchrophasor and carrying out error correction on the estimation result;

the communication unit is matched with the optical fiber communication interface by adopting a wireless module;

wherein the content of the first and second substances,

the data acquisition unit includes: a current transformer, a voltage transformer, a program control amplifying circuit, a filtering module and an AD module,

the alternating current signal is sampled by the current transformer and then input into the program-controlled amplifying circuit, and the processed alternating current signal is transmitted to the AD module sampling end through the filtering module;

the AC voltage signal is sampled by a voltage transformer and is transmitted to an AD module sampling end after being processed by a filtering module;

the data acquisition unit further comprises: the correction module is used for correcting the phases of front and rear signals of the current transformer and the voltage transformer;

the data processing unit receives synchronous time signals in a time layer and generates clock signals of the data acquisition unit and the communication unit;

the data processing unit stores the measured data in real time in the storage layer;

the shell of the PMU device consists of an aluminum shell body, and the size of the shell body is 30cm multiplied by 12 cm.

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